? adc中的采样电容一般是MIM电容还是MOS电容

douya

adc中的采样电容一般是MIM电容还是MOS电容？哪一种电容个更好？

Mos电容就是扩散电容吗？

libinphy

我不知道，但我们做的里面都是MOS电容，我做的是电源管理芯片

timesmile

MIM电容 双多晶电容也可以 主要看你的工艺 这样精度会高一些

phase2000

MM 电容

hongmy

pip,mim等，反正不会使用MOS电容作为采样电容，对电容要求比较高的一般都不使用MOS电容，电压系数，相对精度等太差

douya

楼上提到MOS电容匹配精度不高，根据ALLEN书上记载，MOS电容匹配精度0.05%，与pp电容一样。


我认为，采用mim电容，是由于mos电容的容值易受两端电压的变化。


还有一问：MOS电容是扩散电容吗

lioutau

一般是MIM 或PIP
MOS电容是非线性的哦

hijackly

MIM电容面积大，但是精确度高

andrew5473

一般是MIM, 但也有paper用MOS做，

waliley78751

It depends on the purposes.

For switch-cap delta-sigma ADC, usually a PIP-cap is used. MIM is also fine but costs a large die size.
MOS-cap is not suitable since its cap value highly depends on the terminal bias conditions.

However, if it is used for on-chip decoupling for surpressing EMI or power line noise, MOS-cap is a great candidate since its unit capacitance is the greatest.

Please be aware that there exist some tricks for layout of decoupling cap in general P-sub process.

If you guys are reviewing the variation characteristics of cap, I would say MOS cap "MIGHT" have the smallest variation since gate oxide is usually developed with dry oxidation process (very very slow...), which has better process control-ability. Inter-layer dielectric (ILD) such as P-P, P-M, or M-M are usually developed with CVD. In order to achieve lower thermal budget and less demand for thickness accuracy, these layers are usually not focused on precise control of thickness. (It does NOT mean CVD cannot be controlled accurately!!!) Well, this remark may differ from process to process. Just share some point of view.

[ 本帖最后由 waliley78751 于 2008-11-27 13:00 编辑 ]