SEMICONDUCTOR DEVICE PHYSICS AND DESIGN
3.9. CURRENT CONTINUITY 137 asET∼Eifor efficient recombination. Then the recombination rate becomes: U= σpσnvthNt σnnn [ nnpn−n^ ...
138 CHAPTER 3. CHARGE TRANSPORT IN MATERIALS If we consider a volume of space in which charge transport and recombination is tak ...
3.9. CURRENT CONTINUITY 139 Jn(x+ Jn(x) x x+ Δx) Δ Δ x R= recombination rate x Area A Loss Gain (a) (b) Particle current is cons ...
140 CHAPTER 3. CHARGE TRANSPORT IN MATERIALS δn(0) δn(x=L) δn(x) L x 0 Carrier injection Figure 3.27: Electrons are injected atx ...
3.9. CURRENT CONTINUITY 141 This gives for the excess carrier concentration δn(x)= δn(0) sinh ( L−x Ln ) +δn(L)sinh ( x Ln ) sin ...
142 CHAPTER 3. CHARGE TRANSPORT IN MATERIALS Thus the average distance an electron can move and then recombine is <x> = ∫∞ ...
3.10. PROBLEMS 143 Problem 3.7 The power output of a device depends upon the maximum voltage that the device can tolerate before ...
144 CHAPTER 3. CHARGE TRANSPORT IN MATERIALS Problem 3.13Electrons are injected into ap−typesilicon sample at 300 K. The electro ...
3.11. FURTHER READING 145 whereτis the carrier lifetime. Calculate the following: What fraction of the donors is ionized? What ...
Chapter 4 JUNCTIONS IN SEMICONDUCTORS: P-N DIODES 4.1 Introduction .................................... In the introduction to t ...
4.2. P-NJUNCTION IN EQUILIBRIUM 147 Let us start withp-andn-type semiconductors without forming a junction as shown in fig- ure ...
148 CHAPTER 4. JUNCTIONS IN SEMICONDUCTORS:P-NDIODES ⇓ + + eχ Evac EFn Junction formation (a) Electrons Fermi level is flat Wp W ...
4.2.P-NJUNCTION IN EQUILIBRIUM 149 Neutral p-region Neutral n-region negati v el y charged region posi ti v el y charged region ...
150 CHAPTER 4. JUNCTIONS IN SEMICONDUCTORS:P-NDIODES where the subscriptsnandprefer to then-side andp-side of the device. Using ...
4.2.P-NJUNCTION IN EQUILIBRIUM 151 p n –Wp 0 pp Structure Vp Potential profile Electron band profile pn np nn Wn Hole density El ...
152 CHAPTER 4. JUNCTIONS IN SEMICONDUCTORS:P-NDIODES The Poisson equation in the depletion approximation for various regions is ...
4.2.P-NJUNCTION IN EQUILIBRIUM 153 Please note that in the above equation, and throughout this chapter, thep−type semiconductor ...
154 CHAPTER 4. JUNCTIONS IN SEMICONDUCTORS:P-NDIODES 0 p-type n-type Structure Charge density –Wp Wn m Electric field Wn Charge ...
4.3. CURRENT FLOW: P-N DIODE UNDER BIAS 155 The built-in potential is given by eVbi = Eg− 0. 06 − 0 .206 eV =1. 1 − 0. 06 − 0. 2 ...
156 CHAPTER 4. JUNCTIONS IN SEMICONDUCTORS:P-NDIODES pn ppn n Vf EQUILIBRIUM FORWARD BIAS REVERSE BIAS (a) (b) (c) eVf Vr Vbi Vb ...
«
4
5
6
7
8
9
10
11
12
13
»
Free download pdf