Re: CHIP SUBSTRATE
Hello!
Why do we always use P-sub instead of N-sub?
What are its pros and cons?
Any idea would be greatly appreciated.
thanks in advance.
regards.
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Substrate normally doped to be p -type for a number of reasons
In CMOS circuits the n-well and the p-substrate form a diode. This helps prevent latch up.
Substrate is resistive
Lightly doped - High resistance- useful in analog applications where noise isolation is important
Heavily doped - low resistance- useful in large scal digital where latch up may be an issue.
P -type is cheaper to make and easier to fabricate.
I can add more later once Ive finished my power point slides....68 so far!