Diffusion Resistor Model (rdiff)

The rdiff model is a diffusion resistor model, which accurately models the temperature, applied bias and back-bias dependencies of NWell, N+, and P+ resistors. It is described in the paper MODEL FOR DIFFUSION RESISTORS (NWell, N+, P+) USED IN CMOS IC DESIGNS by M.J.B.Bolt, FASELEC Process Development Group, PDG-93029, Modified 3rd May 1995.

Some extensions to that description are applied:

Appropriate model and instance parameter default values are used.

No clipping of parameters is performed. Parameter values are checked for validity. If invalid parameter values occur, the job is aborted with an error message.

For exact inverse behavior of the model in case of Vh less than Vl, the setting of Vbl=abs(Vb-Vl) is replaced by Vbl=min(abs(Vb-Vh),abs(Vb-Vl)). Additionally, the direction of Ih is inverted in this case.

Note: In noise analysis, rdiff instances will not generate any contribution, since there are no noise sources included in the rdiff model.

This device is supported within altergroups.

This device is dynamically loaded from the shared object /<install_dir>/tools.lnx86/cmi/lib/5.0/libphilips_sh.so

Sample Instance Statement

r2 (1 2 0) rdsn l=9u w=2u nb=0 m=1

Sample Model Statement

model rdsn rdiff level=1 tr=27 dta=0 rshr=2.5e3 wtol=0.22u rint=3.5u swvp=13.4u power=2 tcr1=1.5e-3 tcr2=1e-5 vpr=40

Instance Definition

Name  h  l  [b] ModelName parameter=value ...

Instance Parameters

1	`l=1.0 scale m`	Drawn length of resistor. Must be greater than zero. Scale set by option scale.
2	`w=1.0 scale m`	Drawn width of resistor. Must be greater than zero. Scale set by option scale.
3	`nb=0.0`	Number of bends in the resistor. Must be greater or equal zero.
4	`m=1.0`	Multiplicity factor. Must be greater than zero.

Model Definition

model modelName rdiff parameter=value ...

Model Parameters

1	`level=1.0`	`Level` of this model. Must be 1.
2	`tr (C)`	Reference temperature. Default set by option `tnom`.
3	`tref (C)`	Alias of `tr`. Default set by option `tnom`.
4	`tnom (C)`	Alias of `tr`. Default set by option `tnom`.
5	`dta=0 K`	Temperature offset of the device.
6	`trise=0 K`	Alias of dta.
7	`rshr=1.0e+3` Ω`/sqr`	Sheet resistance at reference temperature. Must be greater than zero.
8	`wtol=0.0 m`	Offset between the drawn and effective resistor width.
9	`tcr1=0.0 1/K`	Linear temperature coefficient of the resistor.
10	`tcr2=0.0 1/K`²	Quadratic temperature coefficient of the resistor.
11	`vpr=100.0 V`	Reference Pinch-off voltage.
12	`swvp=0.0 V/m`	Coefficient of the width dependence of `vp`.
13	`power=1.5`	Voltage exponent. Must be greater than zero.
14	`vdr=1.0 V`	Diffusion voltage at reference temperature.
15	`rint=0.0` Ω `m`	Interface resistance at reference temperature.
16	`tcrint1=0.0 1/K`	Linear temperature coefficient of the interface resistor.

Output Parameters

1	`vd (V)`	Diffusion voltage. Must be greater than zero.
2	`rsh (`Ω`/sqr)`	Sheet resistance. Must be greater than zero.
3	`vp (V)`	Pinch-off voltage. Must be greater than zero.
4	`r0 (`Ω`)`	Zero bias resistance. Must be greater than zero.

Operating-Point Parameters

1	`vhl (V)`	Absolute value of the applied bias across the resistor.
2	`vbl (V)`	Absolute value of the back-bias across the resistor.
3	`ih (A)`	DC current into the resistor.
4	`r (`Ω`)`	Actual resistance value.
5	`pwr (W)`	Power.

Parameter Index

In the following index, I refers to instance parameters, M refers to the model parameters section, O refers to the output parameters section, and OP refers to the operating point parameters section. The number indicates where to look in the appropriate section to find the description for that parameter. For example, a reference of M-35 means the 35th model parameter.


dta M-5	r OP-4	tcrint1 M-16	vhl OP-1
ih OP-3	r0 O-4	tnom M-4	vp O-3
l I-1	rint M-15	tr M-2	vpr M-11
level M-1	rsh O-2	tref M-3	w I-2
m I-4	rshr M-7	trise M-6	wtol M-8
nb I-3	swvp M-12	vbl OP-2
power M-13	tcr1 M-9	vd O-1
pwr OP-5	tcr2 M-10	vdr M-14

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