BISTABILITY OF CHARGE ACCUMULATED IN LOW-TEMPERATURE-GROWN GAAS

Capacitance-voltage characteristics were studied at various temperatur es for Schottky barriers formed on n-GaAs/low-temperature-grown (LT)-G aAs/n-GaAs sandwich structures. Charge accumulation at deep traps in t he LT-GaAs layer was observed. At room temperature, the C-V characteri stics were found to be step-like with a wide plateau originated from e mission of electrons accumulated in the LT-GaAs layer. At the temperat ure below 100 K, the electron emission from the LT-GaAs layer was comp letely suppressed. At intermediate temperatures (150-200 K), an effect of charge bistability was observed, which manifested itself as a hyst eresis in the capacitance under sweeping the reverse dc bias. We suppo se that the phenomenon takes place when the sweeping rate is higher th an the electron emission rate but lower than the electron capture rate by the deep traps in the LT-GaAs layer. (C) 1998 American Institute o f Physics. [S0003-6951(98)03345-2].