Patent ID: 8025729
Filing Date: 2011-09-27
Classification: C30B,H01L,Y10T

Abstract:
1. A process for heat treating at an increased temperature a wafer comprising, at least at a surface thereof, a semiconductor material comprising GaAs, the wafer having a diameter of ≧100 mm, wherein the process comprises: placing one or more wafers having a diameter of ≧100 mm in an interior space of a heating furnace or container; heating the wafer at an increased temperature without applying As partial pressure from the outside, under a condition wherein a limited gas exchange is ensured between the surface of the wafer to be heat treated and the interior space of the heating furnace or container, such that precipitates of the As component are reduced in size and/or density in a surface layer of the GaAs semiconductor material-comprising surface of the wafer, wherein the precipitates reduced in size and/or density in said surface layer are defined by a lpd value of lower than about 50 cm wherein the limited gas exchange is defined to be substantially lower than an unhindered free gas exchange between the surface of the heat treated wafer and the interior space of the heating furnace or container, but gas exchange is allowed by exceeding a hermetical sealing of the surface of the heat treated wafer.