SEMICONDUCTOR DEVICE PHYSICS AND DESIGN

2.3. ELECTRONS IN CRYSTALLINE SOLIDS 37 The wavefunction is spread in the entire sample and has equal probability (ψ∗ψ) at every ...

38 CHAPTER 2. ELECTRONIC LEVELS IN SEMICONDUCTORS Free states Bound st ates Isolated atoms E 1 E 2 E 3 E 4 Evac Free states Evac ...

2.3. ELECTRONS IN CRYSTALLINE SOLIDS 39 (a) (b) Figure 2.6: Brillouin zone of (a) the face centered cubic lattice and (b) the he ...

40 CHAPTER 2. ELECTRONIC LEVELS IN SEMICONDUCTORS general is dp dt =Fext+Fint However this is not very useful for a meaningful d ...

2.4. OCCUPATION OF STATES: DISTRIBUTION FUNCTION 41 + + + + + + + + + + + + Electron in a periodic potential Bloch theorem: ...

42 CHAPTER 2. ELECTRONIC LEVELS IN SEMICONDUCTORS spin. The spin of particles can take a value of 0 , 1 / 2 ,, 3 / 2 ,etc. Pa ...

2.5. METALS AND INSULATORS 43 Figure 2.8: Schematic of the Fermi function for electrons and other fermions. In general the posit ...

44 CHAPTER 2. ELECTRONIC LEVELS IN SEMICONDUCTORS Vacuum energy Conduction band Valence band Core level Core level Metal Semicon ...

2.5. METALS AND INSULATORS 45 + ke kh k Eleremovedctron aWssoaveveciated with ctor the missing electron Missing electron hole Fi ...

46 CHAPTER 2. ELECTRONIC LEVELS IN SEMICONDUCTORS ithasapositivecharge. It therefore responds to external electric and magnetic ...

2.6. BANDSTRUCTURE OF SOME IMPORTANT SEMICONDUCTORS 47 Valence band III II I I Heavy Hole Band II Light Hole Band III Split-Off ...

48 CHAPTER 2. ELECTRONIC LEVELS IN SEMICONDUCTORS 6 5 4 3 2 1 0 –1 –2 –3 –4 Eg (a) ENERGY (eV) (b) kz kx (100) (010) (001) (010) ...

2.6. BANDSTRUCTURE OF SOME IMPORTANT SEMICONDUCTORS 49 6 5 4 3 2 1 0 –1 –2 –3 –4 k ENERGY (eV) Eg GALLIUM ARSENIDE Direct bandga ...

50 CHAPTER 2. ELECTRONIC LEVELS IN SEMICONDUCTORS 6 5 4 3 2 1 0 –1 –2 –3 –4 0.3 L [111]Γ[100]X k (a) ENERGY (eV) GERMANIUM Indir ...

2.7. MOBILE CARRIERS 51 5 0 –5 k L M K L A ENERGY (eV) 5 0 –5 k L M K L A ENERGY (eV) 5 0 –5 k L M K L A ENERGY (eV) 10 k 1 M K ...

52 CHAPTER 2. ELECTRONIC LEVELS IN SEMICONDUCTORS Experimental bandgap EG(eV) Type of Temperature dependence Compound bandgap 0 ...

2.7. MOBILE CARRIERS 53 Evac EF Ec ENERGY Electrons in the conduction band can carry current Evac Ec E EV NERGY Conduction band ...

54 CHAPTER 2. ELECTRONIC LEVELS IN SEMICONDUCTORS ELEMENT VALENCE DENSITY CONDUCTION (gm/cm^3 ) ELECTRON DENSITY (10^22 cm–3) Al ...

2.7. MOBILE CARRIERS 55 EXAMPLE 2.1A particular metal has 1022 electrons per cubic centimeter. Calculate the Fermi energy and th ...

56 CHAPTER 2. ELECTRONIC LEVELS IN SEMICONDUCTORS Ec EV D ENSITY OF STATES Pure semiconductors n = p = ni = pi – ++ + (b) – – ...