EARLY TRANSISTOR HISTORY AT

TEXAS INSTRUMENTS 

Mary Anne Potter

 

Oral History – Mary Anne Potter

(Continued)

 

Of course, the tubes that were inside the furnaces were also made from quartz. TI had a large internal “glass” blowing business where all the quartz work was done. Several of the more experienced glass blowers took vacation time during the state fair to perform their magic at the fair. They were very accomplished. I think they made more money at the fair in two weeks than they did in several months at TI.

 

I remember well one of our more “interesting” failures.  It will give you a good idea of the complexity of the production processes we were working with in the early days.  This situation related to our trying to qualify a better source for generating the P-type bases for all of the ICs.

 

Tests had been done in the pilot line that proved that this source produced much better controlled surface concentrations with none of the messy problems the boron tribromide source caused. BBr3 is a very bad liquid that can burn through a thick rubber glove in seconds. It also caused a sticky build up inside the quartz tubes that caused us to have to clean them quite often, and it frequently caused a boron “skin” that even 100% HF could not remove. This was especially true for the P-type emitters that the quad-diffused structures had to have.

    

 

 

 

 

 

 

 

 

 

Oral History – Mary Anne Potter

(Continued)

 

The new process was going to be very costly to implement because it required that the slices all be enclosed in a platinum diffusion box with a platinum lid. I don’t remember why this was as I did not develop the process, but I did run tests for the quad-diffused products and was very impressed.

 

Anyway the product engineers all did cost analyses with breakeven calculations based on the increased yields with better control of our boron processes and convinced management to allow us to convert production to this superior process. Since the production area had furnaces with longer usable boat lengths, the production boats were quite a bit bigger than those used in the pilot line. The quartz carriers for the slices were also quite intricate, so it took several months to obtain the platinum boxes and lids and the quartz carriers.

 

Finally production was ready to go. We ran the first test to be sure we could duplicate the results. I think we actually loaded the carriers and supervised the test. All was well, and we turned production on for all three shifts. We thought this would be a great success, and we could then move on to the next set of problems.  Unfortunately, we had problems right away - the boron process was in bad shape!

 

 

  Potter Oral History, Page 7

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