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- From: LILMARA@YaleVM.YCC.Yale.Edu (Martin Lilly)
- Subject: Re: Lifetime of 25MHz IIsi (was: 25MHz IIsi and my engineering friend)
- Message-ID: <168A48EFD.LILMARA@YaleVM.YCC.Yale.Edu>
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- Organization: Yale University
- References: <1992Nov15.121708.24693@news.acns.nwu.edu> <STRANGE.92Nov15114832@squeeze.dec.com> <1992Nov16.163015.1763@udel.edu> <1992Nov16.181708.22881@news.uni-stuttgart.de>
- Date: Thu, 19 Nov 92 10:09:58 EST
- Lines: 21
-
- In article <1992Nov16.181708.22881@news.uni-stuttgart.de>
- skok@itwds1.energietechnik.uni-stuttgart.de (Holger Skok) writes:
-
- >>"The candle which burns twice as bright burns half as long."
- >
- >(discussion about heat deleted)
- >It's diffusion that kills the CPU. All those nifty PN or other junctions
- >tend to even out over time. The concentration of the donor and acceptor
- >alloying (dotation ?) materials is different on the different sides of
- >the junctions which amounts to a driving potential for diffusion. The
- >coefficient of molecular diffusion is temperature dependent - it is
- >higher at higher temperatures. Conclusion: the higher the temperature
- >the faster all concentration differences in the IC even out, thereby
- >destroying it.
- >
- My P-chem text says that diffusion is a function of temperature in degrees
- Kelvin. Even if the cpu is running 50 degrees hotter- which it won't with a
- heat sink installed -is there a big difference between 400 and 450 degrees K?
- Any physicists out there to comment?
-
-
-