Temperature dependence of interdiffusion-induced III–V compound formation at the interface between Al, Ga, In layers and Sb substrates

The reactivity and diffusion of atoms at III–V interfaces is studied from group-III overlayers on group-V substrates. The interfaces are formed by an MBE-like deposition of Al, Ga, and In on UHV-cleaved Sb(111) substrates at temperatures sufficiently low to suppress the III–V formation, followed by a continuous temperature ramp. A systematic investigation of the temperature dependence of the formation of III–V compounds during the temperature ramp is presented. It allows insight into the diffusion barriers involved. The process is monitored by Raman spectroscopy as the main tool. Besides, the initial and final state is characterized by AES and LEED. The threshold temperature observed increases with the group-III species from InSb (−15°C) over GaSb (40°C) to AlSb (165°C). A layer-like reactive growth is found for InSb, while AlSb and GaSb tend to island formation.