PROPERTIKW ()p^ IONIC HOMHAKDKD .SILICON 111 



from a comparison of Fi^. 3a with Fi^. 31) that at the one volt level, the 

 ratio of forward to reverse currents for the unhomharded case is about 

 twenty, whereas that for the boml)ard('(l case, is more than 1(),()0(). At 

 oth(M' levels the difference is even <2;i'(^J>ter. Referring particularly to Figs. 

 3c and 3d, it will be seen that one effect of bombardmcMit is that of 

 separating the two significant points of inflection B and C. That is, the 

 inflection interval has been notably incn^ased. This increase is the result 

 of a small increase in the forward voltage and a very substantial increase 

 in the reverse voltage. 



EFFECT OF TYPE OF GAS 



Four high purity gases were tested as ion sources, namely, hydrogen, 

 helium, nitrogen and argon, having atomic weights respectively of 1, 4, 



-5 5 -10 -5 5 

 (a) UNTREATED (b) HYDROGEN 



-15 -10 -5 



VOLTAGE 

 (c) HELIUM 



-10 -5 ; 

 (d) NITROGEN 



-10 -5 5 

 (e) ARGON 



,0-7 2 4 6 a,Q-6 2 4 6 8,^-5 2 4 6 8,^-4 2 4 6 8,^-3 2 4 6 8,0-2 2 



CURRENT IN AMPERES 



Fig. 4 — Characteristics stiowing eti'ect of various gases all with a l)ombarciing 

 potential of 30 kv. 



