SEMICONDUCTOR DEVICE PHYSICS AND DESIGN

3.3. TRANSPORT AND SCATTERING 97 Collision Free flight Free flight Collision Collision Collision E Z = 0 Z Free flight CARRIER T ...

98 CHAPTER 3. CHARGE TRANSPORT IN MATERIALS How strongly V(r) couples the initial and final states How many final states there a ...

3.3. TRANSPORT AND SCATTERING 99 is called emission. Thus, both absorption or emission of energy can occur if the perturbation h ...

100 CHAPTER 3. CHARGE TRANSPORT IN MATERIALS Optical mode Acoustical mode k k 16 14 12 10 6 8 4 2 0 0.06 0.05 0.04 0.03 0.02 0.0 ...

3.3. TRANSPORT AND SCATTERING 101 Atomic displacement Bandedge positions EC r EV LATTICE VIBRATIONS BANDEDGE VIBRATIONS Figure 3 ...

102 CHAPTER 3. CHARGE TRANSPORT IN MATERIALS band;∞andsare the high frequency and static dielectric constants of the semicondu ...

3.3. TRANSPORT AND SCATTERING 103 8.0 7.0 6.0 5.0 4.0 3.0 2.0 1.0 0.0 0.00 0.10 0.20 0.30 0.40 0.50 0.60 0.70 0.80 0.90 1.00 Pol ...

104 CHAPTER 3. CHARGE TRANSPORT IN MATERIALS Alloy scattering Alloys are made from combinations of two or more materials. Since ...

3.4. TRANSPORT UNDER AN ELECTRIC FIELD 105 Low field response: mobility At low electric fields, the macroscopic transport proper ...

106 CHAPTER 3. CHARGE TRANSPORT IN MATERIALS Bandgap Mobility at 300 K (eV) (cm^2 /V-s) Semiconductor 300 K 0 K Elec. Holes C 5. ...

3.4. TRANSPORT UNDER AN ELECTRIC FIELD 107 One can understand this behavior physically by saying that at higher temperatures, th ...

108 CHAPTER 3. CHARGE TRANSPORT IN MATERIALS Example 3.3The mobility of electrons in pure GaAs at 300 K is 8500 cm^2 /V·s. Calcu ...

3.4. TRANSPORT UNDER AN ELECTRIC FIELD 109 You may assume the following values: μn(Si) = 1000 cm^2 /V·s μp(Si) = 350 cm^2 /V·s μ ...

110 CHAPTER 3. CHARGE TRANSPORT IN MATERIALS while ifNv>Ncwe get pmax=Nv This gives us for the maximum density: i) for Si, 2. ...

3.4. TRANSPORT UNDER AN ELECTRIC FIELD 111 electrons at such high electric fields is quite complex and requires either numerical ...

112 CHAPTER 3. CHARGE TRANSPORT IN MATERIALS 102 ELECTRIC FIELD (V/cm) CARRIER DRIFT VELOCITY (cm/s) 103 104 105 106 105 106 107 ...

3.4. TRANSPORT UNDER AN ELECTRIC FIELD 113 This gives a transit time of 0.123 ps. The transit time, if the saturation velocity ( ...

114 CHAPTER 3. CHARGE TRANSPORT IN MATERIALS Initial state has one electron Final state has two electrons + one hole Conduction ...

3.4. TRANSPORT UNDER AN ELECTRIC FIELD 115 M ate rial B a ndga reak do wn el ec tr i c (eV ) field (V/cm) G aA s 1.43 4 x 10^5 G ...

116 CHAPTER 3. CHARGE TRANSPORT IN MATERIALS Ec Ev –x 1 x 2 Ec Ev –x 1 0x 2 x (a) (b) Available empty states (holes) in valence ...