Control of Thickness and Composition Variation of AlGaN/GaN on 6- and 8-in. Substrates Using Multiwafer High-Growth-Rate Metal Organic Chemical Vapor Deposition Tool

Abstract

It is difficult to control the surface temperature gradient over a bowing GaN on a large-diameter silicon substrate by metal organic chemical vapor deposition (MOCVD) because the wafer bows convexly to store compressive strain during growth. In an attempt to grow uniform AlGaN/GaN on 6-in. (6'') silicon substrates using a 7×6'' reactor, we described in this paper the control of the surface temperature gradient over the wafer and the mass transport at the edge of the wafer. We attempted to grow Al0.23GaN/AlN/GaN/SLS/Al0.5GaN/AlN on six 8-in. (8'') silicon substrates using a 6×8'' reactor. The standard deviations of total thickness were less than 2.0% on wafer and 0.31% wafer to wafer. The growth rate of strained-layer superlattice (SLS) was as high as 2.8 µm/h. The typical electron mobility was 1670 cm2·V-1·s-1 at a sheet carrier density of 1.11×1013 cm-2.