[sdiy] Cryogenic Synthesizer Construction?

[Martin Czech]

No. Even automotive or military semiconductors are speced to a lower
limit of -50C. Liquid nitro is cooler I guess. You're way out of spec.
The problem is that if you dope Si at room temperature, all donators or
acceptors will do their job, create electrons and holes.  That's why
semiconductors conduct current.  If you cool it, you will have less
carriers. semiconductors for low temperatures exist, I guess the low
temp operation is balanced by raised dope levels.

And you induce a lot of mechanical stress, because Si shrinks
different from Si02, and plastic, and copper leadframes.
So, cooling that way is a good idea to destroy a chip by nice
cracks. We call this "temperature shock test".
Boiling oil and then back to some cooling "freon".
Slower cooling will not help much.

Cooling a bad resistor won't help much, because 1/f doesn't resond
to temperature.

m.c.



:::X-Authentication-Warning: node12b53.a2000.nl: majordomo set sender to 
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:::X-Sender: mclilith at mail.ezwv.com
:::Date: Wed, 21 Feb 2001 01:14:40 -0500
:::To: synth-diy <synth-diy at node12b53.a2000.nl>
:::From: Glen <mclilith at ezwv.com>
:::Subject: [sdiy] Cryogenic Synthesizer Construction?
:::
:::At 11:08 PM 2/20/01 , harry wrote:
:::>If we just dipped it in liquid nitrogen... would some of the effect be
:::>permanent ? 
:::
:::Okay, I know we are just kidding about the liquid nitrogen treatment, but I
:::have a couple questions. If one were to chill typical analog audio
:::circuitry with liquid nitrogen, would it continue to actually function at
:::such low temperatures?
:::
:::I assume that residual noise levels would be noticeably reduced, (assuming
:::the circuit still functions), but what other effects might there be? Does
:::anyone actually know?
:::
:::I suppose it might be one (expensive) way to attack the problem of drifting
:::synth oscillators.   :)
:::
:::
:::Later,
:::Glen