GaAs Crystal surface passivation method
AssigneeRockwell International Corporation
InventorsRanjeet K. Pancholy, Rene Drouet
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Abstract
Reheating the cooled wafer product of the known method of forming thermal oxide surface passivation layers on GaAs crystal wafers, i.e. heating the wafer in contact with thermally vaporized As.sub.2 O.sub.3 in a substantially oxygen free closed vessel at a reaction temperature in excess of 450 degrees, from a temperature lower than the reaction temperature to a temperature higher than the reaction temperature and in the presence of free oxygen increases the compositional, physical and electrical uniformity of the surface layer.
Claims13
A method of temporarily protecting a GaAs crystal wafer, which comprises heating the wafer in contact with thermally vaporized As.sub.2 O.sub.3 in a substantially oxygen free closed vessel at a reaction temperature in excess of 450 degrees Centigrade and for a time sufficient to surface react said As.sub.2 O.sub.3 with said wafer to form a passivation layer thereon of a first level of compositional and electrical uniformity;
- cooling said wafer below said reaction temperature;
- reheating the cooled wafer from a temperature lower than said reaction temperature to a temperature higher than said reaction temperature and in the presence of free oxygen, to improve layer compositional and electrical uniformity to a second higher level;
- and heating said wafer to a temperature sufficient to remove said thermal oxide surface passivation layer.
Dependencies are inferred from the claim text.