19 BSIM2 Level-5 Model (bsim2)

The BSIM2 model is based on the industry standard efforts of the Compact Modeling Counsel (CMC) and the BSIM modeling group at the University of California, Berkeley. Click the following links for information about the BSIM2 model:

BSIM2 stands for Berkeley Short-Channel IGFET Model version-2. The BSIM2 is a semi empirical model suitable for devices with channel length from long channel to about 0.2 μm. Because it also models the output resistance, BSIM2 is suitable for both digital and analog applications. BSIM2 extracts all model parameters directly from physical devices. You can obtain an automated parameter extraction program, based on the IBM PC and HP4145 system, from the ILP office, Department of EECS, University of California, Berkeley. The following table shows the correspondence between the input parameter names and the equation symbols for the BSIM2 model.

Parameter	Symbol	Parameter	Symbol	Parameter	Symbol
`vfb`	V_FB,0	`lvfb`	V_FB,L	`wvfb`	V_FB,W
`phi`	φ₀	`lphi`	φ_L	`wphi`	φ_W
`k1`	K₁	`lk1`	K₁,L	`wk1`	K_1,W
`k2`	K₂	`lk2`	K_2,L	`wk2`	K_2,W
`eta0`	η_0,0	`leta0`	η_0,L	`weta0`	η_0,W
`mu0`	μ_0,0	`dl`	dl	`dw`	dw
`ua0`	U_a0,0	`lua0`	U_a0,L	`wua0`	U_a0,W
`uab`	U_aB,0	`luab`	U_aB,L	`wuab`	U_aB,W
`ub0`	U_b0,0	`lub0`	U_b0,L	`wub0`	U_b0,W
`ubb`	U_bB,0	`lubb`	U_bB,L	`wubb`	U_bB,W
`u10`	U_10,0	`lu10`	U_10,L	`wu10`	U_10,W
`u1b`	U_1B,0	`lu1b`	U_1B,L	`wu1b`	U_1B,W
`u1d`	U_1D,0	`lu1d`	U_1D,L	`wu1d`	U_1D,W
`mu0b`	μ₀B,₀	`lmu0b`	μ₀B,L	`mu0b`	μ₀B,W
`mus0`	μs_0,0	`lmus0`	μ_s0,L	`wmus0`	μs_0,W
`musb`	μsB,₀	`lmusb`	μ_sB,L	`wmusb`	μ_sB,W
`mu20`	μ_20,0	`lmu20`	μ_20,L	`wmu20`	μ_20,W
`mu2b`	μ₂B,₀	`lmu2b`	μ₂B,L	`wmu2b`	μ₂B,W
`mu2g`	μ₂G,₀	`lmu2g`	μ₂G,L	`wmu2g`	μ₂G,W
`mu30`	μ_30,0	`lmu30`	μ_30,L	`wmu30`	μ_30,W
`mu3b`	μ₃B,₀	`lmu3b`	μ₃B,L	`wmu3b`	μ₃B,W
`mu3g`	μ₃G,₀	`lmu3g`	μ₃G,L	`wmu3g`	μ₃G,W
`mu40`	μ_40,0	`lmu40`	μ_40,L	`wmu40`	μ_40,W
`mu4b`	μ₄B,₀	`lmu4b`	μ₄B,L	`wmu4b`	μ₄B,W
`mu4g`	μ₄G,₀	`lmu4g`	μ₄G,L	`wmu4g`	μ₄G,W
`etab`	ηB,₀	`letab`	η_B,L	`wetab`	ηB,W
`n0`	N_0,0	`ln0`	N_0,L	`wn0`	N_0,W
`nb`	N_B,0	`lnb`	N_B,L	`wnb`	N_B,W
`nd`	N_D,0	`lnd`	N_D,L	`wnd`	N_D,W
`vof0`	V_offset0,0	`lvof0`	V_offset0,L	`wvof0`	V_offset0,W
`vofb`	V_offsetB,0	`lvofb`	V_offsetB,L	`wvofb`	V_offsetB,W
`vofd`	V_offsetD,0	`lvofd`	V_offsetD,L	`wvofd`	V_offsetD,W
`ai0`	A_i0,0	`lai0`	A_i0,L	`wai0`	A_i0,W
`aib`	A_iB,0	`laib`	A_iB,L	`waib`	A_iB,W
`bi0`	B_i0,0	`lbi0`	B_i0,L	`wbi0`	B_i0,W
`bib`	B_iB,0	`lbib`	B_iB,L	`wbib`	B_iB,W
`vdd`	V_DD	`vgg`	V_GG	`vbb`	VBB
`vghigh`	V_G,high	`vglow`	V_G,low

Parameter Calculation

Except for mu0, dl, and dw, all device parameters are calculated from the following equation:

(19-1)

where P_i is any device parameter, P_i,0 is the parameter value for long channel length and width, and P_i,L and P_i,W are the channel length and width dependencies of the parameter, respectively. The following is an example showing how the flat-band voltage for a device with l = 2μm and w = 5μm is calculated from the model parameters.

(19-2)

Drain Current Model

Channel Width and Length

(19-3)

(19-4)

(19-5)

Threshold Voltage

(19-6)

where

(19-7)

Drain Saturation Voltage

(19-8)

where

(19-9)

(19-10)

(19-11)

(19-12)

(19-13)

(19-14)

(19-15)

Drain Current for the Subthreshold Region

These equations apply when V_GST ≤ V_glow.

(19-16)

where

(19-17)

(19-18)

Drain Current for the Triode Region

These equations apply when V_GST ≥ 0 and V_DS ≤ V_SAT.

(19-19)

where

(19-20)

(19-21)

(19-22)

(19-23)

(19-24)

(19-25)

(19-26)

(19-27)

(19-28)

Drain Current for the Saturation Region

These equations apply when V_GST ≥ V_ghigh and V_DS ≥ V_DSAT.

(19-29)

where

(19-30)

(19-31)

(19-32)

Drain Current for the Transition Region

These equations apply when V_glow ≤ V_GST ≤ V_ghigh .

Drain current equations are the same as those for the strong-inversion region, except that V'_GST replaces all V_GST terms. V'_GST is calculated from a cubic spline function to match the drain current and its first derivative at the upper and lower bounds (V_ghigh and V_glow).

(19-33)

All the coefficients, C_is, are automatically calculated during

(19-34)

(19-35)

(19-36)

Scaling Effects

For scaling effects, see Scaling Factors (scale and scalem).

Component Statements

This device is supported within altergroups.

Sample Instance Statement:

m2 (0 2 1 1) pchmod l=5u w=10u as=40u ad=40u pd=28u ps=28u m=1

Sample Model Statement:

model pchmod bsim2 type=p vfb0=-0.5 lvfb=0.5 wvfb=0.3 phi0=0.8 eta0=0.056 k1=0.5 eg=0.99 gap1=5.5e-04 trs=1e-3 trd=1e-3 xpart=0.5 rs=10 rd=10

Instance Syntax

Name  d  g  s  b ModelName parameter=value ...

Instance Parameters


`w`	`(m)`	Channel width.
`l`	`(m)`	Channel length.
`as`	`(m`²`)`	Area of source diffusion.
`ad`	`(m`²`)`	Area of drain diffusion.
`ps`	`(m)`	Perimeter of source diffusion.
`pd`	`(m)`	Perimeter of drain diffusion.
`nrd`	`(m/m)`	Number of squares of drain diffusion.
`nrs`	`(m/m)`	Number of squares of source diffusion.
`ld`	`(m)`	Drain diffusion length.
`ls`	`(m)`	Source diffusion length.
`m`	`1`	Multiplicity factor (number of MOSFETs in parallel).
`region`	`triode`	Estimated operating region. Spectre generates output number (0-4) in a rawfile.Possible values are off, triode, sat, subth and breakdown.
`trise`	`(C)`	Temperature rise from ambient.
`degradation`	`no`	Hot-electron degradation flag.Possible values are no and yes.
`isnoisy`	`yes`	Should device generate noise.Possible values are no and yes.

Model Syntax

model modelName bsim2 parameter=value ...

Model Parameters

Device type parameters


`type`	`n`	Transistor type.Possible values are n and p.

Threshold voltage parameters


`vfb0`	`-0.8 V`	Flat-band voltage.
`lvfb`	`0 V` μ`m`	Length dependence of `vfb`.
`wvfb`	`0 V` μ`m`	Width dependence of `vfb`.
`pvfb`	`0 V` μ`m`	Width-length dependence of `vfb`.
`phi0`	`0.75 V`	Surface potential.
`lphi`	`0 V` μ`m`	Length dependence of `phi`.
`wphi`	`0 V` μ`m`	Width dependence of `phi`.
`pphi`	`0 V` μ`m`	Width-length dependence of `phi`.
`k1`	`0.7` `V`	Body-effect coefficient.
`lk1`	`0` `V` μ`m`	Length dependence of `k1`.
`wk1`	`0` `V` μ`m`	Width dependence of `k1`.
`pk1`	`0` `V` μ`m`	Width-length dependence of `k1`.
`k2`	`0`	Charge-sharing parameter.
`lk2`	`0` μ`m`	Length dependence of `k2`.
`wk2`	`0` μ`m`	Width dependence of `k2`.
`pk2`	`0` μ`m`	Width-length dependence of `k2`.
`eta0`	`0`	Drain-induced barrier-lowering coefficient.
`leta0`	`0` μ`m`	Length dependence of `eta0`.
`weta0`	`0` μ`m`	Width dependence of `eta0`.
`peta0`	`0` μ`m`	Width-length dependence of `eta0`.
`etab`	`0 1/V`	Body-bias dependence of `eta0`.
`letab`	`0` μ`m/V`	Length dependence of etab.
`wetab`	`0` μ`m/V`	Width dependence of `etab`.
`petab`	`0` μ`m/V`	Width-length dependence of `etab`.

Mobility parameters


`mu0`	`400 cm`²`/V s`	Low-field mobility.
`lmu0`	`0 cm`²`/V s`	Length dependence of `mu0`.
`wmu0`	`0 cm`²`/V s`	Width dependence of `mu0`.
`pmu0`	`0 cm`²`/V s`	Width-length dependence of `mu0`.
`mu0b`	`0 cm`²`/V`² `s`	Body-bias dependence of `muz`.
`lmu0b`	`0 cm`² μ`m/V`² `s`	Length dependence of `x2mz`.
`wmu0b`	`0 cm`² μ`m/V`² `s`	Width dependence of `x2mz`.
`pmu0b`	`0 cm`² μ`m/V`² `s`	Width-length dependence of `x2mz`.
`mus0`	`450 cm`²`/V s`	Mobility in the saturation region.
`lmus0`	`0 cm`² μ`m/V s`	Length dependence of `mus0`.
`wmus0`	`0 cm`² μ`m/V s`	Width dependence of `mus0`.
`pmus0`	`0 cm`² μ`m/V s`	Width-length dependence of `mus0`.
`musb`	`0 cm`²`/V`² `s`	Body-bias dependence of `mus0`.
`lmusb`	`0 cm`² μ`m/V`² `s`	Length dependence of `mus0`.
`wmusb`	`0 cm`² μ`m/V`² `s`	Length dependence of `mus0`.
`pmusb`	`0 cm`² μ`m/V`² `s`	Length dependence of `mus0`.
`mu20`	`1`	Empirical channel length modulation parameter.
`lmu20`	`0` μ`m`	Length dependence of mu20.
`wmu20`	`0` μ`m`	Width dependence of `mu20`.
`pmu20`	`0` μ`m`	Width-length dependence of `mu20`.
`mu2b`	`0 1/V`	Body-bias dependence of `mu20`.
`lmu2b`	`0` μ`m/V`	Length dependence of `mu2b`.
`wmu2b`	`0` μ`m/V`	Width dependence of `mu2b`.
`pmu2b`	`0` μ`m/V`	Width-length dependence of `mu2b`.
`mu2g`	`0 1/V`	Gate-bias dependence of `mu20`.
`lmu2g`	`0` μ`m/V`	Length dependence of `mu2g`.
`wmu2g`	`0` μ`m/V`	Width dependence of `mu2g`.
`pmu2g`	`0` μ`m/V`	Width-length dependence of `mu2g`.
`mu30`	`5 cm`²`/V`² `s`	Empirical output resistance parameter.
`lmu30`	`0 cm`² μ`m/V`² `s`	Length dependence of `mu30`.
`wmu30`	`0 cm`² μ`m/V`² `s`	Width dependence of `mu30`.
`pmu30`	`0 cm`² μ`m/V`² `s`	Width-length dependence of `mu30`.
`mu3b`	`0 cm`²`/V`³ `s`	Body-bias dependence of `mu30`.
`lmu3b`	`0 cm`² μ`m/V`³ `s`	Length dependence of `mu3b`.
`wmu3b`	`0 cm`² μ`m/V`³ `s`	Width dependence of `mu3b`.
`pmu3b`	`0 cm`² μ`m/V`³ `s`	Width-length dependence of `mu3b`.
`mu3g`	`0 cm`²`/V`³ `s`	Gate-bias dependence of `mu30`.
`lmu3g`	`0 cm`² μ`m/V`³ `s`	Length dependence of `mu3g`.
`wmu3g`	`0 cm`² μ`m/V`³ `s`	Width dependence of `mu3g`.
`pmu3g`	`0 cm`² μ`m/V`³ `s`	Width-length dependence of `mu3g`.
`mu40`	`0 cm`²`/V`³ `s`	Empirical output resistance parameter.
`lmu40`	`0 cm`² μ`m/V`³ `s`	Length dependence of `mu40`.
`wmu40`	`0 cm`² μ`m/V`³ `s`	Width dependence of `mu40`.
`pmu40`	`0 cm`² μ`m/V`³ `s`	Width-length dependence of `mu40`.
`mu4b`	`0 cm`²`/V`³ `s`	Empirical output resistance parameter.
`lmu4b`	`0 cm`² μ`m/V`³ `s`	Length dependence of `mu4b`.
`wmu4b`	`0 cm`² μ`m/V`³ `s`	Width dependence of `mu4b`.
`pmu4b`	`0 cm`² μ`m/V`³ `s`	Width-length dependence of `mu4b`.
`mu4g`	`0 cm`²`/V`³ `s`	Gate-bias dependence of `mu4g`.
`lmu4g`	`0 cm`² μ`m/V`³ `s`	Length dependence of `mu4g`.
`wmu4g`	`0 cm`² μ`m/V`³ `s`	Width dependence of `mu4g`.
`pmu4g`	`0 cm`² μ`m/V`³ `s`	Width-length dependence of `mu4g`.

Mobility modulation parameters


`ua0`	`0 1/V`	Gate voltage dependence of mobility.
`lua0`	`0` μ`m/V`	Length dependence of `ua0`.
`wua0`	`0` μ`m/V`	Width dependence of `ua0`.
`pua0`	`0` μ`m/V`	Width-length dependence of `ua0`.
`uab`	`0 1/V`²	Body-bias dependence of `ua`.
`luab`	`0` μ`m/V`²	Length dependence of `uab`.
`wuab`	`0` μ`m/V`²	Width dependence of `uab`.
`puab`	`0` μ`m/V`²	Width-length dependence of `uab`.
`ub0`	`0 1/V`²	Second-order effect of gate voltage dependence of mobility.
`lub0`	`0` μ`m/V`²	Length dependence of `ub0`.
`wub0`	`0` μ`m/V`²	Width dependence of `ub0`.
`pub0`	`0` μ`m/V`²	Width-length dependence of `ub0`.
`ubb`	`0 1/V`³	Body-bias dependence of `ub`.
`lubb`	`0` μ`m/V`³	Length dependence of `ubb`.
`wubb`	`0` μ`m/V`³	Width dependence of `ubb`.
`pubb`	`0` μ`m/V`³	Width-length dependence of `ubb`.

Velocity saturation parameters


`u10`	`0 1/V`	Velocity saturation coefficient.
`lu10`	`0` μ`m/V`	Length dependence of `u1`.
`wu10`	`0` μ`m/V`	Width dependence of `u1`.
`pu10`	`0` μ`m/V`	Width-length dependence of `u1`.
`u1b`	`0 1/V`²	Body-bias dependence of `u1`.
`lu1b`	`0` μ`m/V`²	Length dependence of `u1b`.
`wu1b`	`0` μ`m/V`²	Width dependence of `u1b`.
`pu1b`	`0` μ`m/V`²	Width-length dependence of `u1b`.
`u1d`	`0 1/V`²	Drain-bias dependence of `u1`.
`lu1d`	`0` μ`m/V`²	Length dependence of `u1d`.
`wu1d`	`0` μ`m/V`²	Width dependence of `u1d`.
`pu1d`	`0` μ`m/V`²	Width-length dependence of `u1d`.

Subthreshold parameters


`n0`	`0`	Subthreshold swing parameter.
`ln0`	`0` μ`m`	Length dependence of subthreshold swing parameter.
`wn0`	`0` μ`m`	Width dependence of subthreshold swing parameter.
`pn0`	`0` μ`m`	Width-length dependence of subthreshold swing parameter.
`nb`	`0` `V`	Body-bias dependence of `n0`.
`lnb`	`0` `V` μ`m`	Length dependence of `nb`.
`wnb`	`0` `V` μ`m`	Width dependence of `nb`.
`pnb`	`0` `V` μ`m`	Width-length dependence of `nb`.
`nd`	`0 1/V`	Drain-bias dependence of `n0`.
`lnd`	`0` μ`m/V`	Length dependence of `nd`.
`wnd`	`0` μ`m/V`	Width dependence of `nd`.
`pnd`	`0` μ`m/V`	Width-length dependence of `nd`.
`vof0`	`1 V`	Threshold voltage offset in the subthreshold region.
`lvof0`	`0 V` μ`m`	Length dependence of `vof`.
`wvof0`	`0 V` μ`m`	Width dependence of `vof`.
`pvof0`	`0 V` μ`m`	Width-length dependence of `vof`.
`vofb`	`0`	Body-bias dependence of `vof0`.
`lvofb`	`0` μ`m`	Length dependence of `vofb`.
`wvofb`	`0` μ`m`	Width dependence of `vofb`.
`pvofb`	`0` μ`m`	Width-length dependence of `vofb`.
`vofd`	`0`	Drain-bias dependence of `vof0`.
`lvofd`	`0` μ`m`	Length dependence of `vofd`.
`wvofd`	`0` μ`m`	Width dependence of `vofd`.
`pvofd`	`0` μ`m`	Width-length dependence of `vofd`.
`subthmod`	`2`	Subthreshold model selector.

Impact ionization parameters


`ai0`	`0 1/V`	Hot-electron effect on `Rout` parameter.
`lai0`	`0` μ`m/V`	Length dependence of `ai0`.
`wai0`	`0` μ`m/V`	Width dependence of `ai0`.
`pai0`	`0` μ`m/V`	Width-length dependence of `ai0`.
`aib`	`0 1/V`²	Body-bias dependence of `ai0`.
`laib`	`0` μ`m/V`²	Length dependence of `aib`.
`waib`	`0` μ`m/V`²	Width dependence of `aib`.
`paib`	`0` μ`m/V`²	Width-length dependence of `aib`.
`bi0`	`0 V`	Hot-electron effect on `Rout` exponent.
`lbi0`	`0 V` μ`m`	Length dependence of `bi0`.
`wbi0`	`0 V` μ`m`	Width dependence of `bi0`.
`pbi0`	`0 V` μ`m`	Width-length dependence of `bi0`.
`bib`	`0`	Body-bias dependence of `bi0`.
`lbib`	`0` μ`m`	Length dependence of `bib`.
`wbib`	`0` μ`m`	Width dependence of `bib`.
`pbib`	`0` μ`m`	Width-length dependence of `bib`.

Transition region bound parameters


`vghigh`	`0.2 V`	Upper bound of the transition region.
`lvghigh`	`0 V` μ`m`	Length dependence of `Vghigh`.
`wvghigh`	`0 V` μ`m`	Width dependence of `Vghigh`.
`pvghigh`	`0 V` μ`m`	Width-length dependence of `Vghigh`.
`vglow`	`-0.15 V`	Lower bound of the transition region.
`lvglow`	`0 V` μ`m`	Length dependence of `Vglow`.
`wvglow`	`0 V` μ`m`	Width dependence of `Vglow`.
`pvglow`	`0 V` μ`m`	Width-length dependence of `Vglow`.

Length and width modulation parameters


`dl0`	`0` μ`m`	Lateral diffusion.
`dw0`	`0` μ`m`	Field oxide encroachment.
`lref`	`infinity m`	Reference channel length.
`wref`	`infinity m`	Reference channel width.
`xw`	`0 m`	Width variation due to masking and etching.
`xl`	`0 m`	Length variation due to masking and etching.

Temperature effects parameters


`temp`	`(C)`	Parameters measurement temperature. Default set by options.
`trise`	`0 C`	Temperature rise from ambient.
`compatible`	`spectre`	Encourage device equations to be compatible with a foreign simulator.This option does not affect the input synax.Possible values are spectre, spice2, spice3, cdsspice, hspice, spiceplus, eldo, sspice, mica, tispice and pspice.
`tempmod`	`432`	Temperature model selector.
`version`	`432`	Version selector.
`uto`	`0 C`	Mobility temperature offset.
`ute`	`-1.5`	Mobility temperature exponent.
`tlev`	`0`	DC temperature selector.
`tlevc`	`0`	AC temperature selector.
`ptc`	`0 V/C`	Surface potential temperature coefficient.
`eg`	`1.12452 V`	Energy band gap.
`gap1`	`7.02e-4 V/C`²	Band gap temperature coefficient.
`gap2`	`1108 K`	Band gap temperature offset.
`trs`	`0 1/C`	Temperature coefficient for source resistance.
`trd`	`0 1/C`	Temperature coefficient for drain resistance.
`xti`	`3`	Saturation current temperature exponent.

Overlap capacitance parameters


`cgso`	`0 F/m`	Gate-source overlap capacitance.
`cgdo`	`0 F/m`	Gate-drain overlap capacitance.
`cgbo`	`0 F/m`	Gate-bulk overlap capacitance.
`meto`	`0 m`	Metal overlap in fringing field.

Charge model selection parameters


`capmod`	`bsim`	Intrinsic charge model.Possible values are none, meyer, yang and bsim.
`xpart`	`1`	Drain/source channel charge partition in saturation for BSIM charge model, use 0.0 for 40/60, 0.5 for 50/50, or 1.0 for 0/100.
`xqc`	`0`	Drain/source channel charge partition in saturation for charge models, e.g. use 0.4 for 40/60, 0.5 for 50/50, or 0 for 0/100.

Parasitic resistance parameters


`rs`	`0` Ω	Source resistance.
`rd`	`0` Ω	Drain resistance.
`rsh`	`0` Ω`/sqr`	Source/drain diffusion sheet resistance.
`rsc`	`0` Ω	Source contact resistance.
`rdc`	`0` Ω	Drain contact resistance.
`rss`	`0` Ω `m`	Scalable source resistance.
`rdd`	`0` Ω `m`	Scalable drain resistance.
`minr`	`0.1` Ω	Minimum source/drain resistance.
`hdif`	`0 m`	Length of heavily doped diffusion.
`ldif`	`0 m`	Lateral diffusion beyond the gate.
`lgcs`	`0 m`	Gate-to-contact length of source side.
`lgcd`	`0 m`	Gate-to-contact length of drain side.
`sc`	`infinity m`	Spacing between contacts.

Junction diode parameters


`js`	`(A/m`²`)`	Bulk junction reverse saturation current density.
`is`	`1e-14 A`	Bulk junction reverse saturation current.
`n`	`1`	Junction emission coefficient.
`dskip`	`yes`	Use simple piece-wise linear model for diode currents below 0.1*`iabstol`.Possible values are no and yes.
`imelt`	`imaxA'	Explosion current, diode is linearized beyond this current to aid convergence.
`jmelt`	`jmaxA/m'²	Explosion current density, diode is linearized beyond this current to aid convergence.

Operating region warning control parameters


`alarm`	`none`	Forbidden operating region.Possible values are none, off, triode, sat, subth and rev.
`imax`	`1 A`	Maximum current, currents above this limit generate a warning.
`jmax`	`1e8 A/m`²	Maximum current density, currents above this limit generate a warning.
`bvj`	`infinity V`	Junction reverse breakdown voltage.
`vbox`	`1e9*tox V`	Oxide breakdown voltage.

Junction capacitance model parameters


`cbs`	`0 F`	Bulk-source zero-bias junction capacitance.
`cbd`	`0 F`	Bulk-drain zero-bias junction capacitance.
`cj`	`0 F/m`²	Zero-bias junction bottom capacitance density.
`mj`	`1/2`	Bulk junction bottom grading coefficient.
`pb`	`0.8 V`	Bulk junction potential.
`fc`	`0.5`	Forward-bias depletion capacitance threshold.
`cjsw`	`0 F/m`	Zero-bias junction sidewall capacitance density.
`mjsw`	`1/3`	Bulk junction sidewall grading coefficient.
`pbsw`	`0.8 V`	Side-wall junction potential.
`fcsw`	`0.5`	Side-wall forward-bias depletion capacitance threshold.

Process and power supply parameters


`tox`	`4e-8 m`	Gate oxide thickness.
`vdd`	`5 V`	Drain voltage at which parameters are extracted.
`vgg`	`5 V`	Gate voltage at which parameters are extracted.
`vbb`	`-5 V`	Body voltage at which parameters are extracted.

Default device parameters


`w`	`3e-6 m`	Channel width.
`l`	`3e-6 m`	Channel length.
`as`	`0 m`²	Area of source diffusion.
`ad`	`0 m`²	Area of drain diffusion.
`ps`	`0 m`	Perimeter of source diffusion.
`pd`	`0 m`	Perimeter of drain diffusion.
`nrd`	`0 m/m`	Number of squares of drain diffusion.
`nrs`	`0 m/m`	Number of squares of source diffusion.
`ldd`	`0 m`	Drain diffusion length.
`lds`	`0 m`	Source diffusion length.

Noise model parameters


`noisemod`	`1`	Noise model selector.
`kf`	`0`	Flicker (1/f) noise coefficient.
`af`	`1`	Flicker (1/f) noise exponent.
`ef`	`1`	Flicker (1/f) noise frequency exponent.
`wnoi`	`1e-5 m`	Channel width at which noise parameters were extracted.

Auto Model Selector parameters


`wmax`	`1.0 m`	Maximum channel width for which the model is valid.
`wmin`	`0.0 m`	Minimum channel width for which the model is valid.
`lmax`	`1.0 m`	Maximum channel length for which the model is valid.
`lmin`	`0.0 m`	Minimum channel length for which the model is valid.

Degradation parameters


`degramod`	`spectre`	Degradation model selector.Possible values are spectre and bert.
`degradation`	`no`	Hot-electron degradation flag.Possible values are no and yes.
`dvthc`	`1 V`	Degradation coefficient for threshold voltage.
`dvthe`	`1`	Degradation exponent for threshold voltage.
`duoc`	`1 S`	Degradation coefficient for transconductance.
`duoe`	`1`	Degradation exponent for transconductance.
`crivth`	`0.1 V`	Maximum allowable threshold voltage shift.
`criuo`	`10%`	Maximum allowable normalized mobility change.
`crigm`	`10%`	Maximum allowable normalized transconductance change.
`criids`	`10%`	Maximum allowable normalized drain current change.
`wnom`	`5e-6 m`	Nominal device width in degradation calculation.
`lnom`	`1e-6 m`	Nominal device length in degradation calculation.
`vbsn`	`0 V`	Substrate voltage in degradation calculation.
`vdsni`	`0.1 V`	Drain voltage in `Ids` degradation calculation.
`vgsni`	`5 V`	Gate voltage in `Ids` degradation calculation.
`vdsng`	`0.1 V`	Drain voltage in `Gm` degradation calculation.
`vgsng`	`5 V`	Gate voltage in `Gm` degradation calculation.

Spectre stress parameters


`esat`	`1.1e7 V/m`	Critical field in `Vdsat` calculation.
`esatg`	`2.5e6 1/m`	Gate voltage dependence of `esat`.
`vpg`	`-0.25`	Gate voltage modifier.
`vpb`	`-0.13`	Gate voltage modifier.
`subc1`	`2.24e-5`	Substrate current coefficient.
`subc2`	`-0.1e-5 1/V`	Substrate current coefficient.
`sube`	`6.4`	Substrate current exponent.
`strc`	`1`	Stress coefficient.
`stre`	`1`	Stress exponent.

BERT stress parameters


`h0`	`1`	Aging coefficient.
`hgd`	`0 1/V`	Bias dependence of `h0`.
`m0`	`1`	Aging exponent.
`mgd`	`0 1/V`	Bias dependence of `m0`.
`ecrit0`	`1.1e5 V/cm`	Critical electric field.
`lecrit0`	`0` μ`m V/cm`	Length dependence of `ecrit0`.
`wecrit0`	`0` μ`m V/cm`	Width dependence of `ecrit0`.
`ecritg`	`0 1/cm`	Gate voltage dependence of `ecrit0`.
`lecritg`	`0` μ`m/cm`	Length dependence of `ecritg`.
`wecritg`	`0` μ`m/cm`	Width dependence of `ecritg`.
`ecritb`	`0 1/cm`	Substrate voltage dependence of `ecrit0`.
`lecritb`	`0` μ`m/cm`	Length dependence of `ecritb`.
`wecritb`	`0` μ`m/cm`	Width dependence of `ecritb`.
`lc0`	`1`	Substrate current coefficient.
`llc0`	`0` μ`m`	Length dependence of `lc0`.
`wlc0`	`0` μ`m`	Width dependence of `lc0`.
`lc1`	`1`	Substrate current coefficient.
`llc1`	`0` μ`m`	Length dependence of `lc1`.
`wlc1`	`0` μ`m`	Width dependence of `lc1`.
`lc2`	`1`	Substrate current coefficient.
`llc2`	`0` μ`m`	Length dependence of `lc2`.
`wlc2`	`0` μ`m`	Width dependence of `lc2`.
`lc3`	`1`	Substrate current coefficient.
`llc3`	`0` μ`m`	Length dependence of `lc3`.
`wlc3`	`0` μ`m`	Width dependence of `lc3`.
`lc4`	`1`	Substrate current coefficient.
`llc4`	`0` μ`m`	Length dependence of `lc4`.
`wlc4`	`0` μ`m`	Width dependence of `lc4`.
`lc5`	`1`	Substrate current coefficient.
`llc5`	`0` μ`m`	Length dependence of `lc5`.
`wlc5`	`0` μ`m`	Width dependence of `lc5`.
`lc6`	`1`	Substrate current coefficient.
`llc6`	`0` μ`m`	Length dependence of `lc6`.
`wlc6`	`0` μ`m`	Width dependence of `lc6`.
`lc7`	`1`	Substrate current coefficient.
`llc7`	`0` μ`m`	Length dependence of `lc7`.
`wlc7`	`0` μ`m`	Width dependence of `lc7`.

Imax and Imelt:

The imax parameter aids convergence and prevents numerical overflow. The junction characteristics of the device are accurately modeled for current up to imax. If imax is exceeded during iterations, the linear model is substituted until the current drops below imax or until convergence is achieved. If convergence is achieved with the current exceeding imax, the results are inaccurate, and Spectre prints a warning.

A separate model parameter, imelt, is used as a limit warning for the junction current. This parameter can be set to the maximum current rating of the device. When any component of the junction current exceeds imelt, the base and collector currents are composed of many exponential terms, Spectre issues a warning and the results become inaccurate. The junction current is linearized above the value of imelt to prevent arithmetic exception, with the exponential term replaced by a linear equation at imelt.

Both of these parameters have current density counterparts, jmax and jmelt, that you can specify if you want the absolute current values to depend on the device area.

Auto Model Selection:

Many models need to be characterized for different geometries in order to obtain accurate results for model development. The model selector program automatically searches for a model with the length and width range specified in the instance statement and uses this model in the simulations.

For the auto model selector program to find a specific model, the models to be searched should be grouped together within braces. Such a group is called a model group. An opening brace is required at the end of the line defining each model group. Every model in the group is given a name followed by a colon and the list of parameters. Also, the four geometric parameters lmax, lmin, wmax, and wmin should be given. The selection criteria to choose a model is as follows:

  lmin <= inst_length < lmax  and   wmin <= inst_width  < wmax

Example:

model ModelName ModelType {

   1:     <model parameters> lmin=2 lmax=4 wmin=1 wmax=2

   2:     <model parameters> lmin=1 lmax=2 wmin=2 wmax=4

   3:     <model parameters> lmin=2 lmax=4 wmin=4 wmax=6

Then for a given instance

M1 1 2 3 4 ModelName w=3 l=1.5

the program would search all the models in the model group with the name ModelName and then pick the first model whose geometric range satisfies the selection criteria. In the preceding example, the auto model selector program would choose ModelName.2.

You must specify both length (l) and width (w) on the device instance line to enable automatic model selection.

Output Parameters


`tempeff`	`(C)`	Effective temperature for a single device.
`weff`	`(m)`	Effective channel width.
`leff`	`(m)`	Effective channel length.
`rseff`	`(`Ω`)`	Effective source resistance.
`rdeff`	`(`Ω`)`	Effective drain resistance.
`aseff`	`(m`²`)`	Effective area of source diffusion.
`adeff`	`(m`²`)`	Effective area of drain diffusion.
`pseff`	`(m)`	Effective perimeter of source diffusion.
`pdeff`	`(m)`	Effective perimeter of source diffusion.
`isseff`	`(A)`	Effective source-bulk junction reverse saturation current.
`isdeff`	`(A)`	Effective drain-bulk junction reverse saturation current.
`cbseff`	`(F)`	Effective zero-bias source-bulk junction capacitance.
`cbdeff`	`(F)`	Effective zero-bias drain-bulk junction capacitance.
`vto`	`(V)`	Effective zero-bias threshold voltage.
`vfb`	`(V)`	Effective flat-band voltage.
`phi`	`(V)`	Effective surface potential.
`k1`	`(``V )`	Effective body-effect coefficient.
`k2`		Effective charge-sharing parameter.
`eta`		Effective DIBL coefficient.

Spectre Circuit Simulator Components and Device Models ReferenceProduct Version 23.1, June 2023

19

BSIM2 Level-5 Model (bsim2)

Parameter Calculation

Drain Current Model

Channel Width and Length

Threshold Voltage

Drain Saturation Voltage

Drain Current for the Subthreshold Region

Drain Current for the Triode Region

Drain Current for the Saturation Region

Drain Current for the Transition Region

Scaling Effects

Component Statements

Sample Instance Statement:

Sample Model Statement:

Instance Syntax

Instance Parameters

Model Syntax

Model Parameters

Device type parameters

Threshold voltage parameters

Mobility parameters

Mobility modulation parameters

Velocity saturation parameters

Subthreshold parameters

Impact ionization parameters

Transition region bound parameters

Length and width modulation parameters

Temperature effects parameters

Overlap capacitance parameters

Charge model selection parameters

Parasitic resistance parameters

Junction diode parameters

Operating region warning control parameters

Junction capacitance model parameters

Process and power supply parameters

Default device parameters

Noise model parameters

Auto Model Selector parameters

Degradation parameters

Spectre stress parameters

BERT stress parameters

Output Parameters

Related Topics

Spectre Circuit Simulator Components and Device Models Reference
Product Version 23.1, June 2023