SEMICONDUCTOR DEVICE PHYSICS AND DESIGN

6.6. SECONDARY EFFECTS IN REAL DEVICES 277 JC < Jcrit JC = Jcrit JC = JKirk xpC wC xnC |E| Figure 6.18: Electric field profil ...

278 CHAPTER 6. BIPOLAR JUNCTION TRANSISTORS JC > JKirk(hypothetical) JC = JKirk wC (a) EC EF, n EV EF, p (b) eVBC |E| Figure ...

6.6. SECONDARY EFFECTS IN REAL DEVICES 279 JC > JKirk JC = JKirk wB (a) EC EF, n EV EF, p (c) eVBC ΔwB eNd,C -enp,C injected ...

280 CHAPTER 6. BIPOLAR JUNCTION TRANSISTORS MinimizingwC MaximizingNd,C Maximizingvs IncreasingNd,Cand decreasingwCboth lead t ...

6.6. SECONDARY EFFECTS IN REAL DEVICES 281 (b) (a) n - E p+ - B n- - C n+ Wbn ΔWbn VBC+ΔVBC VBC IC VA ideal characteristics Figu ...

282 CHAPTER 6. BIPOLAR JUNCTION TRANSISTORS where VA= ∫Wbn 0 p(x)dx p(Wbn)∂W∂VBCbn (6.6.18) is defined as the Early voltage. It ...

6.6. SECONDARY EFFECTS IN REAL DEVICES 283 COMMON BASE: During breakdown, emitter current is not affected COMMON EMITTER: At ver ...

284 CHAPTER 6. BIPOLAR JUNCTION TRANSISTORS In the common-base configuration, asVCBis increased, the breakdown is essentially si ...

6.6. SECONDARY EFFECTS IN REAL DEVICES 285 BASE EMITTER Emitter terminal Base terminal Cross-section p base n collector nnnnn To ...

286 CHAPTER 6. BIPOLAR JUNCTION TRANSISTORS The depletion width at the base-collector junction is shared between the base and th ...

6.6. SECONDARY EFFECTS IN REAL DEVICES 287 The slope of theJCvs.VCEcurve is then dJC dVCE ∼= ΔJC ΔVCE ∼=^80.^35 −^75.^8 4 Acm−^2 ...

288 CHAPTER 6. BIPOLAR JUNCTION TRANSISTORS This is the neutral base width. The actual base width will be larger and we need to ...

6.6. SECONDARY EFFECTS IN REAL DEVICES 289 To solve this problem we need to calculate the neutral base width in the device. Also ...

290 CHAPTER 6. BIPOLAR JUNCTION TRANSISTORS 6.7 PROBLEMS .................................... Temperature is 300Kunless otherwis ...

6.7. PROBLEMS 291 Calculate the collector current in the active mode with an applied emitter base bias of 0.5 V. What is the col ...

292 CHAPTER 6. BIPOLAR JUNCTION TRANSISTORS Problem 6.10The mobility of holes in silicon is 100 cm^2 /V·s. It is required that a ...

6.7. PROBLEMS 293 Section 6.5 Problem 6.16Consider annpnsilicon bipolar transistor in which Wb=2. 0 μm,Le=Lb=10. 0 μm, andDe=D ...

294 CHAPTER 6. BIPOLAR JUNCTION TRANSISTORS AlGaAs Eg= 1.7 eV ΔEc= 0.2 eV n-type: 10^17 cm-3 Graded region n-type: 10^17 cm-3 Ba ...

6.7. PROBLEMS 295 Problem 6.27Consider anpnSi-BJT at 300 K with the following parameters: Nde =10^18 cm−^3 Nab =10^17 cm−^3 Ndc ...

296 CHAPTER 6. BIPOLAR JUNCTION TRANSISTORS where the current and the excess charge are evaluated at the boundary. Using the exp ...