SEMICONDUCTOR DEVICE PHYSICS AND DESIGN

2.7. MOBILE CARRIERS 57 electron density in the conduction band is n = ∫∞ Ec Ne(E)f(E)dE n = 1 2 π^2 ( 2 m∗e ^2 ) 3 / 2 ∫∞ Ec ( ...

58 CHAPTER 2. ELECTRONIC LEVELS IN SEMICONDUCTORS CONDUCTION BAND VALENCE BAND INTRINSIC CARRIER MATERIAL EFFECTIVE DENSITY (NC) ...

2.7. MOBILE CARRIERS 59 1017 1016 1015 1014 1013 1012 1011 1010 109 108 107 106 1000 500 200 100 27 0 –20 T ( ̊C) 0.5 1.0 1.5 2. ...

60 CHAPTER 2. ELECTRONIC LEVELS IN SEMICONDUCTORS The effective density of states becomes Nc =2 ( m∗doskBT 2 π^2 ) 3 / 2 =2 ( 1 ...

2.8. DOPING OF SEMICONDUCTORS 61 Silicon host atom Pentavalent donor impurity =+ = Silicon-like + Electron-ion All 4 outer elect ...

62 CHAPTER 2. ELECTRONIC LEVELS IN SEMICONDUCTORS Si As Positive ion E xcess el ectron + Ec Ed: Donor level E Ev Valence band C ...

2.8. DOPING OF SEMICONDUCTORS 63 and requires the solution of multiband effective mass theory. However, the acceptor level can b ...

64 CHAPTER 2. ELECTRONIC LEVELS IN SEMICONDUCTORS Si B Negative B ion Hole O ne el ectron tak en f rom the v al ence band to com ...

2.9. DOPING IN POLAR MATERIALS 65 Intrinsic range Si Nd= 10^15 cm–3 1000 300 200 100 75 50 500 1017 10 10 10 10 16 15 14 13 0 4 ...

66 CHAPTER 2. ELECTRONIC LEVELS IN SEMICONDUCTORS (b) (c) (^1001234567891011) (^1012) (^1013) 14 1015 1016 1017 1018 1019 1020 A ...

2.9. DOPING IN POLAR MATERIALS 67 C a Figure 2.24: The wurtzite crystal structure unit cell. In the ideal wurtzite structure the ...

68 CHAPTER 2. ELECTRONIC LEVELS IN SEMICONDUCTORS Ba++ Ti4+ Displacement of positive charges with respect to negative charges fe ...

2.9. DOPING IN POLAR MATERIALS 69 ZINC BLENDE Material e 14 (C/m^2 ) AlAs –0.23 GaAs –0.16 GaSb –0.13 GaP –0.10 InAs –0.05 InP – ...

70 CHAPTER 2. ELECTRONIC LEVELS IN SEMICONDUCTORS (a) (b) Surface Donors GaN 2DEG 0 200 400 600 800 1000 1200 -4 -3 -2 -1 0 1 2 ...

2.9. DOPING IN POLAR MATERIALS 71 (a) (b) (^0204060) 1x10^18 2x10^18 3x10^18 Charge (cm -3) Distance (nm) 30% (^020406080) 2x10^ ...

72 CHAPTER 2. ELECTRONIC LEVELS IN SEMICONDUCTORS Figure 2.29: Measured electrical characteristics as a function of temperature ...

2.10. TAILORING ELECTRONIC PROPERTIES 73 2.10 TAILORING ELECTRONIC PROPERTIES.................... In many applications we need b ...

74 CHAPTER 2. ELECTRONIC LEVELS IN SEMICONDUCTORS TYPE I HETEROSTRUCTURE A B TYPE II HETEROSTRUCTURE BROKEN GAP TYPE III HETEROS ...

2.10. TAILORING ELECTRONIC PROPERTIES 75 GeSi SiC SiOGaN 2 AlNInN GaAsInAs ZnOInP ZnOZnS GaPAlP AlAsAlSb GaSbInSb ZnSeCdS CdSeZn ...

76 CHAPTER 2. ELECTRONIC LEVELS IN SEMICONDUCTORS ∞ E 2 E 1 V(z) ∞ ∞ ∞ quantum well Valence band POSITIONz Conduction band quant ...