Uniform hot-wall MOCVD epitaxial growth of 2 inch AlGaN/GaN HEMT structures

Abstract

The hot-wall metalorganic chemical vapor deposition (MOCVD) concept has been applied to the growth of Al x Ga 1− x N/GaN high electron mobility transistor (HEMT) device heterostructures on 2 inch 4H-SiC wafers. Due to the small vertical and horizontal temperature gradients inherent to the hot-wall MOCVD concept the variations of all properties of a typical HEMT heterostructure are very small over the wafer: GaN buffer layer thickness of 1.83 μm±1%, Al content of the Al x Ga 1− x N barrier of 27.7±0.1%, Al x Ga 1− x N barrier thickness of 25 nm±4%, sheet carrier density of 1.05×10 13 cm −2±4%, pinch-off voltage of −5.3 V±3%, and sheet resistance of 449 Ω±1%.