Growth and structural properties of GaAs on Al pseudo-substrates for ultrafast optoelectronics

GaAs is broadly used in modern electronics. On the other hand, application of GaAs-based devices in high power electronics is complicated due to the substantial excess heat generated during device operation. One possibility to remove the excess heat is to employ substrates with high thermal conductivity. In this contribution we present the growth of GaAs layers by MOVPE on aluminum (111) pseudo-substrates designed for an improved heat management in GaAs electronic circuits. Pseudo-substrates for GaAs deposition were prepared by Al evaporation on (100) GaAs substrate and subsequently heat treated. The GaAs layers exhibit polycrystalline character with high preferential orientation in (100) direction. The roughness of the layers was in the range of 10 to 100 nm and the thickness in the range of 500 - 3000 nm. These layers exhibit extremely low carrier lifetime due to the growth-induced defects and are suitable for fabrication of ultrafast MSM photodetectors.