The behavior of medium-deep electron traps (EL5, EL6, etc) in n-type bulk crystals was monitored by means of isothermal constant capacitance-voltage transient spectroscopy. Each such spectrum of EL5 and EL6 was broader than the theoretical one which was expected for a single level, and was found to consist of more than 2 trap components. An anomalous filling-time dependence of the capacitance-voltage transient spectroscopic peak heights for these traps was observed when the filling pulse width was varied over a wide range. Thus, one component of EL6 decreased to about 50% of its maximum value, while one component of EL5 increased and saturated. The decrement of the constituent of EL6 was nearly equal to the increment in that of EL5. These variations could be reversed by controlling the electron occupation fractions of these traps by changing the time interval between 2 adjacent filling pulses upon applying the isothermal double-pulse constant capacitance-voltage transient spectroscopic method. Such an interaction was commonly observed in n-type bulk GaAs, regardless of the carrier concentration and growth method. The behavior of the medium-deep electron traps could be explained by analogy with an electronically controlled bistable reaction.

Bistable behavior of a medium-deep center related to EL5 and EL6 in n-type bulk GaAs H.Shiraki, Y.Tokuda, K.Sassa: Journal of Applied Physics, 1998, 84[6], 3167-74