2N2369 reverse Vbe avalanching, consequences?

Oops, sorry, I meant in the collector. The emitter is on ground. Other than the transistor capacitances itself there's less than 2pF connected.

--
Regards, Joerg 

http://www.analogconsultants.com/

However, supposedly it worked. I don't remember wether it was Camel or Marlboro :-)

--
Regards, Joerg 

http://www.analogconsultants.com/

Why are we talking about gold? There's lots of other atoms, I see no reason to identify the reverse-bias of base/emitter with a gold migration.

IIRC the transistors in the HP gear where the cigarette extinguishing trick worked were fairly regular ones and unlikely gold-doped.

--
Regards, Joerg 

http://www.analogconsultants.com/

It's a gold-doped device... specifically done to decrease recovery time. You don't know about gold-doped transistors? ...Jim Thompson

--
| James E.Thompson                                 |    mens     | 
| Analog Innovations                               |     et      | 
| Analog/Mixed-Signal ASIC's and Discrete Systems  |    manus    | 
| San Tan Valley, AZ 85142     Skype: skypeanalog  |             | 
| Voice:(480)460-2350  Fax: Available upon request |  Brass Rat  | 
| E-mail Icon at http://www.analog-innovations.com |    1962     | 
              
I love to cook with wine.     Sometimes I even put it in the food.

2N2369 IS gold-doped... I know it well... used it often in the 1977-1987 time-frame in OmniComp/GenRad products. ...Jim Thompson

--
| James E.Thompson                                 |    mens     | 
| Analog Innovations                               |     et      | 
| Analog/Mixed-Signal ASIC's and Discrete Systems  |    manus    | 
| San Tan Valley, AZ 85142     Skype: skypeanalog  |             | 
| Voice:(480)460-2350  Fax: Available upon request |  Brass Rat  | 
| E-mail Icon at http://www.analog-innovations.com |    1962     | 
              
I love to cook with wine.     Sometimes I even put it in the food.

Any chance of changing that to 100k base, or 1k collector? Equal values (assuming equal voltages, anyway) suggest hFE = 1 and potentially microseconds of storage. Could also strap a small cap (100pF?) across the base resistor.

If the current has to be small, a smaller RF transistor will be the next best, like I said.

Tim

--
Seven Transistor Labs, LLC 
Electrical Engineering Consultation and Contract Design 
Website: http://seventransistorlabs.com

I know it is gold-doped. All I am saying is that AFAIR there was not a

2N2369 in that instrument, at least not in the input stage.

--
Regards, Joerg 

http://www.analogconsultants.com/

I suggest that you zener a few transistors, different measured "levels" of dosage (label and document). Then try the bake for (am guessing) 1-2 hours and re-measure. Ain't dopant" migration".

Correct,but the symptoms are rather similar and the cure is the same.

AFAIK gold was used in some linear parts (around 40 years ago) to speed them up (UA710, UA71 fer eggzample). Slightly aged technology...

Your beard is getting white...

Gee, that was yesterday...

Or, be CHIPper...no case at all.

No, I don't. How does the gold help? Does it increase the e-h recombination? By creating states in the gap maybe??

George H.

I wondered the same as you, George. I found this out:

Seems Hoerni developed gold-doping at Fairchild in mid-1959. The effect is to provide localized sites for hole recombination. In practice the downsides are increased forward voltage drop and increased leakage current. A lot of the fast p-n "logic" diodes like 1N914 are Au-doped. It works in germanium too.

and from:

IEEE Transactions on Electron Devices (Impact Factor: 2.36). 01/1977; ED-23(12):1279 - 1283. DOI: 10.1109/T-ED.1976.18650

I got this abstract:

"ABSTRACT Both platinum and gold have been used to reduce lifetimes in fast recovery silicon power devices. There are substantial differences between the energy levels introduced by these impurities. Both impurities introduce acceptor levels which act to reduce hole lifetimes in n-type silicon; however, the gold acceptor is much deeper (E c - 0.54 eV) than the corresponding platinum acceptor (E c - 0.26 eV). In p-type material, on the other hand, the two impurities are quite similar; gold introduces a donor at E v + 0.35 eV, while the platinum donor is at E v

• 0.32 eV. In terms of basic physics, this paper establishes guidelines to determine, for a given device type, which lifetime killer should be used to provide optimal performance. Platinum offers improved high-temperature properties and turn-on performance when compared to gold and is a better selection for devices which are switched so rapidly that the turn-off is governed mainly by the high injection lifetime. However, when the switching wave form involves low injection recombination tails, gold is a better choice than platinum. "

regards piglet

Yup.

Cheers

Phil Hobbs

Been that way for years. ...Jim Thompson

--
| James E.Thompson                                 |    mens     | 
| Analog Innovations                               |     et      | 
| Analog/Mixed-Signal ASIC's and Discrete Systems  |    manus    | 
| San Tan Valley, AZ 85142     Skype: skypeanalog  |             | 
| Voice:(480)460-2350  Fax: Available upon request |  Brass Rat  | 
| E-mail Icon at http://www.analog-innovations.com |    1962     | 
              
I love to cook with wine.     Sometimes I even put it in the food.

My MC4024 Voltage-Controlled Multivibrator was run on a gold-doped TTL process so I could get a TTL-compatible output stage... the rest of the chip is essentially all current-mode. ...Jim Thompson

--
| James E.Thompson                                 |    mens     | 
| Analog Innovations                               |     et      | 
| Analog/Mixed-Signal ASIC's and Discrete Systems  |    manus    | 
| San Tan Valley, AZ 85142     Skype: skypeanalog  |             | 
| Voice:(480)460-2350  Fax: Available upon request |  Brass Rat  | 
| E-mail Icon at http://www.analog-innovations.com |    1962     | 
              
I love to cook with wine.     Sometimes I even put it in the food.