min & max value for resistor & capacitor in integrated circuits

[vaziri.sale.eng]

what is the min & max resistor & capacitor value which we can make in integrated circuits ?
(for example in BiCmos Tech. or Another Tech.)

 

[palmeiras]

Hi vaziri.sale.eng,

You always can connect devices in parallel and series, and get the value of resistance/capacitance that you want. The limitation will be probably your requirement, silicon area. For example, some processes have high-resistance (without silicide) (sheet resistance --> somes kohms/square) that is possible to achieve 1 Mega ohns easily. However, if you dont have access to this resistance, it will not be possible.

 

[vaziri.sale.eng]

thank u dear

you mean that max resistor is 1 Mega ohm, ok , what about minimum resistor ?

i heard that the max capacitor which we may have in IC is about 1 Micro Farad , and we can not make higher than that
also i heard that the minimum capacitor in this way is 1 femto Farad and we can not make smaller than that

is this true?

 

[Colbhaidh]

The MIM capacitor is typically 2.1fF per square micron best case and 3.8fF per squre micron for a poly gate oxide capacitor.
Max resistance of GOhms is possible but max usable resistor has a sheet resistance of 2KOhms per square micron while a silicided resistor is around 2-4 Ohms per square.

 

[keith1200rs]

There aren't really any limits, within reason. However, for high value capacitors you will use a lot of area. For example 1uF could take up 500 square mm depending on the process. It is not a cost effective use of silicon, I would suggest. As Palmeiras said, you could easily make 1M ohm with a high resistance poly but that is by no means the maximum. You could make 10M, 100M - it is really just down to area.

At the lower end, again there are almost no limits, but there will be a minimum area with which to make a capacitor before you violate design rules. I have used 7fF capacitors in precision circuits and that was with a 0.8um process so I am sure 1fF would be no problem with smaller geometries. For resistance the problem is using a very low resistance. In both cases - low resistance and capacitance - the strays will be the limiting factor.

Keith.