INORGANIC REPLICATION IN ELECTRON MICROSCOPY 



815 



evaporated; the films are substantially amorphous; they are fully as rugged 

 as silica films in processing and, in contrast to silica films, are easily seen 

 during the "fishing" part of this procedure. Because they are conducting 

 and do not tend to charge up in the microscope, germanium films are more 

 stable than sihca. Finally, and most important, because germanium is 



^ 



Fig. 14 — Germanium replica (h ~ 150A, da = 35°) of near optimum thickness. Resolu- 

 tion about 75A. Ruptured film evident in shadow. 



twice as dense as siHca, the intrinsic resolution (Table I) is better by a factor 

 of two. Many of these remarks apply also to chromium and gold-manganin 

 replicas; however, they are not amorphous and are less rugged in processing, 

 even though they are perhaps even more stable in the microscope. Stereo- 

 scopic pairs from germanium replicas are not shown only because it is 

 desired to present the more extensive enlargements of Figs. 13 and 14. 



