Large enhancement of interband tunneling current densities of over 10(5) A/cm(2) in In0.53Ga0.47As-based surface tunnel transistors

In0.53Ga0.47As-based Surface Tunnel Transistors (STT's), which control an interband tunneling current between an n-type channel and a p-type drain by an insulated gate, are investigated with the goal of increasing the tunneling current density for high-speed operation. The fabricated devices enhanced an interband tunneling current density by a factor of 10(3) compared to the conventional GaAs-STT's due to a smaller bandgap energy and a lighter electron effective mass, and exhibited a clear gate-controlled negative differential resistance (NDR) characteristics with maximum tunneling current densities of over 10(5) A/cm(2). The cutoff frequency (f(T)) and maximum oscillation frequency (f(max)) of a fabricated device with a 1,0-mu m gate length were estimated to be 7.9 GHz and 20 GHz, respectively, in the NDR region.