The Effects Of Gamma Radıatıon On The Electrıcal And Dıelectrıc Parameters Of Mıs Structure Wıth Sılıcon Nıtrate Interfacıal Insulator Layer


Thesis Type: Doctorate

Institution Of The Thesis: Gazi Üniversitesi, Fen Bilimleri Enstitüsü, Turkey

Approval Date: 2016

Student: RAZİYE ERTUĞRUL UYAR

Supervisor: ADEM TATAROĞLU

Abstract:

In this study, the effects of gamma radiation on the electrical and dielectric parameters of metal-insulator-semiconductor (MIS) structure with Si3N4 thin film prepared by RF magnetron sputtering method were investigated. The Au/Si3N4/n-Si/Au (MIS) structure was irradiated using gamma-radiation source at a dose rate of 0,69 kGy/h. The capacitance-voltage (C-V) and conductance-voltage (G/ω-V) measurements were carried out at a total dose range of 0-100 kGy for five different frequencies (1, 10, 100, 500 and 1000 kHz). The electrical and dielectric parameters were determined from these measurements before and after irradiation. The value C and G/ω decreases with the increasing radiation dose due to the irradiation-induced defects. Also, the value of C and G/ω decreases with the increasing frequency. The frequency dependence of C and G/ω indicates the existence of interface states at metal-semiconductor interface. The calculated value of series resistance (Rs) increases while the interface states (Nss) value decreases with the increasing radiation dose. This decrease in Nss is due to the reduction in the number of recombination centers at insulator/semiconductor interface. The calculated value of the dielectric constant (ε') and dielectric loss (ε'') decreases with the increase of radiation dose and frequency. While the value of ac conductivity (ac) decreases with the increasing radiation dose, it increases with the increasing frequency. The obtained results showed that the electrical and dielectric parameters of the MIS structure considerably depend on both frequency and radiation.