1978 年 47 巻 12 号 p. 1133-1139
The behavior of mobile Na+ ions in thermally grown SiO2 film is investigated by using thermally stimulated currents (TSC), thermally stimulated surface potentials (TSSP) and capacitance-voltage (C-V) characteristics. The samples used in the experiments are Al-SiO2-Si, MIS diodes. Results obtained by above three methods cannot be interpreted sufficiently by ionic space charge polarization due to Na+ ions, After bias-temperature (B-T) stress, the shift of the flat-band voltage does not correspond to the depolarization charge in TSC. Further, TSSP is not observed in the temperature region of one of the TSC peaks. These phenomena are considered to be caused by neutralization and ionization of some part of the mobile ions at the insulator-semiconductor (or metal) interface by B-T stress. Estimations of parameters related to the ionic space charge are discussed in the case that charge exchange occurs at the insulator-semiconductor (or metal) interface.