DIFFUSED EMITTER AND BASE SILICON TRANSISTORS 



AU-Sb PLATED 

 POINT 



VAPORIZED Al 



LINE 

 0.005 CM WIDE 



t MM 



Fig. 3 — Mounted double diffused transistor. 



Contact to the emitter layer is achieved by alloying a film of gold 

 containing a small amount of antimony. Since this alloy will produce 

 an n-type regrowth layer, it is only necessary to insure that the gold- 

 antimony film does not alloy through the p-type base layer, thus shorting 

 the emitter to the collector. This is controlled by limiting the amount of 

 gold-antimony alloy which is available by using a thin evaporated film 

 or by electroplating a thin film of gold-antimony alloy on an inert metal 

 point and alloying this structure to the emitter layer. 



Ohmic, contact to the collector is produced by alloying the silicon 

 wafer to an inert metal tab plated with a gold-antimony alloy. 



