Professor Ronald L. Carter ronc@uta.edu http://www.uta.edu/ronc/ Semiconductor Device Modeling and Characterization EE5342, Lecture 25 -Sp 2002 Professor Ronald L. Carter ronc@uta.edu http://www.uta.edu/ronc/ L25 16Apr02

MOSFET Device Structre Fig. 4-1, M&A* L25 16Apr02

n-channel enh. circuit model G RG Cgd RDS Cgs S RD D RB Cbs Cbd Idrain Cgb DSS DSD RB B L25 16Apr02

SPICE mosfet Model Instance CARM*, Ch. 4, p. 290 L = Ch. L. [m] W = Ch. W. [m] AD = Drain A [m2] AS = Source A[m2] NRD, NRS = D and S diff in squares M = device multiplier L25 16Apr02

SPICE mosfet model levels Level 1 is the Schichman-Hodges model Level 2 is a geometry-based, analytical model Level 3 is a semi-empirical, short-channel model Level 4 is the BSIM1 model Level 5 is the BSIM2 model, etc. L25 16Apr02

SPICE Parameters Level 1 - 3 (Static) L25 16Apr02

SPICE Parameters Level 1 - 3 (Static) * 0 = aluminum gate, 1 = silicon gate opposite substrate type, 2 = silicon gate same as substrate. L25 16Apr02

SPICE Parameters Level 1 - 3 (Q & N) L25 16Apr02

Level 1 Static Const. For Device Equations Vfb = -TPG*EG/2 -Vt*ln(NSUB/ni) - q*NSS*TOX/eOx VTO = as given, or = Vfb + PHI + GAMMA*sqrt(PHI) KP = as given, or = UO*eOx/TOX CAPS are spice pars., technological constants are lower case L25 16Apr02

Level 1 Static Const. For Device Equations b = KP*[W/(L-2*LD)] = 2*K, K not spice GAMMA = as given, or = TOX*sqrt(2*eSi*q*NSUB)/eOx 2*phiP = PHI = as given, or = 2*Vt*ln(NSUB/ni) ISD = as given, or = JS*AD ISS = as given, or = JS*AS L25 16Apr02

Level 1 Static Device Equations vgs < VTH, ids = 0 VTH < vds + VTH < vgs, id = KP*[W/(L-2*LD)]*[vgs-VTH-vds/2] *vds*(1 + LAMBDA*vds) VTH < vgs < vds + VTH, id = KP*[W/(L-2*LD)]*(vgs - VTH)^2 *(1 + LAMBDA*vds) L25 16Apr02

SPICE Parameters Level 2 L25 16Apr02

SPICE Parameters Level 2 & 3 L25 16Apr02

Level 2 Static Device Equations Accounts for variation of channel potential for 0 < y < L For vds < vds,sat = vgs - Vfb - PHI + g2*[1-sqrt(1+2(vgs-Vfb-vbs)/g2] id,ohmic = [b/(1-LAMBDA*vds)] *[vgs - Vfb - PHI - vds/2]*vds -2g[vds+PHI-vbs)1.5-(PHI-vbs)1.5]/3 L25 16Apr02

Level 2 Static Device Eqs. (cont.) For vds > vds,sat id = id,sat/(1-LAMBDA*vds) where id,sat = id,ohmic(vds,sat) L25 16Apr02

Level 2 Static Device Eqs. (cont.) Mobility variation KP’ = KP*[(esi/eox)*UCRIT*TOX /(vgs-VTH-UTRA*vds)]UEXP This replaces KP in all other formulae. L25 16Apr02

SPICE Parameters Level 3 L25 16Apr02

Project 4 Part 1 Generate outputs duplicating any 8 of the following 14 figures in A&M* Figure 4-7a and b, Figure 4-8a and b, Figure 4-9a and b, Figure 4-10, Figure 4-11a only, Figure 4-12a only, Figure 4-13, Figure 4-15, Figure 4-19, Figure 4-20, Figure 4-23 L25 16Apr02

4-7a (A&M) L25 16Apr02

Figure 4-7b (A&M) L25 16Apr02

Figure 4-8a (A&M) L25 16Apr02

Figure 4-8b (A&M) L25 16Apr02

Project 4 Parts 2, 3, and 4 2. Generate outputs duplicating Fig 9.9 in M&K* 3. For each simula-tion, give the com-plete list of model parameters used. 4. Give a brief discussion of how Level 1, 2, and 3 are selected by Pspice depending on the parameter set used. L25 16Apr02

Body effect data Fig 9.9** L25 16Apr02

References CARM = Circuit Analysis Reference Manual, MicroSim Corporation, Irvine, CA, 1995. M&A = Semiconductor Device Modeling with SPICE, 2nd ed., by Paolo Antognetti and Giuseppe Massobrio, McGraw-Hill, New York, 1993. M&K = Device Electronics for Integrated Circuits, 2nd ed., by Richard S. Muller and Theodore I. Kamins, John Wiley and Sons, New York, 1986. L25 16Apr02