[7] 반도체 기초_10

감사합니다.

So now we're going to study about the semiconductor. The main focus on the semiconductor, we went to other things about the band structure, how to formulate, which is how we compose the structure band. That is the key factor in the the electronics. So now we are focusing some about the semiconductor electron transfer,

which means electron flow. So this is a mechanism for the semiconductor current flowing. So always the x-axis is something crystallized structure we identify by k. The y-axis is majorly like electron energy. This is the balance band and the conduction band. This is band gap. So actually the

initial status is fully filled down here. Fully occupied one of the items in the aligned object make the crystallized structure and one electron gets energy and then excites the conduction band. One electron If you're moving up one, then the electron conduction band leaves the hole in the balance band right here. So once moving up electron, which is an electron, then make the hole here, right?

But this hole is not stationary, which is moving like this way. This is the current flow. right so electron like a electron move this way something is it this way and then moving up whatever and then opposite direction of the current current is moving electrons moving this way current is moving this way right so all the thing is it gonna be this structure and this structure is a not stationary which is like moving.

Condition is what? Electric fuel. voltage = voltage divided by this term is electric fuel. So electric field only something moving. Not field only this is scatter. So we're moving back and forth whatever. Okay, the initial point, ending point is the same. It's going to be no electric field only. Okay, so metal consists of a metal atom that are linked in another with a metallic bond,

which is generally weaker than a covalent bond. You know what it is. So electrons can break free. participate the current conduction equivalent band gap associated with metal is zero. So this is we separated the insulator, semiconductor, metal case. Insulator too much band gap. So the electron trying to do moving but too much energy needed. So go back to the initial point because this is too much.

Electron cannot exist in here. Why? No state. It is in no state. No state means it cannot exist in electron. Conduction band and then balance band to a reasonable distance. There is a semiconductor sometimes on. on and off. So metal case is fully over there. No band gap. The half field here is very easily moving around. So this is a good conductor. So just gonna give you some one

specific topic. So never ever electron can't exist to this band gap. but sometimes stuck in here going up Well, not directly down something here stay and then down Temple can stay here. That is what? Some kind of defect Okay defect involved. Relector can stuck in here. Okay, it's no good, but sometimes there is a Most of the electronics may happen. Okay, so just there is something

besides the common concept just to let you know about this one. Okay, cannot exist in no state, but they did the stocking sometimes. Why? Because something defect on it. Not perfect crystallized structure. Okay, that case the conductive dimetrocontact always high. It's not sensitive to the change of the temperature. The insulator here involves the atomic bonding. They are much stronger than the semiconductor material, such as ionic bond.

The band here of the insulator is much greater than the semiconductor. This is much greater than the semiconductor here. It is difficult to electron to break loose from the atom's orbit. So very tightly bonding, so very much difficult to break loose energy or concentration of the free charge carrier is very low. So next.

The intrinsic semiconductor and silicon case. I told you before about the what is different things extrinsic and intrinsic. Extrinsic is something adopted semiconductor. You just modify intrinsic property. something by doping. Okay, so this is naturally for the silicon. Okay, silicon is a balanced band, conduction band, some energy band here, electrons are moving up.

Okay, so something electrons are moving up which means a free electron in here. Okay, hole is in here. Okay, how is it get the energy from here to here? Any kinds of energy, okay. The heat energy or photon energy, whatever. Okay, light or heat, any kinds of energy supply in here, break through this band structure. One or few electrons or much of an electron depends on the energy. into the conduction band which is a free carrier, free electron.

Which means this is bonding break into jumping, arm excited, which is the same thing. Covalent bonding here, electrons in here. This means something coping, arm means something, same as free energy. out of orbit here, with something with heat energy. Here is mentioned about the heat energy case, something to supply the energy here. Supply energy here from full electron may happen like this. Okay, so this case is perfectly bonded structure.

Right? A bonded structure. something free carrier like this. So free carriers in here 1 2 3 4 5 6 free carrier moving in this direction. The current is moving this direction. Why? Because electric field only. Voltage only means electric field on it. Right? This is the electron moving this way. Current is moving this way. Something like that.

Core is moving this way. Okay? That is the intrinsic semiconductor for silicon. Okay? The semiconductor material. So I mentioned semiconductor is fundamentally different from the conductor, different from the metal insulator, like a glass rubber material whose conductivity is between that of a perfect insulator and the perfect conductor between. So that's why semiconductor. Between insulator and conductor, that is semiconductor.

Silicon is group 4 means here. So naturally bonding structure similar, silicon, germanium, and carbon. So this is the same thing but the most popular is this one. In the periodic table, each silicon atom has four electrons in outer orbit. In consequence, each silicon atom that has a crystal structure lattice shared, there are four

cobalent bodies for the four neighbor atoms. We went through this one. The silicon atom resides in crystal lattice. Inner atomic spacing between the atom is determined by the balance of atomic attraction/repersion force. The density of a silicon atom is something blah blah blah. 2 cm this much atom is room temperature. 300k means room temperature.

Electrons are covalently bonded in orbit. The silicon atoms cannot be conducted. Column does not contribute to broad conductivity. Which is a tightly bonded orbit of a silicon atom that cannot contribute to conduct. Why? Because always free energy. Free electron can contribute to conduct. Only free electron.

Bonded electron is never ever contributed to the conducting. The conductivity of the semiconductor material is only rated concentration electron can be freely moving in a burr. Okay, this is what I mentioned here. The electrons wanted in silicon atom must be excited with it. Enough energy. Enough energy, right? Enough energy means something. Enough energy, not this much fall down. Okay, this is not enough.

Something moving up and then go back again but enough energy something moving up okay very much energy starting up and down there here lost bend destruction okay this much energy and getting down find the lost empty spot in here okay that is kind of barrier so enough energy there is a key point it's escape outer or available atom to the participant of current condensing. This is what? Free electron.

So intrinsic semiconductor that I mentioned here. Perfectly crystallized structure here is a two-dimensional presentation of a cobalancing single crystal lattice. Tightly bonding is what? This is no free electron. We just break it up here. One electron coming up, the hole in it here. So there is one free carrier, one free carrier, one

whole. So total two carriers. Which means you're breaking out which means something here to the here excited. So this concept is the same concept. So this is the same thing. How many electrons excited in balance band 2, cobalent, bonder. How many carriers? 1, 2, 3, 4, 5, 6, 7. 7 electrons. And how many holes? Intrinsic case is what exactly? 7 holes.

This number of holes, number of electrons should be matching up same. That is the intrinsic semiconductor. Keep in mind that there are discrete energy levels of both balance band and conduction band. Minimum energy of the conduction band is designated for something, blah blah blah. E C, conduction band here. And then maximum energy the government designates E balance band, blah blah blah. This is minimum energy from the conduction band here.

maximum energy is here. There is E, V here and EC, V denoted. So this is what I did. So intrinsic semiconductor in thermal generation, which is thermal energy supply, thermal energy The balance band electrons require some extra energy moving to the conduction band.

Okay, something, some electron is moving up like this. Okay, so this is the band structure energy band diagram. in generation. How we make generation. Then acceleration from conduction band fall back into the whole balance band. Both electrons in the hole disappear, losing energy, blah, blah, blah. So once excited, which is a generation, we call it out. Okay. So which is something once excited in here, something stuck and there may be here.

What? This electron is moving around. This conduction band is a collision may happen. Losing energy and then go down. Where? In here. This is the minimum energy of the conduction band. Okay Then Something may have a lose something this electron can be fall down to the original position in hole here Maybe in here there is equal to recombination So this is energy winning. This is energy lose. Okay, that's energy lose

energy need. Okay, thing is we control by carrier by energy. Okay, energy supply destruction. So which is here in covalent bond. This is the lattice here. The covalent bond electron which is one electron is moving out. Where? In here. It was two two letters here, but this is a breakdown of one electron out, one left over hole here. So this is one quasi-electron and then quasi-free one is a hole.

This is a semiconductor. So now doping the semiconductor as a donor acceptor. So first, we will look at the donor case first. The charger associated with something, arsenic, impurity atom, and silicon. Sarsonic is an atom donated to one electron to two, conduction band to two, produced in type silicon. group 5. Okay. So arsenic has five balanced electrons as silicon has only four electrons.

So one more electron. So more tendency to losing electron. The four electrons are arsenic from tetrahedron-covalent bond similar to the silicon. The fifth electron is available for The arsenic atom is called the donor because the ionized donate one electron to the conduction band, which is one electron to the EG2 donating one electron to the conduction band.

electron is minus here. So which is an excessive positive charge. Because one electron out, here is excessive electron is out. So ionized. This is ionized. So this is n-type selection. So, donor level in here. This is E, T. So donor level, how much this vendor width, whatever.

So we can figure out this number. So charge carrier in the semiconductor. So all the things we interest only the carrier. What is the carrier? Or plus or minus or electron. External electric field, which is voltage, electric field E or voltage divided by D. Applied material, electrons in conduction band are free to move in opposite direction of electric field.

Because there are many states available around the lamp. Okay, so whatever many states is available that's why electron can move. Okay, so electron moving this way, electric field this way, opposite direction. This direction, this direction. How about the horizon? Same direction in here and here. So, same direction moving. This is I go hopping, hopping. So was here, here, here. So here, here. So moving this direction.

Okay. So electric field. We cover whole thing like here. Okay. Electric field. Positive to negative. Okay. All the things negative. All the things positive. So I want to talk about the first what is intrinsic and extrinsic. Intrinsic means something I told you about.

Number of electrons, number of holes is the same. Okay, exactly the same. There is intrinsic semiconductor. I mentioned about one example, silicon carbon germany. Okay, so impure. Okay, impure. Okay, so pure, this is a pure semiconductor. Semiconductor. Which is a homogeneous material. homogeneous. Okay. So no impurity. Okay.

Homogeneous, pure semiconductor, whatever. We call it RAP. So next is extrinsic semiconductor. Extrinsic means no more impurity. No purity which is impure, which is the n-type or p-type number of carrier square. This is the definition. This is the intrinsic chemical definition. That is the extrinsic case. One is n-type is doping with quadra of donor. p-type is doping with quadra of donor. Accept. So doping means

Manipulating the carrier number. Manipulating carrier number. The manipulating control carrier number is all of the things about electronic working. I told you many times carrier number is very important. So electronic control is only carrier. Number control. Okay. What is conductivity? Told you many times. Okay. Number of n, q, mobility. Okay. Mu. Whatever. This is fixed. This is fixed.

Number of carrier control. That's it. Okay. Carrier control means conductivity in and out. No, no, no. On and off. So bearing conductivity. Novo semiconductor adding impurity. So n-type, p-type. n-type is the electron, p-type is the hole. We modify. Adding impurity means something not homogeneous but tedious. okay what is the n type and p type? n is electron so something about the

electron increase right the dopant which is more electron has okay tending to here I want to say here This column is what? Our electron is 4. 1, 2, 3, 4. So like a very much the neutral. So column 5 here, one more electron more. This is one less electron. Means tending to the P, this side tending to the N.

Okay. So N means here first, column 5 here, this column. This column is most likely N-type, wall-doping material here. So P, phosphorous here, arsenide, AES here, and standard a bit, you see here. antimony here. So these kinds of anti. How about the p-tie? One less electron means

one more hole. Okay, column three in here. This is p-tie. What it is? This is a boron and gallium, indium, or aluminum. Here is a p-type. Okay, blah, blah, blah. The banditryl semiconductor is 4. Most of our electron, the silicon is added many times here.

3s2n. 3s2, 3p2, 4 electrons. This is 4 electrons. What? This is n number 1. n is 2. This is n is 3. Okay. How about Joulemanium here? Joulemanium is 1, 2, 3, 4. Okay, which is, here is 4 electrons. Quantum number 4. Quantum principal number.

Okay, so most outer layer of electron number is the same. 4, 4, 4. But this is 2. Okay, this is 3 case. Charmaine's name is 4 case. Okay, how about the 3,5 condition? Because 3,5 means this one and then this one. Okay, aluminum here. This is it. How many electrons? 3 means less than 1.

because the natural is 4. 1 less is like a p type. Okay, so this is 5 right. Quantum number, this is the quantum number. N is 4. This is 4. Most outer layer electron is 5. 5 means here. So one more electron. This is the tending to the n type. This is the p type. That's why p type is here. Right? n type is arsenide here. Okay? Very simple.

n type, p type. Okay? This is one more and then one less. This is maybe two more and then two less. This is possible. But I am talking the most popular one is 3.5. That is the most popular doping material. Exyncy material. N-type or P-type. So something is mentioned before. Posporosaricinantimon. Or P-type Saricinantimon. Boron, Aluminium, and Germanium.

Okay, so positive charged donor atom left behind after ionization, immobile. The immobile means not moving. It does not contribute to the conduction, which means ionized Donor, whatever charge. Charge means here and type is plus charge. Donor, iron means Do or carrier. It's not carrier. Okay. So electron leaving, arom ionizing. Does count it in

electron concentration. So electron that positive is not carrier, but electron is a concentration carrier. Because activation is low, room temperature must be done, the room included in crystal will give electron to the conduction band. like a small thermal energy can make free electrons, even room temperature, which is n-type.

How about the p-type material is the same thing. The other way we think of the other way, negatively charged acceptor. means minus right after electron join the balance share is immobile immobile means no carrier and does not contribute to conduction okay this is not carrier so no conducting contribution to the conducting

The whole left behind the electron does the whole concentration is possible. That is a contributing conduction. So this is a carrier. This is not carrier. Okay. This is a carrier. This is not carrier. It's not carrier. Okay. Because activation is low, why the temperature, room temperature, The small-tonal energy that is enough to promote or excite the hole into the something in the electron from the balance band.

So, which is Nd is the tonal concentration. and A means the acceptor concentration. And this is the N type equilibrium. This is the P type equilibrium.

So intrinsic semiconductor, first we mentioned about the N-type P-type. So now structuralize how composed the P-type and N-type silicon. Okay, so electrical property. So intrinsic semiconductor. modified by doping. That is an extreme frame conductor. Doping means something put in purity. Purity atom.

So first, I want to say antipersse, antipersse, antimonie. Okay, adding something. So that is column 5. So once crystallized structure, all the things by silicon, silicon, silicon, silicon, and silicon. But this silicon moving out, take it out. then put in impurity atom, there is an antimon, put in here.

So what is column number five? So how many most outer electrons? How many antimon? One, two, three, four, not four, five. So which is a combine two of them here, two of them here. Two of them here, two of them here. One electron is not combined, which is three electrons. Okay, one left over. So that's why this electron is moving around. So this is what is better? So which is more carrier?

means more electron. So more electron means more better conductor. Better conductor. So extrinsic semiconductor is more better conductor properly then intrinsic semiconductor which is one more electron is a free electron okay. The other case is p-type. p-type is what?

Boron is added. This is impurity. So what's here? The silicon is here, silicon here, silicon here, silicon here. instead of silicon I just put into the boron okay what is the column number boron is three one two three column number okay how many electrons in most outer layer three so one of it make of two here

Two here, two here, three. So this is one vacant here. Vacant. Okay. Which means a hole. Hole means something on joint to the space. This is empty. It's the hole. So this is what? Like a free carrier. whole. Okay, so one more electron, one less electron. One less electron means one more whole.

Okay, so that's why p-type. n-type is here. one more electron case. So N-type P-type semiconductor can be applied to the various fields of the electron device. So this property, what? More electrons, more conductor than intrinsic. There is one more hole which is better than intrinsic semiconductor. So this is extrinsic extrinsic. So extrinsic is better conductivity than intrinsic semiconductor.

Ventructure is how to change it. This is things here. So silicon electron which is electron from starting to do here. right, this point. Okay. How about the doping is a phosphorus. First, the first phosphorus doping, where is located the starting point? Okay, here. Okay, so here thing is going to be, if you this thing going to be the carrier should be in conduction band.

Here to here is easier or here to here is easier. Here to here is much easier. Okay, which means that's why people adopt the material, phosphorus. Okay, so phosphorus, how close this one is? 0.045 electron power. Here is 1.1, so much closer here. So this is it. We need small energy to excite the one electron here to the here. Not from here to here. Okay. That's why people introduce some doping in an electronic material.

So here again, so let's just compare. Intrinsic case, n-type case, p-type case. Perfectly pure silicon material is covalent bonding, that is the intrinsic crystallizing, structuralizing intrinsic. So that case is the older thing is what? 1, 2, 3, 4, 1, 2, 3, 4, 8 electrons, the 4 of each. So there's one electron hole, there is a carrier, right?

That is intrinsic. OK. But some over here, something carried in this imputed doping. Imputed means, post-post, one electron's out. One is something. P-type is something. One hole is in here. Okay, so there is something intrinsic or extrinsic semiconductor. Okay, this is intrinsic semiconductor, this is extrinsic semiconductor. So I'm gonna explain here.

So extrinsic semiconductor, one is n-type, one is p-type. right. This is all silicon structure in here, one post-post atom here, one free electron, right, which is a covalent bonded electron, which is a silicon, all the things are silicon. So here is all the silicon, but only one thing is a bottom here. Okay, one is it. column, this is 5, this is column 2. So one more electron, one more electron, this is one last electron.

That's why the horizon is here. This is the horizon, this is the electrons in here. So these things how band structure can be can draw here and here and here. So N type here, this is a balanced band, a conduction band. This is a whole thing is silicon, right? So silicon is 1.12. 1.12 electron ball. So this thing is the dope point for the N type.

N type is in here. So which is something here, which is something jumping electron. Okay. So this is electron. Okay. So one electron is up. This is what thing is going to be neutral, but change to itself with a plus. This is a minus. Okay. This is maybe recombine is going to be neutral, which is a plus we called it up ionized donor state Ionized means change to plus

ionized donor state Okay So next one, band structure of a p-type, where is it going to be here p-type here here So P-type is major is carrier is hole. Right? This is electron. Right? Electron is residing, eugisily here. Whereas the hole is residing here. Hole is bottom. Okay?

So dope is going to be P-type is the bottom here. So here is this much distance moving. That's why less energy needed. Something hole created here. So this hole is created at the bottom here. It self-changed to minus. That is the ionizer acceptor state, which is ionization. This thing is two ionic changes. Okay, ionized state.

Okay, so this is anti-structure. Donor stage is withdrawing here. Very cross steady conduction band. Hall, acceptor. Very cross steady balance band here. This is clearly different thing is N type or P type. Where is going to be bent structure, donor, acceptor, in here. Now take a look at step by step.

anti first. Subtle silicon crystallized structure is doped in one part phosphorous here. This is a table group 4. Here is a phi. So all electron here. So things, the all balanced electron is bonded in cobalt and bond.

That's true. And this is the band structure for here. So energy, electron energy. one is a balanced electron and then conduction electron. This is one point, one two electron warfare, that is for silicon. So this phosphorus is doped into one part. So this is a major, but it should be some minor band structure should exist. So this is the top of the donor level, ED.

This is the donor. Donor. Here, new band line here, the state line here. So things here. So the band structure. So this is what? Something about the neutral No free carrier Okay This is it, no free carrier Okay So right side, look it up to the right side, phosphorus for this something

So temperature bigger than zero K means something thermal energy thermal energy applied to the structure. Then what? This is gonna be phosphorus ionized. One electron. For one phosphorus. Okay. Something is gonna be what? charge free electron. So here this thing in band structure here. This is some phosphorus

band structure here. So one plus means one electron up. One plus which means ionized. 1 electron. 1 plus 1 stock. 3 electron free carrier exist. Infectible donor state. Bigger than zero temperature. So this is N type. Next, take a look at the P type.

Same thing. Silicon structure here. All the things are bonding each other. One place, the boron is the top. Here is a group number three. Okay. Table. So here, the top is something boron atom. the same thing. This is a silicon band structure here. 1.12 electron volt for band gap. Then this is a

we call it an acceptor. Accept the band structure. This is a silicon band structure. Accept it one, orone is it Doped, substituted by the bottom atom. Then it's acceptor line here. Things are going to be fully filled, which means no free carrier. No free carrier. But once applied to temperature, zero is no temperature with low thermal energy.

but because then zero means something thermal energy supply to the structure. So ding is gonna be here one horse. One plus is how? So here, ionized plus. and then some Hosey here right was it here was it here neutral but one holes in here

One holes in here one holes in here. So three holes in here and then three ironized ironized to the minus So how many carrier here? 1, 2, 3. Horses in here. I'm gonna tell you later. This is not carrier. Make sure something is very carefully looking at. Things is gonna be ionized. One is not.

not carrier. This is not carrier. So I'm going to talk to you. So silicon, silicon with the silicon, it's a backbone, major material is silicon, right? So which is a discrete energy state is a single-purpose ion, which is here. Phosphorus in here. Do not say to do we call it ED. EC is conduction, EV is balance. E donor stays here.

So electron here. So energy band diagram for the semiconductor crystalline containing donor atom. Okay, donor atom here. So for the discrete atom, the electron must have something energy equal to the E vacuum or higher escape. Okay. More than this vacuum is going to be free electron. No atomic influence. No atomic influence here. So it is free energy. So inside is electrons in bonded atoms.

The influence of the nucleus. The semiconductor electron must have some energy, EC or greater, escape the influencer which is things going to be here. So electrons bound between, atoms in, balance bound. Okay. Now how many empty spots here?

1 and 2. Means 2. 4. How many electrons? Here we do 1, 2, 3. So two electrons here to do here and here to do here. Where from the one electron? Here donor state. Ionized one donor. One ionized donor.

That's why one, two, three. Total three. And down here something. So I'm going to tell you later. So now energy band diagram. First, now we delimited extrinsic semiconductor, extrinsic semiconductor, which is a modifier, which is a

n-type or p-type. So now, which is which this is n-type? This is p-type. So here take a look at this chart here. So n-type first. N-type. So conduction band here, balance band here. What is it going to be? N-type should be donor. This is the donor level. Alright, so this is the E-T.

This is what? Here, this is the E accept. So first, if we think as the silicon, so on also ionized donor, this is ionized 1, 2, 3, 4. Ionized donor means donor change to plus means electron is out, minus out.

Where? Here. 1, 2, 3, 4. Okay, so this is stay here. 2 is stay here, but 4 is up here. 1, 2, 3, 4. Right? So how many electrons? From here 1 2 3 4. Here 1 2 3 4. So carrier here 1 2 3 4.

Ionized donor will not count as the carrier. And here, look at the bottom here, the freeholds. Freeholds, how many? 1, 2, 3, 4, 5, 6, 7, 9, 10. So freehold means down here, P0. So this means plus. First was neutralized but then it changed to plus. Where is going to be electron? Something if you silicon up here. So 10 I'll put in whole. Here is a minus 1, 2,

So this is 10 electrons here, 10 holes in here, 10 electrons here. Here is a 14 up here, here is a 10 hole. So total carrier we set as something 24. Okay, 24 kL. Exactly the same here. This is P type here. So this is the unionized acceptor.

This remains the same. Here is the ionized plus. The ionized acceptor is the acceptor minus. So this is Minus 1, 2, 3, 4. Ionized oxidase not carrier. So where is this change to minus? Where is the plus in here? 1, 2, 3, 4. Carrier for whole. 4 over whole. Right? So look up here.

three electrons in here okay three electrons in here how many ten okay which is how many holes in here ten ten of the holes in here so four electrons four holes in here, four, ten holes in here, right? So total 14. How many carriers here? Ten of the electron.

Ten, fourteen, total 24, 24. Okay. 50 is a total carrier. Number of carriers is a something here 24 so as I told you again ionized acceptor this is remain stay as it is in here okay this is not carrier ionized donor and acceptor is not carrier anything in here and here band structure stay

Okay, that is a KU. So take a look here. Something donor, n-type, acceptor, p-type. So something is a E, balance band, E, conduction band, E, donor, E, D, right? As temperature going on, increased temperature means more thermal energy. Excited what? This one first. One here, two excited.

Then two carriers. Then what? High temperature means something. Everything is excited. Something. So 10 is over here. Acceptance. Again, temperature here, how many holes? One, two here. But more temperature is blah blah blah. Like tens of holes in here. Carrier number. So increase temperature a little bit, something, two, but more temperature, ten. So this is a hole, right? This is a hole.

This is the electron. Okay. So this is what it is. Everything changed. So donor and accept the ionization energy level. So what it is? linear something about ED energy level. Here on here is the E acceptor energy

level. So this is a silicon 1.12 but this is huge but this is little. Closal 2D conduction band, Closal 2D, Oxet, Balance band, and open material depends on the material level. Antimon, phosphorus, arsonic, number is different. Okay, little bit different. How about the boron is?

0.05 or aluminum is something 0.057 whatever. So very much close to this line is a donor. Very much closer to this line is a acceptor. So this is for definition. Extrinsic Semiconductor equation. So number of carriers, intrinsic carriers is number of electrons and

whole. Okay, we can figure out electron number, then we can figure out whole number. Whole number, I want to know. We do. I can give information electron number then give you the whole number. This is total carrier number. So anti-material with the only donor atoms. Donor atom same as the bubble bar. So we can put to this equation for the anti-material. How about the p times empty? So how about the acceptor?

Number, whole number of intrinsic number. Then we can figure out electron number with the whole number, total carrier number. G is the same as this one. Okay? With this one. So we can figure out. So, figure out something about the donor level and the acceptor level.

So now next carrier concentration and temperature. So how much is thermal energy into the system then how much carrier concentration canLAUGHTER which is a conductivity change. So first look it up.

This thing is silicon which is anti-phosphorus-doped silicon. Something like this structure. conduction band E, balance band, donor here. So first N is something number of majority carrier. This is N time. Time means majority is an electron.

then how much Nd means something donor of the electron Ni means something number of intrinsic conductivity electron which is from silicon this is a donor okay then this is a some majority carrier. So, take a look. So, this is

so depends on the temperature. What is going to be carrier number changed? Okay. So, First, zero Kelvin means no thermal energy. Means every possible carrier is not excited. Something stays on the steady state, which is N0. Means no carrier.

Okay, here is something. E, conduction band E, balance band E, donor. Okay, and more temperatures, a little bit higher temperature in here. How many? This one, this one, this one excited. electron, electron, electron. This is ionized.

Then here how many? One excited so this is four. Okay. So one is electron is up here. So three electron, whatever, three electron from here. right so one electron from here so total four electron right one is from silicon three is from donor total four electron then how many

one, four. So how many carriers total? five carriers total. 5 carriers total. How about this? More thermal energy. So how many carriers here? So this is the whole electron is up here. So this is how you know is 1, 2, 3, 4, 5, 6.

Right? Means here 6 electrons. Right? 6 electrons. Then how many? 1, 2, 3, 4, 5, 6. or then one electron from the silicon. So how many? Total seven electron and one hole. So total eight KD. Something like that. Okay. So next mole temperature means here one ionized two three four five six ionized so six electrons in conduction band

How many electron in here intrinsic this is intrinsic so three electron from intrinsic here means three holes here. Three holes in here. One, two, three holes and three electron excited. So three electron. Six is from the topping. Three is from the silicon. Nine electron total. So total 12 carrier.

Carrier is more and more, means more conductivity. So in here total number of donors, we know ND. ND+ means ionized donor. Right? So always ND number is bigger than ND+. Of course, right? This is the total doping. This is the sum of the doping.

Okay? Possibly equal. But naturally this is bigger than this one. So this is the whole concept of the carrier concentration depends on the temperature, which is the thermal energy. So more carrier means more better conductivity in semiconductor. But in conductor, depending on the temperature, there is another issue. Don't confuse about the temperature depending on conductivity.

We are talking about just the carrier, the number of carriers, not the other thing. So which is the thermal energy carrier increased in semiconductor. And this figure tells you about how these phenomena you can plot it out depends on the temperature number of carriers total carriers okay something carrier number is a from little temperature something increased

number of carrier increased something saturated and then one excited from silicon then increase right so higher temperature means something from bottom here is more energy this is the more energy than here okay so that's why more energy than here something exciting so which is intrinsic term range from here to here oh wow so silicon

So here is something some saturation region So this is the integer about the intrinsic or extrinsic carrier So this is, I guess what it is, the concentration depends on the temperature.

So carrier concentration is dropped to the semiconductor. This is the same as the previous figure, just different thing is the temperature. High to the low, 1 over inverse temperature. Here something, 1000 to the lower temperature. So this inversely parted. Here is something freezing out region here. And saturation range. And then intrinsic range, number of carriers, electron density.

cubic centimeter and how many electrons in there. And this is the lower-red-mid scale. Not linear scale, that's why something a little bit differentiated from the previous figure. So electron dacet is a function of the temperature. The solar current sample with The concentration is 10 to 15 cubic centimeters.

It is preferred to the objecdivacine saturation vision. Where the freak carrier density is. approximately equal to the top density. So this is something this is the measure. So n i is carrier number and n zero is much bigger. So n i is like a disregard something is

Minimal number. So this is the case. In the next page we are going to figure out more describe what it is. Electron density or whole density is measured by the function. of the temperature in the top to the semiconductor. Excellency, semicolon. And we can separate the three regions to freeze it out,

which is the temperature too small to ionize the top. And that is the free ionized. which is something KT, thermal energy much less than conduction minus donor level or donor minus the balance level, temperature is lower, lower is not enough, small to ionize the donor. there is a most electron ionized.

Okay, most of the electron donor are ionized. They are saturation region. And intrinsic which is a temperature so high so Ni number is much bigger than Doping Dastic. So it is not possible to operate the device in the intrinsic region, since the device always something high carrier density that I cannot control my electric field.

Which means every semiconductor has something upper temperature beyond the dirt which cannot be used in device. Then larger band gap is higher upper limit. So we depend on the band gap we can apply to different purpose. Okay. So this is the figure again, something can freeze it out within certain temperature and saturate it with the interquisite region.

Next, we're going to talk about the compensated semiconductor. This term is only introduced to first here. So I'm gonna explain what is definition. The definition contains both the donor and accept impurity. Out of the same region. So which means something diffusion, accept impurity to the entire or

which is accepted as a P-type into the N-type, like the N-type into the P-type, it's like mixed up. So these kinds of things are something interesting. But this is a happens all the time in fabrication process. Here, for example, I just introduced the FAT device, Field Effect Transistor.

This is the source, drain, the gate. This is how fabricate that I previously learn about it. Just like a backbone material, like a backbone material, the whole piece of thing is going to be first initiated. P-type silicon. Okay. So this was P-type silicon, but highly doped after doped to the P-type silicon and then this portion and this portion. All the portion is only spec-spec region adopted by n-type.

Like this is wasp-type but changed to n+ which is highly adopted n-type. Okay, so this region coexisting like wasp and then overrides by N time. So which is, this is looks like a major, this is a minor. So this is co-existing P time and N time. So look it up. So figure first. Here.

So this figure first, I will introduce this figure first. So here look it up. E, conduction band, E, balance band. Conduction band, the balance band. So here is E, donor, D. Here is E, nocceptor. This is a... ionized section. So this thing is 1, 2, 3, 4 is mechanically too heavy which is

fixed not moving. This is fixed not moving but this is ionized. This is - - - right? This is moving. This is moving particle carrier. This is not moving. This is not carrier. So this is not moving means no contribution to the conducting. This is no contribution. But this is the contribution. It is the same thing. Here is minus ionized.

here miss here plus here whole plus here this is the carrier but this is not carrier okay it's the moving this is the moving but is the contribution for conduction this is not contribution for conduction okay so this is the thing is gonna be something dono case and then accept the case. So look at first. So ionized donor is something ND+

how many? 4. Okay. Unionized donor which is how many? 1, 2. Right? So total donor, how many? So 2 plus 4 is total 6. This is 4 and then 2 is how many donor? 6. This is number of donor 6. This is 2. This is 4. 4 So same thing here. How many acceptor? The total acceptor here. How many ionized acceptor?

Any minus. Here is how many? Four. The unionized acceptor here. One, two. This is two. So total How many? 6. 6 total accept. Here is total 6 donor. So this is the thing. So here is something about it. About what is

going to be ionized case, unionized case, ionized case, unionized case. Okay, so we figure out this equation and this equation. Right, so look it up. Okay, so this is some of them is unionized, I mean they are ionized. unionized and ionized. If this case fully ionized how many? ND is gonna be 6. Then this is 0. ND is gonna be 0. So fully complete ionization is ND and PA.

Here this is ND and PA. Where is PA? This is PA is gonna be 0. Right? Something easy. Nd is going to be 0. Pa is going to be 0. In that case, first, looking at the first equation, we think about the total mutual radiation condition. How many? This is the minus. minus this is plus and plus it is neutralization first then what is the na

minus and Nd plus is the V equation from here. Now where is it which is the Nd plus put into this equation here. Na minus put into this equation here so V figure out this equation. When completely ionizes Nd is minus, Nd is minus, Pa is minus. So we got this equation. So the thing is mutual radiation that coming out from this in compensated semiconductor.

the realistic case. So we're gonna see more detailed indication here. So we're gonna go over what it is. The number of positive charge must be equal to the number of negative charge. So we got the first equation So electron and ionized acceptor that are negative charge, and the hole and ionized the hole donor and positive charge.

So uniformly the ducted semiconductor hit equilibrium, the free charge neutrality assuming Ionized. Assuming all ionized impurities. So we got this equation. Then we got previously this condition we got here. We talked about something first N0 case. N0 case. We printed this equation here. We got it here. And then we talked about the

N0 case. The second order equation. Then we solve based on the N0. Something we got this equation. Next one is how approach to P0 case. Same thing here. P0 we got this equation. The same thing. So N0 case and P0 case. So we think it's gonna be carrier number is donor minus acceptor. So donor minus acceptor is much higher than the intrinsic carrier.

Okay. So this case should be Na is greater than. This is no increased pressure with increasing temperature. It's not really efficient. Right. This is not really efficient. So this case is the most more efficient. So now we are talking the conductive of the semiconductor. First we are going to calculate the concentration of an electron. That we replaced by the P0. P0 equals something Ni square or N0.

then put in this equation. So that was the previous one we got here. So this equation to here and we just figured out based on the from here. Ni^2. So this is something based on the N0 alternate term is based on the P0.

Something you can figure out. This one. So like donors and accept assume to be fully ionized. There was a previously mentioned Na minus square Na, Nd plus is Nd. So the magnitude of the Nd minus Na is much greater than Ni. Something termed Ni^2 is much bigger.

So the concentration A and A is much greater than Ni. Then we can think about hens-reco. This one. Then accept concentration in our weight, the tonal of concentration. This one. In case it is greater than Ni, we can think about this. then this one. So which is a donor ionized carriers much greater than

except to ionize which is a hole. So there is a N0 is a dominant. Here is again except to ionize there is a whole as H, that is the electron oscillator to this way. This is the side P0. So that is it. All about it. So I'll just summarize all the things regarding to the neutrality and the carrier concentration. So here is something

Some of the books say something small d or capital A, but it is previously the same and small a. Okay, this is just small d and a. So it depends on the book they describe something capital or small letter. So this is the thing. So we talk about the electron and then hole. That is based on the previously we derived this equation.

This equation for hole. So carrier concentration. That depends on the net of concentration. Okay. All the thing is going to be way to compensate it. Say it is a semiconductor. This is a dopam-based wall, acceptor-based. We can say electron then hole.

Summarize all the terms, technical terms. We defined the concept each by each. So first it was open. Specs being purely down. There was a added to do. Say semiconductor which is the controlled amount of the expected purpose of the increasing. either electron or hole concentration. The intrinsic, there is an undopped, which is a purity of an atom, which is a pure semiconductor.

So we call that intrinsic semiconductor. The other is extrinsic semiconductor, that is a doped semiconductor. Semiconductor used properly controlled by, adding, imperial atoms. Some modification. And donor is an imperial atom which is increased electron concentration. Which is an N-type to open.

is something impure atoms which is increased to whole concentration which is a p-type dopam. So the end type is something that don't adopt the material. It can contain more electrons than whole. Majority is and ptile is now accepted the doped material which contains more holes than electrons.

This is the measure. The measure is the most abundant carrier given the semiconductor sample. Electron case is the n-tile. Hole case is ptile. Minority material there is something about. So, whole is in anti, electrons in the p-type material. So, whole, minority material. So, this is, I just leave the old technical term. Okay.

So, now I finished the semiconductor. conducted band structure. How we compose the band structure? Well located E conduction band, E balance band, E donor level, and E acceptor level. So we can count the carrier number. That's why carrier is most important property in conductivity.

We control conductivity by carrier, number of carriers. So number of carriers, well-located carriers, that is the sum we call it. state composed band. So next time we're going to talk about where carriers sit. The place we call it a state. So we are going to calculate the number of carriers electron.

something component this majority is something density function density function density of state function times forming function forming function is a probability function okay so next time I'm gonna more focus on the carrier Okay.