染料敏化太陽(yáng)能課件

1、課程講義 半導(dǎo)體概論南臺(tái)科技大學(xué)光電系 吳坤憲 1I. 半導(dǎo)體材料 (Materials)II. 半導(dǎo)體基本物理 (Physics)III. 半導(dǎo)體元件 (Devices)IV. 半導(dǎo)體製程 (Fabrication)V. 半導(dǎo)體 量測(cè) (Characterization)Introduction to Semiconductor Technologies2Chapter ISemiconductor Materials半導(dǎo)體材料35W for SemiconductorsWhat?導(dǎo)電性界於導(dǎo)體與絕緣體之間的材料Why? 半導(dǎo)體為現(xiàn)代電子工業(yè)的核心Where? 應(yīng)用於幾乎所有的電子產(chǎn)品(元件

2、)When? 1988年起電子工業(yè)成為世界上最大規(guī)模的工業(yè)How? 導(dǎo)電性可控制5What are Semiconductors?入門導(dǎo)電性界於導(dǎo)體與絕緣體之間的材料中階電阻係數(shù)約為10-4 108 -cm的材料進(jìn)階能隙約在 4eV以下之的材料6Solid-State MaterialsConductorMn: 105Cu: 8 106Fe: 107SemiconductorSi: 105 doped-Si: 105 10-5 InsulatorQuartz: 10-18Plastics: 10-13GaAs: 10-6Resitivity (-cm)Conductivity (-cm)-17

3、Portion of the Periodic Table related to semiconductors8Applications of Semiconductors Device10其他常用的半導(dǎo)體材料之相關(guān)名詞Bulk (本體)Substrate (基板)Film (薄膜)Epitaxial layer (磊晶層)12重要的半導(dǎo)體分類Element semiconductorCompound semiconductorIntrinsic semiconductorExtrinsic semiconductorDirect semiconductorIndirect semicondu

4、ctorDegenerate semiconductorNon-degenerate semiconductorCompensated semiconductorNon-compensated semiconductor14Crystallization of materials15Crystal and LatticeCrystal (結(jié)晶體)The semiconductor materials are basically assumed as single crystals to simplify the analysis.Lattice (晶格)The periodic arrengm

5、ent of atoms in a crystalLattice Constant (晶格常數(shù))The dimension a is called the lattice constantThree cubic-crystal unit cells. (a) Simple cubic. (b) Body-centered cubic (c) Face-centered cubic.16The Diamond Structure(a) Diamond lattice. (b) Zincblende lattice.17Crystal Plane and DirectionMiller indic

6、es of some important planes in a cubic crystalA (623)-crystal plane18Conduction Electron and HoleFormation of intrinsic carriers20Donor and AcceptorFormation of extrinsic carriers21Simplified Energy-Band Diagram23Energy-Momentum Band Diagram24Direct and Indirect Bandgap SemiconductorsDirect transiti

7、on: band to band photon emissionIndirect transition: via defect or impurity-related states phonon emissionDirect BandgapIndirect Bandgap26Effective Mass等效質(zhì)量是量子力學(xué)與古典力學(xué)之重要橋樑電子與電洞可以被視為古典物理中之帶電粒子。mn* (d2E/dp2)-1等效質(zhì)量等於能量-動(dòng)量曲線中曲率的倒數(shù)。曲率越小，等效質(zhì)量越大。拋物線的開口越大，等效質(zhì)量越大。電洞的等效質(zhì)量大於電子等效質(zhì)量mp* mn* For Si: mn* = 0.26 m0,

8、 mp* = 0.69 m0For GaAs: mn* = 0.063 m0, mp* = 0.57 m027Fermi Level費(fèi)米能階(EF)為被電子佔(zhàn)有機(jī)率為1/2的能量。費(fèi)米分布函數(shù)對(duì)稱於費(fèi)米能階。F(E) exp-(E-EF)/kT for (E-EF) 3kTF(E) 1- exp-(E-EF)/kT for (E-EF) 3kT在室溫下，能量高於(低於) 3KT之能階可視為空態(tài)(滿態(tài))28Carrier Concentration電子濃度為態(tài)位密度(density of state) N(E)與費(fèi)米分布函數(shù)(Fermi distribution) F(E)之摺積(convolu

9、tion)。n = Nc exp exp-(Ec-EF)/kT 電洞濃度為態(tài)位密度(density of state) N(E)與1-F(E)之摺積(convolution)。p = Nv exp exp-(EF-Ev)/kT費(fèi)米能階的位置決定了載子濃度。若 n = p = ni 時(shí)，EFi = (Ec + Ev)/2 + kT/2 ln(Nv / Nc) (Ec + Ev)/2 at 300 K 。稱為本質(zhì)濃度 (intrinsic concentration) ni2 = Nc Nv exp (-Eg/KT)ni 1010 cm-3 for Si and 106 cm-3 for GaAs

10、本質(zhì)濃度為半導(dǎo)體材料之重要參數(shù)。30Intrinsic, N-type and P-type semiconductors(1) Intrinsic(2) N-type(3) P-type31Fermi Level in Energy-band diagram32Various Impurities33Intrinsic and Extrinsic SiliconIntrinsic Semiconductor (本質(zhì)半導(dǎo)體)導(dǎo)電電子數(shù)量與電洞數(shù)量大約相同的半導(dǎo)體通常指未經(jīng)摻雜的半導(dǎo)體(Undoped Semiconductor)N-type Semiconductor (N型半導(dǎo)體)多數(shù)載子(

11、majority carrier)為電子的半導(dǎo)體矽晶體中摻雜V 族原子則形成N型半導(dǎo)體P-type Semiconductor (P型半導(dǎo)體)多數(shù)載子(majority carrier)為電洞的半導(dǎo)體矽晶體中摻雜III族原子則形成P型半導(dǎo)體34Impurities for III-V Compound SemiconductorsDonor (施體)Column VI (S, Se,Te, etc.) impurity substitute for column V (As)Acceptor(受體)Column II (Be, Zn, Cd, etc.) impurity substitute for column III (Ga)Amphoteric impurity (雙性雜質(zhì))Column IV (Si)substituting Ga for donor (low T)substituting As for acceptor (high T)35Carrier Concentration vs. Temperat