Verfahren zum Herstellen eines nichtwasserloeslichen UEberzuges aus Germaniumoxyd an der Oberflaeche eines Germaniumkristalles

A germanium crystal is provided with a protective layer of tetragonal germanium dioxide by oxidizing its surface by heating in a liquid containing hydroxyl groups under a pressure of at least 5 atmospheres and preferably of 30 atmospheres or more. Suitable liquids include water and alcohol and heating is carried out at temperatures above 150 DEG C. Pressurization may be by ram pressure or by gas, or be produced solely by the vapour pressure of the liquid. Etching of the germanium crystal before formation of the oxide layer may be avoided by dissolving hexagonal germanium dioxide, which in contrast to tetragonal dioxide is soluble in water to saturation in the liquid before inserting the germanium crystal.ALSO:A germanium crystal is provided with a protective layer of tetragonal germanium dioxide by oxidizing its surface by heating in a liquid containing hydroxyl groups under a pressure of at least 5 atmospheres and preferably of 30 atmospheres or more. Suitable liquids include water and alcohol and heating is carried out at temperatures above 150 DEG C. Pressurization may be by ram pressure or by gas, or be produced solely by the vapour pressure of the liquid. Etching of the germanium crystal before formation of the oxide layer may be avoided by dissolving hexagonal germanium dioxide, which in contrast to tetragonal dioxide is soluble in water, to saturation in the liquid before inserting the germanium crystal.