SCHOTTKY-BARRIER CONTACTS ON (P)-GA0.47IN0.53AS

Schottky diodes were prepared by evaporation of six different metals (Ag, Al, Ti, Au, Ni and Pt) onto p-type Ga0.47In0.53As with a chemically etched surface. The barrier heights φB were measured using I-V, I-T and C-V techniques. The values of φB were between 0.47 and 0.73 eV, depending on the metal and measurement technique used. Non-ideal I-V characteristics were observed. Forward current (at 150 mV bias) activation energies of about 0.4 eV at room temperature and 0.3 eV at a low temperature were determined. The Richardson constant, *Am, was found to be 3-4 times less than the predicted one given as A(m*/m0). Temperature dependences of φC-VB exhibited two regions with temperature coefficients of about 1.4 × 10-3 eV/K and 2.5 × 10-4 eV/K at room and low temperatures, respectively. Interfacial layers of different origins and properties are supposed to be present. The total Schottky barriers probably consist of two barriers which are determined either by Fermi level pinning or by As segregation at the interface. Annealing temperature higher than 380°C destroys the Schottky barrier. © 1990.