CDHWilli@exua.exeter.ac.uk (Charles Williams) (05/28/91)
Feel free to flame me if this is a FAQ, but tell me where the FAQ list is first! Tunnel diodes are of interest to me because they should work okay at low temperatures (ie 4K). However I'm having difficulty finding anywhere that still makes/supplies them. Can anyone help with manufacturers please? Email to me and I'll summarise and post. Thanks in advance. C.D.H.Williams@exeter.ac.uk
ornitz@kodak.kodak.com (Barry Ornitz) (06/04/91)
In article <CDHWILLI.91May28174423@exua.exua.exeter.ac.uk> CDHWilli@exua.exeter.ac.uk (Charles Williams) writes: >Feel free to flame me if this is a FAQ, but tell me where the FAQ list is >first! Tunnel diodes are of interest to me because they should work okay at >low temperatures (ie 4K). However I'm having difficulty finding anywhere that >still makes/supplies them. Can anyone help with manufacturers please? This is not a frequently asked question. In fact, I asked something similar last year. A number of "older" net readers were familiar with tunnel diodes. A few kind souls even offered to open their "junque" boxes and give me a few! [My application was a business one, so I did not take them up on their offers. These folks were real gems; I was quite grateful for their offers.] Many of the younger folks in sci.electronics, those reared on micros, had never heard of tunnel diodes. In any event, I was only able to find one US manufacturer of tunnel diodes: Custom Components, Inc. They make a full line of germanium and gallium arsenide devices, from amplifier diodes, to detector diodes, to oscillator diodes, to switching diodes, to Schottky mixer diodes, to special microwave devices, and to conventional back diodes. They continue to supply all of the GE tunnel diode devices from the 1960's too. Their prices are not very different from the 1960's prices for tunnel diodes either. If you call them, ask for Charles Blaine for technical questions. Their full address is: Custom Components, Inc. P. O. Box 334 Lebanon, New Jersey, 08833 USA 201/534-6151 201/534-5625 (facsimile) Good luck with your project. Barry ----------------- | ___ ________ | Dr. Barry L. Ornitz WA4VZQ | | / / | | Eastman Kodak Company | | / / | | Eastman Chemical Company Research Laboratories | |< < K O D A K| | Process Instrumentation Research Laboratory | | \ \ | | P. O. Box 1972, Building 167B | |__\ \________| | Kingsport, TN 37662 615/229-4904 | | INTERNET: ornitz@kodak.com -----------------
ee5391aa@triton.unm.edu (Duke McMullan n5gax) (06/04/91)
In article <CDHWILLI.91May28174423@exua.exua.exeter.ac.uk> (Charles Williams) writes: >Feel free to flame me if this is a FAQ, but tell me where the FAQ list is >first! Tunnel diodes are of interest to me because they should work okay at >low temperatures (ie 4K). However I'm having difficulty finding anywhere that >still makes/supplies them. Can anyone help with manufacturers please? Hmmm...try one of the wide-spectrum catalogs like Newark. AMTRAK uses a lot of the things to prevent head-ons in their tunnels.... d
tk@wheat-chex.ai.mit.edu (Tom Knight) (06/05/91)
What makes you believe that tunnel diodes will work at 4K? I would guess that carrier freezeout would start being a significant effect at about 25K and would be near complete at 4K. KT at T=4K is approximately 3e-4 ev and the ionization energy of typical dopants is more like 4.5e-2 ev, so you would guess that a fraction of about 1e-150 would be ionized (i.e. none). Perhaps you are thinking of Josephson junctions, which are made with metal/oxide/metal sandwiches, and don't need to be doped.
henry@zoo.toronto.edu (Henry Spencer) (06/05/91)
In article <16303@life.ai.mit.edu> tk@wheat-chex.ai.mit.edu (Tom Knight) writes: >What makes you believe that tunnel diodes will work at 4K? I would >guess that carrier freezeout would start being a significant effect at >about 25K and would be near complete at 4K... I would also predict some problems with differential thermal contraction causing cracking of package, chip, and/or leads well before then. Back when IBM was working on Josephson-junction computers, they put quite a bit of effort into the problem of building circuit assemblies that could go from room temperature to cryogenic temperatures and back repeatedly and remain reliable. -- "We're thinking about upgrading from | Henry Spencer @ U of Toronto Zoology SunOS 4.1.1 to SunOS 3.5." | henry@zoo.toronto.edu utzoo!henry
CDHWilli@exua.exeter.ac.uk (Charles Williams) (06/07/91)
In article <16303@life.ai.mit.edu> tk@wheat-chex.ai.mit.edu (Tom Knight) writes: >What makes you believe that tunnel diodes will work at 4K? I would >guess that carrier freezeout would start being a significant effect at >about 25K and would be near complete at 4K... You *are* guessing. See for example B. Lengeler, Cryogenics 14 (1974) pp439-447 In article <1991Jun5.163259.1228@zoo.toronto.edu> (Henry Spencer) says: >I would also predict some problems with differential thermal contraction >causing cracking of package, chip, and/or leads well before then. Back >when IBM was working on Josephson-junction computers, they put quite a >bit of effort into the problem of building circuit assemblies that could >go from room temperature to cryogenic temperatures and back repeatedly >and remain reliable. Thermal contraction can be a problem, but not always. A reasonably recent review with 82 exciting references is RK Kirshman, Cryogenics 25 (1985) pp115-122 BTW a Josephson version of the Am2901 4-bit Microprocessor has been protyped by Fujitsu using Nb-AlOx-Nb technology. Comparative performance: Material Clock (MHz) Power dissipation (W) -------- ----------- --------------------- Si 30 1.4 GaAs 72 2.2 Josephson 770 0.005 But that was over a year ago now..... Charles Williams.