Study of proton irradiation-induced effects on electrical and optical characteristics of AlGaN/GaN epi-structures

Due to their crystal structure and inherent properties of AlGaN and GaN, the AlGaN/GaN high electron mobility transistors (HEMTs) are the highly promising candidates for electronic applications in the harsh conditions such as high voltage, high frequency, high power and the hostile radiation environments in the space. It is necessary to have a clear understanding of the radiation effects on the materials/devices and investigate the failure mechanisms before the successful deployment of their applications. In the present research, the effects of 100 keV proton irradiation at 1E10, 1E12 and 1E14 fluences on AlGaN/GaN epi-structures grown on Si wafers were studied. The degradation of electrical characteristics and shift in the threshold voltage was observed from the irradiated samples. The optical properties of the material were analyzed by Raman and PL spectroscopy. The change in the surface morphology of the samples after irradiation was confirmed by atomic force and scanning electron microscopic analyses. The compositional analysis was performed using X-ray photoelectron spectroscopy. Electrical characteristics of the device were analyzed using conventional transistor I-V measurements. Details of the experimental methods and the analysis of the results will be presented.