Help!! What is the max value of "on chip" capacito

[sbhalerao]

Hi to all,
I am currently working on a research problem.. I am stuck at a point where we need to decide whether our system can be fabricated on a chip...
Our system needs 1uF (16 nos.) capacitors, a 10 uF capacitor and a 5.5 uF capacitor .......
Can such values of capacitor be faricates using the standard chip making process in Si... My prof. seems to think that such high vales (anything about 100 nF) cannot be fabricated on the chip and will have to be included as an external discrete component... Could anyone give links to any papers that claim to have used such values of "on chip" capacitors??
Thanking all in advance,
Shantanu Bhalerao

 

[Mistico_Pereyra]

Re: Help!! What is the max value of "on chip" capa

Our system needs 1uF (16 nos.) capacitors, a 10 uF capacitor and a 5.5 uF capacitor .......

They are very high capacitors values, pf's values are high values!!

 

[Steven De Bock]

Re: Help!! What is the max value of "on chip" capa

uF capacitors seem big to me.

I already used a 0.35u process and several pF capacitors are in some circumstances feasible, allowable.

But uF capacitors? I think they should be external. Or maybe a redesign of your system can make the required capacitors smaller so you can make those integrated. It also depends on your process of course. But I have no idea about the capacitor sizes for other technologies

 

[wpchan05]

Re: Help!! What is the max value of "on chip" capa

Hi,

I checked out that for umc .25um mixed mode devices, the max geometric size is 100um. For a MIM cap having a size of 100um by 100um, you can only get ~ 10pF capacitance!

I have no access on other process kits, but I think a capacitance in microFarad range is not likely to be available in IC form.

 

[taofeng]

Re: Help!! What is the max value of "on chip" capa

several hundred pico Farad (pF) is still reasonable, more than that go for external component.

 

[samuel]

Re: Help!! What is the max value of "on chip" capa

too large to be made.