all resistors have voltage coeff..... it depends on the foundry process that u use.... for my case the salicided has higher vco.... u can do a quick check by checking the value for vco1 and vco2 in the model and compare the value...... higher value will have higher voltage coeff.....
if I not mistaken, the voltage charac depends on doping concentration......
I think voltage coefficient for both poly resistors should be neglectable for most of cases, specially comparing with any diffusion resistor or well resistor. So most foundry never model it.
1. High sheet resistance poly (1KOhm/sq) has a voltage coeff of about 0.8ppm/V
2. Normal poly resistors has no documented Voltage Coeff (would this mean that it is much smaller than High sheet resistance poly?)
Besides, the high-sheet resistance poly has a 2nd order temperature dependence while the normal has not ( I am not sure again if this is modeling issue )
Any idea on how high-sheet resistance is made? Is it just a salicide block mask?
The other way round: normal n-poly has more than 100-fold this VC, p-poly more than 300-fold, and both negative.
elbadry said:
Besides, the high-sheet resistance poly has a 2nd order temperature dependence while the normal has not ( I am not sure again if this is modeling issue )
a last question: in my process, the high-sheet resistance poly has TC1, TC2 and VC modeled and documented, the other poly resistor has only TC1 with no TC2 or VC. Can I safely conclude that the model is correct ( for the other poly resistor?)
I guess it will be correct to the first approximation. Normally, this should be enough. But in any case it is always better to use circuits which rely on resistor ratios than on their values.
I guess it will be correct to the first approximation. Normally, this should be enough. But in any case it is always better to use circuits which rely on resistor ratios than on their values.