Germanium surface damage

Electron spin resonance lines associated with mechanical surface damage have been observed by Fletcher et al (38) and Feher (39) in silicon, and by Walters (40) in germanium. Feher... 

Sullivan and Eigler (42) developed a technique for removing the damaged surface layer from the p-n junction area of germanium diodes without masking. The germanium diode is placed inside a hairpin-shaped platinum cathode and a stream of 0.1% KOH is allowed to flow down between the cathode and the germanium. Surface tension confines the electrolyte to the junction area. A polished surface is usually completed in 1 to 2 min at 1. 5 amp/cm. ... 

This is illustrated in Fig. 1 the oxidation was carried out at a pressure of approximately 10" mm and at 900°C, at this temperature the oxide is volatile thus a pit is formed. Fig. 2 shows oxidation at a similar pressure on ill material although there are fewer oxidation pits in this picture, they are not found at dislocation sites. Oxidation in concentrated nitric acid had the advantage that the oxide layer left by the CP4 etch that was used to remove the damaged layer could be removed by HF. Many more oxide particles were formed on surfaces that did not have this oxide layer removed prior to oxidation. Thus we can say, at least for germanium, that the dislocations do not act as preferential sites for the nucleation of oxidation. 

In one of the earliest studies of abrasion damage Clarke and Hopkins (25, 26) found that sandblasting germanium produced a surface layer of relatively high p-type conductivity. The... 

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