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
  _& u; y/ r8 ^) z無法做出二極體, 只能用寄生的
* i1 N( c  J' Wvertical PNP呢???

leo911759

其實也是有的。

有一些Paper就是用Diode，或是NPN。
/ _6 n& ~: Y9 B! t! t. {5 k2 W
. E6 y) V2 f- r, [+ c" ]而會用PNP 是因為早期CMOS製程中，只能寄生等效PNP電路。

, r3 J# j9 d1 ]其中的寄生等效Diode會有Latch-up的問題。
- U" c; v+ l% I
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:

0 a! E0 t7 x* K7 i6 `, mI believe that what you are getting at is that there is a specific structure of P+/Nwell/Psub that is used for
* X" M8 L- V1 O# n/ E( J
- R4 ?7 w' r" K4 Z; zthe "bipolar", so you are asking why use that structure rather than simply a P+/Nwell "diode". Here is my take

$ T& W! P% [0 I1 @3 [on this:

1- The "bipolar" will simulate more accurately than the "diode", since it will include the substrate current
3 t: B7 b( H1 U3 [8 I3 r- o
that is probably not modeled for the "diode".

2- There usually is a specific structure for the "bipolar" that has characterization data available. When
. ~+ M( o* C4 b
- U  k3 p% o- B9 r. sbuilding a bandgap structure, the good characterization is needed in order to properly determine the tempco of
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the Base-emitter voltage.

3- The additional structure of the bipolar should help prevent current injection into other substrate tied
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devices.

) i7 L( N0 I) @9 z; Y2 E

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……