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
  \- S9 T$ d+ i9 j7 O) T2 O無法做出二極體, 只能用寄生的
" ?! ^  N# [1 U& g2 uvertical PNP呢???

leo911759

其實也是有的。

有一些Paper就是用Diode，或是NPN。

! p& j, p9 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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/ m2 u; b% N# m8 Q# O  b9 s! W. K7 j. n其中的寄生等效Diode會有Latch-up的問題。
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; Y- Q2 v7 i4 v" e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
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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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+ M; g) [1 L% c; Pon this:

1- The "bipolar" will simulate more accurately than the "diode", since it will include the substrate current

that is probably not modeled for the "diode".
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2- There usually is a specific structure for the "bipolar" that has characterization data available. When
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building 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.


) L# D+ X0 R7 L& J2 g
0 w7 }/ F5 k( d; N* R( h9 K; ~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……