TEMPERATURE-DEPENDENCE OF THE ELECTRICAL CHARACTERISTICS OF AG IN0.53GA0.47 AS DIODES FORMED AT LOW-TEMPERATURE/

Schottky contacts on n-In0.53Ga0.47As have been made by metal depositi on on substrates cooled to a temperature of 77 K. The current-voltage and capacitance-voltage characteristics showed that the Schottky diode s formed at low temperature had a much improved barrier height compare d to those formed at room temperature. The Schottky barrier height, ph i(B), was found to be increased from approximately 0.2 to 0.60 eV with Ag metal. For the low temperature diode, the saturation current densi ty, J0, was about 4 orders smaller than for the room temperature diode . A transport mechanism dominated by thermionic emission over the barr ier for the LT diode was found from current-voltage-temperature measur ement. Thermionic field emission is seen for the higher doped substrat e with reverse bias. Deep level transient spectroscopy studies of n-In GaAs low temperature diodes exhibited a bulk electron trap at E(c) - 0 .23 eV. The low temperature process appears to reduce metal induced su rface damage and may form an MIS-like structure at the interface.