992 



THE BELL SYSTEM TECHNICAL JOURNAL, JULY J 957 



respectively. The circles represent measured points and the solid lines 

 are the calculated theoretical curves. It is observed that the fit in Fig. 

 9 is quite good; whereas, the fit in Fig. 10 is not as good as at the other 

 temperatures. However, even this figure shows good quahtative agree- 

 ment of the deviation from a straight line. Some of the factor of two dis- 

 crepancy in Fig. 10 can be ascribed to the temperature variation of the 

 other parameters, and some to a possible error in the measurement of 

 temperature which would be reflected in the value of rii . 



It should be noted that at all temperatures the IR drop in the high 

 resistivity region is not observable to the limits of the experimental 

 measurements of forward current, 10 milliamperes. This is due to the 

 fact that the region has been conductivity modulated by the forward 

 current. This requires a sufficient minority carrier lifetime in the region 

 so that most of the injected carriers diffuse across the region before re- 

 combming. Such lifetimes can be maintained in diffused junctions 



10-' 

 5 



10-2 

 5 



IQ-^ 



OJ 

 Q. 



< 



-10" 



cr 



ct 



D 

 U 



10- 



10'^ 

 5 



10" 



0.3 0.4 0.5 0.6 0.7 



V IN VOLTS 



0.8 



0.9 



Fig. 10 — The calculated and observed current -voltage characteristic of a 

 forward biased junction at 220° K. 



