關於電阻的設計

squirrel316

在CMOS製程中
大致上可以知道說阻值等於sheet resistance*(L/W)
不過我有個問題就是L跟W值的選取
& Q+ b, Z4 i+ o, D2 ]& ]/ K$ }+ F假設我要讓L/W=2
$ t& k( w+ S  E. M$ z我可以有很多種選擇 像是2u/1u 4u/2u ...等
那請問一下這幾種選擇除了雜散電容造成的影響之外
2 {/ S8 T; P: _7 h還會有什麼影響
  S% p1 `+ g" H' D& t. X謝謝指教

seanyang1337

Dear squirrel316,
# G- {) ]& F/ o. j  W: CBasicly, the W should big enought and has a low bond(usually 2u for above 0.35um).
If you using too small scale like 1um, the accuracy will be very poor.
  p, U0 C8 c7 ^% ]8 [# F  TAnd it should be considered the eatch value.
As a reference, the foundry resistor test key, was measured by 10u/10u or larger.