Thickness dependence of material quality in GaAs-on-Si grown by metalorganic chemical vapor deposition

Abstract
The evolution with increasing layer thickness of the structural and electrical properties of GaAs grown directly on Si or Si‐on‐insulator (SOI) by metalorganic chemical vapor deposition is reported. There is a substantial improvement in the surface morphology and near‐surface crystallinity of the GaAs in thicker films (≥1.5 μm). The implant activation efficiency of 60‐keV 29Si ions at a thickness of 4 μm is comparable to that seen in bulk GaAs. The deep level concentration is also observed to decrease with increasing layer thickness. Transmission electron microscopy reveals average defect densities near 108 cm2 in films deposited either on misoriented or exact (100) Si, and in those grown on SOI.