Growth and patterning of GaAs/Ge single crystal layers on Si substrates by molecular beam epitaxy

Abstract

Single crystal GaAs layers have been grown on Si substrates with an intermediate Ge layer. Both the Ge and subsequent GaAs are grown in situ by molecular beam epitaxy (MBE). Cross-sectional transmission electron microscopy studies show GaAs surface dislocation densities on the order of 107 cm−2. The quality of the GaAs is indicated by a mobility within 15% of that measured on GaAs/GaAs MBE structures doped at the same level. This material also exhibits a photoluminescence signal with a room-temperature intensity about 50% of GaAs grown on GaAs, and with a similar half-width. In this letter, electron diffraction, optical and electrical data are presented for n-type GaAs/Ge/Si structures. In addition, a selective lift-off technique is demonstrated, with possible applications in the development of monolithic GaAs/Si integrated circuits.