CMOS工艺下bandgap 负温度系数器件，为什么使用PNP管而不是用二极管？

scy8080

CMOS工艺下bandgap 负温度系数器件，为什么使用PNP管而不是用二极管？

hoodlum

小弟的看法是
會不會是標準CMOS的製程裡
; z7 i* S4 ~. v7 L2 M! ^無法做出二極體, 只能用寄生的
( ~8 F! r2 V. f- A! X- D0 Mvertical PNP呢???

leo911759

其實也是有的。

有一些Paper就是用Diode，或是NPN。

而會用PNP 是因為早期CMOS製程中，只能寄生等效PNP電路。
8 r' l  V0 Z/ A) M1 V0 a/ ?; E  [
; ?0 Z9 K$ P9 }4 N% k其中的寄生等效Diode會有Latch-up的問題。

. u+ T, u' ?1 }0 v) u% g. T這是製程受限的關係，比較先進的製程就沒這種問題了。

patrick02046

在EDA Board 抓的資訊， 參考一下:

I believe that what you are getting at is that there is a specific structure of P+/Nwell/Psub that is used for
5 ^$ h- U* m" A( e
7 w6 b; [' p: G3 @* U8 Uthe "bipolar", so you are asking why use that structure rather than simply a P+/Nwell "diode". Here is my take

; f; I) g" K) i) }on this:

9 K, e9 m) o- L1 z1- The "bipolar" will simulate more accurately than the "diode", since it will include the substrate current

" e$ F+ m# q0 M6 u" T! e& Fthat is probably not modeled for the "diode".
' g6 e& x2 ~) g# h: T: k; f, K
2- There usually is a specific structure for the "bipolar" that has characterization data available. When
. o( ]% q- P2 ^4 H' ^' @5 t
6 h0 e# P4 E, z8 g; o( k  w( pbuilding a bandgap structure, the good characterization is needed in order to properly determine the tempco of

the Base-emitter voltage.

! _( ?* J( @; V1 e& H6 y3- The additional structure of the bipolar should help prevent current injection into other substrate tied

7 \' a) v& J  c- G0 ]* ddevices.


/ y0 D: I& L" I# I8 A5 a6 _
There is, of course, nothing preventing the use of a P+/Nwell diode in your application.

luckyhuihui666

主要原因就是二极管不准确……