Overview of the irradiation-dependent behaviour of the negative dielectric properties of GaAs-based MIS devices

Abstract

In this study, negative dielectric properties of the natural oxide interfacial-layered metal-insulator-semiconductor (MIS) type structure have been investigated under different radiation doses. Some essential parameters of the GaAs-based MIS structure, such as dielectric constant (ε′), dielectric loss (ε'') and loss factor (tanδ), were obtained from the capacitance/conductance-voltage (C-G/ω-V) data for before and after radiation to investigate the effects of gamma-rays on the dielectric properties of the device. Measurements were performed in the voltage range of ±4 V, 500 kHz frequency and at room temperature for before irradiation and after 5 and 10 kGy radiation doses to obtain C-G/ω-V data under various conditions. On the other hand, the voltage-dependent variation of the ac-conductivity (σac) and complex electric modulus (M*) (including its real (M′) and the imaginary (M″) parts) of the structure were calculated before and after radiation. As a result, the peaks at approximately 1.75 V were observed in the voltage-dependent variation of the dielectric constant before irradiation and after all radiation doses. It was also observed from this point that the dielectric constant quickly took negative values, and these behaviours were attributed to the structure's differential change of charge, polarization, and electrical resonance. However, there was no significant change in the radiation-dependent dielectric properties of the structure up to the abnormal peak values. In conclusion, it can be said that although the device is generally resistant to ionizing radiation, it exhibits significant change behaviour in the negative dielectric region. This result means that when the device is operated under appropriate conditions, it can respond as a radiation-resistant rectifier diode or electronic device that can benefit from its negative dielectric properties.