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
無法做出二極體, 只能用寄生的
' u3 Q) C6 J  X5 w* N( S+ pvertical PNP呢???

leo911759

其實也是有的。
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有一些Paper就是用Diode，或是NPN。
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8 L. U+ j1 x% t3 T! P( S& Y而會用PNP 是因為早期CMOS製程中，只能寄生等效PNP電路。
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! H; @4 D, E% e  D/ h- I其中的寄生等效Diode會有Latch-up的問題。

, Y% ~8 i1 j% E9 o6 ?) _. 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:
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I believe that what you are getting at is that there is a specific structure of P+/Nwell/Psub that is used for
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the "bipolar", so you are asking why use that structure rather than simply a P+/Nwell "diode". Here is my take
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on this:
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+ H. W( h; Q0 e1- The "bipolar" will simulate more accurately than the "diode", since it will include the substrate current
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$ H  ^$ q, A7 M8 o( Wthat is probably not modeled for the "diode".

0 x' G4 v% ]" y7 I2- There usually is a specific structure for the "bipolar" that has characterization data available. When

; _( f5 M& [; z& Zbuilding a bandgap structure, the good characterization is needed in order to properly determine the tempco of

the Base-emitter voltage.
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" g; U3 m8 O  V+ w+ H3- The additional structure of the bipolar should help prevent current injection into other substrate tied

devices.

2 P( d* s) b) ]* h. ~/ R

; q5 @5 t8 y. l( C" V# kThere 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……