Ngspice BSIM (level 4) parameters -

Name	Parameter	Units	l/w
VFB	Flat-band voltage	V	*
PHI	Surface inversion potential	V	*
K1	Body effect coefficient	$\sqrt{V}$	*
K2	Drain/source depletion charge-sharing coefficient	-	*
ETA	Zero-bias drain-induced barrier-lowering coefficient	-	*
MUZ	Zero-bias mobility	$\frac{cm^{2}}{V \cdot sec}$
DL	Shortening of channel	μm
DW	Narrowing of channel	μm
U0	Zero-bias transverse-field mobility degradation coefficient	$\frac{1}{V}$	*
U1	Zero-bias velocity saturation coefficient	$\frac{\mu}{V}$	*
X2MZ	Sens. of mobility to substrate bias at v=0	$\frac{cm^{2}}{V^{2} \cdot sec}$	*
X2E	Sens. of drain-induced barrier lowering effect to substrate bias	$\frac{1}{V}$	*
X3E	Sens. of drain-induced barrier lowering effect to drain bias at V_ds = V_dd	$\frac{1}{V}$	*
X2U0	Sens. of transverse field mobility degradation effect to substrate bias	$\frac{1}{V^{2}}$	*
X2U1	Sens. of velocity saturation effect to substrate bias	$\frac{\mu m}{V^{2}}$	*
MUS	Mobility at zero substrate bias and at V_ds = V_dd	$\frac{cm^{2}}{V^{2}sec}$
X2MS	Sens. of mobility to substrate bias at V_ds = V_dd	$\frac{cm^{2}}{V^{2}sec}$	*
X3MS	Sens. of mobility to drain bias at V_ds = V_dd	$\frac{cm^{2}}{V^{2}sec}$	*
X3U1	Sens. of velocity saturation effect on drain bias at Vds=Vdd	$\frac{\mu m}{V^{2}}$	*
TOX	Gate oxide thickness	μm
TEMP	Temperature where parameters were measured	C
VDD	Measurement bias range	V
CGDO	Gate-drain overlap capacitance per meter channel width	$\frac{F}{m}$
CGSO	Gate-source overlap capacitance per meter channel width	$\frac{F}{m}$
CGBO	Gate-bulk overlap capacitance per meter channel length	$\frac{F}{m}$
XPART	Gate-oxide capacitance-charge model flag	-
N0	Zero-bias subthreshold slope coefficient	-	*
NB	Sens. of subthreshold slope to substrate bias	-	*
ND	Sens. of subthreshold slope to drain bias	-	*
RSH	Drain and source diffusion sheet resistance	$\frac{\Omega}{\square}$
JS	Source drain junction current density	$\frac{A}{m^{2}}$
PB	Built in potential of source drain junction	V
MJ	Grading coefficient of source drain junction	-
PBSW	Built in potential of source, drain junction sidewall	V
MJSW	Grading coefficient of source drain junction sidewall	-
CJ	Source drain junction capacitance per unit area	$\frac{F}{m^{2}}$
CJSW	source drain junction sidewall capacitance per unit length	$\frac{F}{m}$
WDF	Source drain junction default width	m
DELL	Source drain junction length reduction	m

xpart = 0 selects a 40/60 drain/source charge partition in saturation, while xpart=1 selects a 0/100 drain/source charge partition. nd, ng, and ns are the drain, gate, and source nodes, respectively. mname is the model name, area is the area factor, and off indicates an (optional) initial condition on the device for dc analysis. If the area factor is omitted, a value of 1.0 is assumed. The (optional) initial condition specification, using ic=vds,vgs is intended for use with the uic option on the .tran control line, when a transient analysis is desired starting from other than the quiescent operating point. See the .ic control line for a better way to set initial conditions.