DIFFUSED p-n JUNCTION SILICON RECTIFIERS 



671 



assemlily into the mechanical package designed for a given current 

 rating. 



4.3 The dice may be tested electrically before assembly by using 

 pressure contacts to either side. Pressure contacts have been considered 

 for packaging the units; however, this type of contact was dropped from 

 development due to mechanical chemical, and electrical instabilities. 



4.4 The drawbacks of the pressure contact make it important to find 

 a solder contact that does not have the same objections. The solder used 

 should have a melting point above 300°C, be soft to allow for different 

 coefficients of expansion of the silicon and the copper connections, wet 

 the plated metal, and finally, be chemically inactive even at the high 

 temperature operation of the device. These recjuirements are met with 

 many solders in a package that is hermetically sealed. This combina- 

 tion of a solder and a hermetically sealed package has been adopted for 

 the intermediate development of the diffused silicon power rectifiers. 



5.0 ELECTRICAL PERFORMANCE CHARACTERISTICS 



5.1 Before describing the electrical properties of these diodes, let us 

 consider some of the physical properties of a few members of the class. 



r~=^^T:) 



SMALL 

 0-1 AMPERES 



MEDIUM 

 1-10 AMPERES 



LARGE 

 10-100 AMPERES 



Fig. 6 — Development silicon rectifiers. 



