Diffused p-n Junction Silicon Rectifiers 



By M. B. PRINCE 



(Manuscript received December 12, 1955) 



Diffused p-n junction silicon rectifiers incoryorating the feature of con- 

 ductivity modulation are being developed. These rectifiers are made by the 

 liiffusion of impurities into thin wafers of high-resistivity silicon. Three 

 \ development models with attractive electrical characteristics are described 

 irhich have current ratings from to 100 amperes with inverse peak voltages 

 qreater than 200 volts. These devices are attractive from an engineering stand- 

 point since their behavior is predictable, one process permits the fabrication 

 of an entire class of rectifiers, and large enough elements can be processed 

 so that power dissipation is limited only by the packaging and mounting 

 ■of the unit. 



l.n INTRODUCTION 



1.1 The earliest solid state power rectifier, the copper oxide rectifier, 

 was introduced in the 1920's. It found some applications where effi- 

 ciency, space, and weight requirements were not important. In 1940 

 the selenium rectifier was introduced commercially and overcame to a 

 great extent the limitations of the copper oxide rectifier. As a result, 

 the selenium rectifier has found wide usage. In early 1952 a large area 

 licrmanium^ junction diode was announced which showed further im- 

 ' provements in efficiency, size, and weight. In addition it shows promise 

 of greater reliability and life as compared to the earlier devices. How- 

 ever, all of these devices have one drawback in that they cannot operate 

 111 ambient temperatures greater than about 100°C. 



Also in 1952, the silicon alloy^ junction diode was announced and was 

 shown to be capable of operating at temperatures over 200°C. However 

 it was a small area device and could not handle the large power that the 

 other devices could rectify. During the past three years development 

 has been carried on by several laboratories in improving the size and 

 power capabilities of these alloy diodes. In early 1954 the gaseous diffu- 



' Hall, R. N., Proc. I.R.E., 40, p. 1512, 1952. 



2 Pearson, G. L., and Sawyer, B., Proc. I.R.E., 40, p. 1348, 1952. 



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