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Diode Model

Type Name: d

The dc characteristics of the diode are determined by the parameters is and n. An ohmic resistance, rs, is included. Charge storage effects are modeled by a transit time, tt, and a nonlinear depletion layer capacitance which is determined by the parameters cjo, vj, and m. The temperature dependence of the saturation current is defined by the parameters eg, the energy, and xti, the saturation current temperature exponent. The nominal temperature at which these parameters were measured is tnom, which defaults to the value specified on the .options control line. Reverse breakdown is modeled by an exponential increase in the reverse diode current and is determined by the parameters bv and ibv (both of which are positive numbers).

The diode model is an enhanced version of the SPICE3 diode model, as used in NGspice, but with additional support for HSPICE model parameters.

The parameters marked with an asterisk in the area column scale with the area and/or the m (multiplicity) parameters given in the device line. The parameters marked with two asterisks scale with the pj (perimeter factor) parameter given in the device line.

Diode Model Parameters
name area parameter units default example
is, js * saturation current A 1.0e-14 1.0e-14
jsw ** sidewall saturation current A 0  
rs * ohmic resistance $ \Omega$ 0 10
trs, trs1   ohmic resistance 1st order temp coeff - 0  
trs2   ohmic resistance 2nd order temp coeff - 0  
n   emission coefficient - 1 1.0
tt   transit-time S 0 0.1ns
tt1   transit-time 1st order temp coeff - 0  
tt2   transit-time 2nd order temp coeff - 0  
cjo, cj0, cj * zero-bias junction capacitance F 0 2PF
vj, pb   junction potential V 1 0.6
m, mj   grading coefficient - 0.5 0.5
tm1   grading coefficient 1st temp coeff - 0  
tm2   grading coefficient 1nd temp coeff - 0  
cjp, cjsw ** sidewall junction capacitance F 0  
php   sidewall junction potential V 0  
mjsw   sidewall grading coefficient - 0.33  
ikf, ik * forward knee current A 1e-3  
ikr   reverse knee current A 1e-3  
eg   activation energy eV 1.11 1.11 Si,
0.69 Sbd,
0.67 Ge
xti   saturation-current temperature exponent - 3.0 3.0 junc,
2.0 Sbd
kf   flicker noise coefficient - 0 -
af   flicker noise exponent - 1 -
fc   forward-bias junction fit parameter - 0.5  
fcs   forward-bias sidewall junction fit parameter - 0.5  
bv   reverse breakdown voltage V infinite 40.0
ibv   current at breakdown voltage A 1.0e-3 2.0e-3
tnom, tref   parameter measurement temperature C 25 50
HSPICE Compatibility
level   device type selector      
tlev   equation set selector      
tlevc   equation set selector      
area   area default      
pj   sidewall perimeter factor default      
cta   junction capacitance temp. coeff.      
ctp   sidewall capacitance temp. coeff.      
tcv   breakdown voltage temp. coeff.      
tcv   junction potential temp. coeff.      
tcv   sidewall potential temp. coeff.      

The HSPICE compatibility parameters provide some minimal compatibility with the HSPICE diode model. The level parameter, if present, can take values of 1 and 3, corresponding to the HSPICE junction and geometric junction models. There is presently no support for the level=2 Fowler-Nordheim model. The tlev and tlevc parameters switch equation sets. Both take values of 0 and 1, and if set to any other value will assume a value of 1, i.e., higher values are not supported. The remaining parameters are as defined in the HSPICE documentation.

next up previous contents index
Next: Bipolar Junction Transistors (BJTs) Up: Semiconductor Devices Previous: Junction Diodes   Contents   Index
Stephen R. Whiteley 2022-09-18