SEMICONDUCTOR DEVICE PHYSICS AND DESIGN

8.7. DESIGN ISSUES IN HFETS 397 (a) (b) n+ GaAs cap AlGaAs GaAs 2DEG δ-layer A A' Rint Rint Rch Rch Rch Rn+ Rn+ EF(A) EF(A') AA' ...

398 CHAPTER 8. FIELD EFFECT TRANSISTORS (a) { { i-AlGaAs GaAs δ-doped Layer 2DEG n+-AlGaAs n+-GaAs { EF(cap) EF(GaAs) eφB (b) Fi ...

8.7. DESIGN ISSUES IN HFETS 399 (b) { { AlGaAs InGaAs δ-doped Layer 2DEG d -ds 0 Δd { p-InGaAs or GaAs dInGaAs EF 0 d -ds (c ...

400 CHAPTER 8. FIELD EFFECT TRANSISTORS GaAs AlGaAs n+ cap SOURCE GATE DRAIN (a) SOURCE DRAIN (b) GATE Figure 8.27: HFET structu ...

8.7. DESIGN ISSUES IN HFETS 401 (a) (b) GaN AlGaN SOURCE GATE DRAIN FP x y z y FP GATE GaN AlGaN SOURCE GATE DRAIN FP FP2 GaN Al ...

402 CHAPTER 8. FIELD EFFECT TRANSISTORS -1.60.0 2.0x10-6 4.0x10-6 6.0x10-6 8.0x10-6 1.0x10-5 -1.4 -1.2 -1.0 -0.8 -0.6 -0.4 -0.2 ...

8.7. DESIGN ISSUES IN HFETS 403 At the other extreme is the AlGaN/GaN system, whereEGin the channel is 3.4 eV. and the effective ...

404 CHAPTER 8. FIELD EFFECT TRANSISTORS Comparison of predicted fTand experimental work GaN InGaAS HEMT 0.00 0.05 0.10 0.15 0.20 ...

8.7. DESIGN ISSUES IN HFETS 405 18 20 22 24 26 28 10 15 20 25 30 35 050210FC-26A2 f = 40 GHz LG = 160 nm VDS = 30 V, VGS = -2.5 ...

406 CHAPTER 8. FIELD EFFECT TRANSISTORS (a) (b) 01234 0.0 0.5 1.0 1.5 2.0 2.5 With Field-plate Without Field-plate Channel Elect ...

8.7. DESIGN ISSUES IN HFETS 407 14 16 18 20 22 24 26 28 30 30 40 50 60 70 80 90 100 110 120 130 Lg=230 nm AlGaN/GaN HEMT Frequen ...

408 CHAPTER 8. FIELD EFFECT TRANSISTORS 50 100 150 200 250 300 0 10 20 30 40 50 60 RFR DS ( Ω ·mm) LG (nm) Std. HEMT InGaN back- ...

8.7. DESIGN ISSUES IN HFETS 409 Figure 8.36: a) Effect of the insertion of an ultra-thin layer of InGaN in the conduction band d ...

410 CHAPTER 8. FIELD EFFECT TRANSISTORS 40 45 50 55 60 65 70 75 80 80 90 100 110 120 130 VDS = 15 V InGaN back-barrier HEMT Stan ...

8.8. SMALL AND LARGE SIGNAL ISSUES 411 8.8 SMALLANDLARGESIGNALISSUESANDFIGURESOFMERIT ..... It is important to understand the be ...

412 CHAPTER 8. FIELD EFFECT TRANSISTORS Intrinsic model Gate CDG Drain RD CDS CGS CDC RG Rl gmVGS (a) Source Gate Drain Z Rs R 1 ...

8.8. SMALL AND LARGE SIGNAL ISSUES 413 whereCGis the gate-to-channel capacitance and describes the relationship between the gate ...

414 CHAPTER 8. FIELD EFFECT TRANSISTORS If the capacitance charging time is the limiting factor,atthecutofffrequencythegatecurre ...

8.8. SMALL AND LARGE SIGNAL ISSUES 415 is the frequency at which the power gain becomes unity, also called the power gain cut-of ...

416 CHAPTER 8. FIELD EFFECT TRANSISTORS 1 10 102 103 104 10 102 103 Diamond Ge GaAs Si InP SiC M AXIMUM ALLOWABLE VOLTAGE (V) MA ...