Capacitance behavior of GaAs-MIS structures with low-temperature grown GaAs dielectric

Low temperature (LT-) grown GaAs has been used as a dielectric in a metal/dielectric/semiconductor structure, and its capacitance behavior has been investigated by C-V-B and admittance spectroscopy. The C-V-B measurement revealed a barrier height of 0.40 eV at the interface of the LT- and n-GaAs. The capacitance-temperature profile shows a step decrease in capacitance, accompanied by a maximum conductance as the measurement temperature was decreased. The detailed investigation shows that this anomalous C-T behavior is caused by the increase of resistivity of the LT-GaAs, which leads to the formation of a metal/insulator/semiconductor structure at low temperature. This result has an impact on the application of the LT-GaAs,because it introduces a frequency dispersion to the device characteristics.