Current Transport and Capacitance-Voltage Characteristics of GaAs and InP Nanometer-Sized Schottky Contacts Formed by in situ Electrochemical Process

The nanometer-sized Schottky contacts were successively fabricated on n-GaAs and n-InP substrates by the electrochemical process, and their electrical properties were characterized both experimentally and theoretically. From the detailed I-V measurements using a conductive AFM system, it was found that the current transport properties of the nanometer-sized Schottky contacts were strongly dependent on metal workfunction, however showed nonlinear log I-V characteristics with large n value in range of 1.2 - 2.0 which can not be explained by 1D thermionic emission model. From the theoretical analysis using a computer simulation, it was found that this nonlinear characteristics can be explained by the 3D thermionic emission model with a due consideration of the environmental Fermi level pinning. Furthermore, the calculated C-V characteristics showed much smaller movements of the depletion layer with bias underneath the nano-Schottky contacts. These results strongly indicate the importance of controlling the environmental Fermi level pinning to improve the potential controllability of the nano-Schottky contacts.