The effect of gamma irradiation on electronic and interfacial properties of the Al/Congo Red/P-Type Si semiconductor diodes

The investigation of irradiation effects on solid state circuits and materials has attracted as many scientists and space agencies of the different countries are worked in the relevant topic. If the photon or particles radiation applies to the solid state circuits and materials, they will experience hard degradation. The permanent or transient degradation on the semiconductor devices may occur in this irradiation procedure. In this thesis, the p- type silicon semiconductor substrates were used for fabrication of MIS diode. After chemical cleaning procedure, Al/Congo Red (CR)/p-Si MIS diode structure was produced by metalization of ohmic back contact and Al top contact. Organic CR thin film on the Si wafers was made from covering of the congo red dye solution (0.2% in ethanol). To investigate the irradiation effect on the Al/CR/p-Si MIS contact, Current–Voltage (IV) and Capacitance-Voltage (CV) measurements were performed after and before Co-60 γ- irradiation. The ideality factor (n), the barrier height (Φb) and series resistance (Rs) from the I-V data were obtained from traditional LnI-V characteristics, Cheung functions and Norde function. Interface state density (Nss) of the Al/CR/p-Si MIS contact was also calculated. The diffussion potential (Vd), the barrier height (Φb) and acceptor charge concentration (Na) from the C-V data of the device were calculated.