DIFFUSED EMITTER AND BASE SILICON TRANSISTORS 



15 



4.1 Base Width 



From Fig. 8 and (4.3) it can be seen that for r2 ^ 10, a is essentially 

 independent of r2 and is primarily a function of T1/T2 and X. Fig. 9 is a 

 plot of a versus ri/r2 with X as the parameter. The particular plot is for 

 r2 = 10 . Although as stated a is essentially independent of r2 , at lower 

 values of r2, a may not exist for the larger values of X, i.e., the p-layer 

 does not form. 



In the same manner, it can be seen that ^ is essentially independent of 

 T]/T2 and is a function only of r2 and X. Fig. 10 is a plot of /3 versus F^ 

 with X as a parameter. This plot is for Ti/Fo = 10 and at larger Fi/Fo , 

 /3 may not exist at large X. 



10" 





\0' 



10 



1.0 



1.4 



1.8 



2.2 2.6 



a 



3.0 



3.4 



3.8 



Fig. 9 — Emitter layer thickness (in reduced units) as a function of the ratio 

 of the surface concentrations of the diffusing impurities (ri/r2) and the ratio of 

 their diffusion lengths (X). 



