《01第一章上_299203311》由会员分享，可在线阅读，更多相关《01第一章上_299203311（55页珍藏版）》请在金锄头文库上搜索。
1、Willy Sansen 10-05 011Comparison of MOST and Bipolar transistormodelsWilly SansenKULeuven, ESAT-MICASLeuven, Belgiumwilly.sansenesat.kuleuven.beWilly Sansen 10-05 012Table of contents Models of MOST transistors Models of Bipolar transistors Comparison of MOSTs and BipolarsRef.: W. Sansen : Analog De
2、sign Essentials, Springer 2006Willy Sansen 10-05 013From Bipolar to MOST transistors1994 2000CMOSCMOSBICMOSBIPGaAsBICMOSGaAs200 MHz100 GHz210 GHz1040 GHz12 GHz 12 GHz1040 GHzRef.ToshibaWilly Sansen 10-05 014The SIA roadmapYear Lmin Bits/chip Trans/chip Clock Wiringm Gb/chip millions/chip MHz1995 0.3
3、5 0.064 4 300 4 - 51998 0.25 0.256 7 450 52001 0.18 1 13 600 5 - 62004 0.13 4 25 800 62007 0.09 16 50 1000 6 - 72010 0.065 64 90 1100 7 - 8Semiconductor Industry Association2003Willy Sansen 10-05 015The law of Moore200520001995199019851980.1110YearL-MicronWilly Sansen 10-05 016ISSCC 2005 paper distr
4、ibution0510152025303540350 250 180 130 90 65nm LminDigital Analog/RFWilly Sansen 10-05 017Price MPW silicon for different L (nm)Cost MPW1001000100001001000nm$/sq.mmWilly Sansen 10-05 018MOST layoutpn+ n+BSGDLMWMn+ n+SG+D+p+p2009-4-11 清华大学微纳电子系 7NMOS和PMOS 管完整结构Willy Sansen 10-05 0111Polysilicon gateG
5、ate oxydeN-well CMOS technology三阱和双阱工艺示意图2009-4-11 清华大学微纳电子系 9MOS管的电路符号MOS管的工作原理水平电场垂直电场Willy Sansen 10-05 019MOST layout : Coxand CDSG+n+n+D+CD= n - 1CoxCoxCDptsiBCox=oxtoxCD=sitsitoxWilly Sansen 10-05 0110MOST layout : Coxand CDvaluesCD= n - 1 0.2Coxtsi=2si( -VBD)qNBExample : L = 0.35 m; W/L = 8to
6、x=50LminVBD= -3.3 V :Cox 5 10 -7F/cm2ox= 0.34 pF/cmsi= 1 pF/cm 0.6 Vq = 1.6 10-19CNB 4 1017cm-3tox= 7 nmCD 10 -7F/cm2tsi= 0.1 mCD=sitsiWilly Sansen 10-05 0112MOST IDSversus VGSand VDSIDSVGSVDSVT00IDSlinearsaturationVDS= ctSaturation because high VDSVGSVGSVGSVGSWilly Sansen 10-05 0113Table of content
7、s Models of MOST transistors MOST as a resistor MOST as an amplifier in strong inversion Transition weak inversion-strong inversion Transition strong inversion-velocity saturation Capacitances and fT Models of Bipolar transistors Comparison of MOSTs & Bipolar transistorsWilly Sansen 10-05 0114MOST I
8、DSversus VDSVDS0IDSlinearsaturationVGS-VTLinear resistorVDS VGS-VT1 (VGS-VT) = KPWLVGS-VTnRon=Willy Sansen 10-05 0115MOST parameters , KP , Cox, . = KPWLtoxoxCox=KP = Coxtox=50Lminp 250 cm2/VsLmin= 0.35 mtox= 7 nmCox 5 10 -7F/cm2KPn 300 A/V2ox= 0.34 pF/cmsi= 1 pF/cmn 600 cm2/VsWilly Sansen 10-05 011
9、6Example : Analog switch on CLWe want to switch 0.6 V to a load capacitance CLof 4 pF.We want to do this fast, with time constant 0.5 ns.Supply voltage VDD= 2.5 VVT= 0.5 VUse standard 0.35 m CMOS.Chooseminimum channel length and find an average VGS!vINVDDvOUTCLWilly Sansen 10-05 0117Example : Analog
10、 switch on RLWe want to switch 0.6 V to a load resistor RLof 5 k.W/L = 8 Supply voltage VDD= 2.5 V0.35 m CMOS: VT= 0.5 VvOUT? Ron? Chooseminimum channel length !vINVDDvOUTRLvINRonvOUTRLWilly Sansen 10-05 0118Body effect - Parasitic JFETn 1.2 1.5VT= VT0 + |2F| + VBS-|2F| n = 1+CoxCD|2F| + VBS 0.5 0.8
11、 V1/2|2F| 0.6 Vn = 1/ subthreshold gate coupling coeff. TsividisReverse vBSincreases |VT| and decreases |iDS | !Willy Sansen 10-05 0119Ex. : Analog switch with nonzero VBSSwitch 0.6 V to a load capacitance CLof 4 pFor a load resistor RLof 5 k.W/L = 8 (Ron= 125 VBS= 0)Supply voltage VDD= 2.5 V0.35 m
12、CMOS: VT= 0.5 VvOUT? for = 0.5 V-1Start with VBS= 0.vINVDDvOUTCLvINVDDvOUTRLWilly Sansen 10-05 0120Table of contents Models of MOST transistors MOST as a resistor MOST as an amplifier in strong inversion Transition weak inversion-strong inversion Transition strong inversion-velocity saturation Capac
13、itances and fT Models of Bipolar transistors Comparison of MOSTs & Bipolar transistorsWilly Sansen 10-05 0121wivssiMOST IDSversus VGSlogvsSlope q/nkTIDSIDSVGSVGSIDS=Kn (VGS-VT)2IDS (VGS-VT)IDS exp nkT/q VGSK=2 nKPn = ?WLKn 100 A/V2Kp 40 A/V22009-4-11 清华大学微纳电子系 31 二阶效应 背栅效应 作用 当 VBS0时，阈值电压变大，电流变小2、衬底
14、- 源极电压对电流的作用0(2| 2 |)TH TH F BS FVV V =+ 2009-4-11 清华大学微纳电子系 32转移特性曲线2009-4-11 清华大学微纳电子系 383、漏源电压对电流的作用 二阶效应 沟道长度调制效应 作用： 在饱和区，导电沟道产生夹断 VDS控制夹断区长度 夹断区长度的变化导致沟道电流变化2009-4-11 清华大学微纳电子系 39引入参数 沟道长度调制系数22111() ()22DnoxGSTH noxGSTHWLLICWVV CVVL LL+= DSLVL=21()(1)2D n ox GS TH DSWI CVV VL=+ L 随 VDS变化很小200
15、9-4-11 清华大学微纳电子系 40VDSID曲线Willy Sansen 10-05 0122MOST small-signal model : gm &rDSrDSgmvGSGDS=BGSDvGS+-Sgm= 2Kn(VGS-VT)= 2 KnIDS=WLVGS-VTWL2 IDSgm=dvGSdiDSiDSvGS+-Willy Sansen 10-05 0123The transconductance gmIs gm IDSor IDS ?Willy Sansen 10-05 0124MOST small-signal model : rDSVELIDS0IDSlinearsaturationVGS-VT=VDSsatIDS=Kn (VGS-VT) 2 (1 + VDS)WLrDS= ro= =1VELV
