Investigation of the Effect of X-ray Irradiation on the Contact Parameters of a Barrier Diode via Electrical Characterization

In this study, the effects of high-energy X-ray irradiation on the electrical characteristics of Au/LiF/p-Si/Al barrier diodes were investigated. The device structure was obtained by inserting a thin lithium fluoride (LiF) interfacial layer between gold (Au) and p-type silicon (p-Si) using the thermal evaporation method. The current–voltage (I–V) characteristics of the fabricated diodes were measured under dark conditions at room temperature (300 K). The samples were exposed to X-ray radiation doses of 0 Gy (before irradiation), 25, 50, and 75 Gy, and the variations in the main diode parameters, namely the ideality factor (n), barrier height (Φb), and series resistance (Rs), were analyzed. The electrical parameters were calculated using the thermionic emission (TE) theory, and a detailed analysis was also performed using the Cheung and Norde methods. For the Au/LiF/p-Si/Al device, the ideality factor and barrier height using TE were calculated as 1.22 and 0.64 eV, respectively, before irradiation. At 25 Gy, the ideality factor and barrier height of the device were found to be 1.29 and 0.68 eV, respectively, while at 75 Gy, these values changed to 1.76 and 0.82 eV, respectively. Similar behavior has been observed in calculations using other methods. The obtained results indicated that irradiation significantly affects the diode behavior. Deviations from ideal behavior were observed with increasing radiation dose, which were attributed to radiation-induced defects and interface states.