CBE SELECTIVE EMBEDDED GROWTH FOR QUASI-PLANAR GAAS HBT APPLICATION

This paper describes a new HBT epitaxial process using CBE selective embedded growth of GaAs and related materials, in order to obtain quasi-planar self-aligned HBTs. A perfect growth selectivity is first defined above a critical substrate temperature of 640 and 550-degrees-C, respectively, for GaAs and In containing compounds such as Ga1-xInxAs and Ga0.51In0.49P. Selective embedded GaAs growth is found to fill quite well a hole of a few mum2 area and 1 mum depth without overgrowth. Finally, the surface preparation prior to the regrowth is optimized in order to ensure a low contact resistivity for an n+ regrown HBT collector contact and a functional device.