MBE REGROWTH WITH HYDROGEN CLEANING AND ITS APPLICATION FOR THE FABRICATION OF SURFACE TUNNEL TRANSISTORS

Regrown interfaces of GaAs and GaSb, which were prepared by hydrogen cleaning prior to molecular-beam epitaxy (MBE) regrowth, were characterized. Among various hydrogen cleaning methods explored in this study, the absence of carrier depletion around the interface was reproducibly obtained by cleaning with either hydrogen gas or its radicals. For p-A]GaSb/GaSb modulation-doped structures in which p-AlGaSb layers were regrown, proper accumulation of a two-dimensional hole gas at the interface was confirmed when cleaned with hydrogen radicals. This MBE-regrowth technique was then utilized to fabricate new transport devices, surface tunnel transistors (STTs), for which the quality of the regrown interface severely limits device operation. The STTs thus fabricated exhibited proper transistor characteristics.