The effect of low-field injection of charge carriers on the electrical properties of the metal-oxide-semiconductor structures

The method of high-frequency capacitance-voltage characteristics was used to study the effect of low-field injection of charge carriers on the electrical properties of metal-SiO2-Si structures with n- and p-type substrates. It is shown that in all cases of injection (irrespective of the polarity of the voltage at the gate), an effective positive charge is generated in the oxide; after completion of the injection, this charge relaxes with characteristic times that depend on the bias voltage applied to the gate and the type of the metal-oxide-semiconductor structure. In the structures with p-Si substrates, in the case of a positive voltage applied to the gate, a capacitance minimum appeared in the inversion portion of the capacitance-voltage characteristics in the course of injection; this effect became more pronounced as the gate voltage was increased. After the injection, the capacitance gradually approached the initial value (before injection).