Radiation effects on 2n2222 or similar

one of the other unfortunate take-aways from the final paper is that damage profile can apparently vary widely even among the same generic type from different manufacturers.

Placing the working unit (open base) in a very high dose area for 2 months, where it will see approximately a rate of approximately 15 Rem/hour. Not steady state, but plenty every day.

In the Apollo daze, some data may have been collected concerning this question (uA709 W-stepping, input pair).

Is there any data concerning E-B zener voltage changes, and is there any material difference WRT transistor type (say 2N3904)?

Thanks.

What's a convenient way to get a "high dose area"? When in college (long ago) I had ready access to a nuclear reactor, and all kinds of sources, but ...

David Hahn used smoke alarms for alphas. An x-ray tube is also possible.

Part of the takeaway from this paper I posted from the 90s seems to be that performance can vary widely even among devices of the same generic type because it's highly dependent on emitter geometry/construction (does base metallization pass over the emitter-base region in a given jellybean? sometimes yes and sometimes no apparently, there's no "reference topology" as it were for those parts) and different manufacturers have different ways of doing things.

or even the same manufacturer uses somewhat different geometries and construction on different runs. They're cheap parts they prolly press into service whatever slack capacity they have at a given time with whatever process the plant that's slack happens to be set up for, I don't think e.g. Fairchild has dedicated lines to cranking out jellybean

There may be data on what particular mfgr as of 2019 makes the most resilient jellybeans off-the-shelf, it sounds like kind of info that perhaps reads class-i-fied

There's not a lot of consistency; a different metallization may cause an X-ray fluorescence, so the KIND of radiation matters as much as the ion-pair-production Rem number.

I think the Apollo program used uA702. The uA709 came too late?

piglet

Answering myself: the uA709 was indeed used in some of the later lunar surface science packages. Makes sense as it was much nicer to use :)

piglet

When in college (long ago) I had ready access to a nuclear reactor, and all kinds of sources, but ...

Got a friend in the nuclear medicine field?

You might also check some amateur radio AMSAT groups. They build satellites and especially those satellites with highly elliptical Molnya orbits cross the VanAllen radiation belts twice in an orbit, four times a day. Check what components they are using.

Hi, Win:-

A few years ago I did some rad testing for a potential deep space project- we used the TRIUMF particle accelerator facility in BC.

The beam current was set by calling into the control room IIRC (single digit nA) and you cooked the circuit for as long as you wanted to get the integrated dosage. I ran long cables out of the high radiation area for monitoring (and power control in case something glitched). A few PCs, a bunch of remotely controlled power supplies and test equipment etc. Took that all in airline baggage.

Our tests were slotted around some Intel and IBM greybeards who were dealing with some advanced processor.

You do a safety course and briefing and so on, as you might expect.

--Spehro Pefhany

Trivially, I would expect the metal-can 2222A to be better than 3904.

Some radiation may get transformed in the metal-can into a shower of lower-energy particles with more effect in silicon. So it will depend.

The main invariant characteristic was that devices with higher than average B-E operating current densities at both ends of their specified conditions were more intrinsically hard than others, e.g. the 2N914 as an example of a more resistant device.

that is to say it's better to have a larger P/A ratio plus a higher average current density and, up to a point, somewhat smaller volume BE junction than a smaller P/A ratio, lower current density and larger volume.

the area decreases as the square but the volume decreases as the cube so up to a point the absorbed dose becomes less because it's a harder target to "hit." then past that point as the volume decreases further the damage factor goes up again because what impacts there are hurt the more fragile small junction a lot more.

I may not have that correct please correct if one can explain the physics better

Am 29.06.19 um 08:23 schrieb Robert Baer:

That is not a direct answer to your question, but nevertheless interesting and in the field.

Cheers, Gerhard

Yes, exactly: high energy gammas that go through silicon without harm can hit a gold-plate (or Ni or Cu or Fe) material and make few-kV X-ray fluorescence that dumps all its energy in a millimeter of Si.

Only thing is "modern processes" for olde/vintage semis is process cleanliness is better and purities may be better. So if manufacturer kept the basic process, part "sensitivity" will remain the same.

Wide variations of even a "simple" part like a 2N2222 seem to have been a tour-de-force for ages. Even from the SAME manufacturer over time (different fabs used, different "formulas", different diffusion containers:new vs used). Ain't no sech ting as a "standard".