DLTS characterisation of 107 MeV krypton ion-irradiated nitrogen-doped 4H-silicon carbide

Abstract

Swift heavy ions, such as krypton ions, play a significant role in developing and enhancing the performance of various devices. In this study, the influence of Kr2+ on nitrogen-doped 4H-silicon carbide has been investigated using deep level transient spectroscopy (DLTS). Krypton ions, with an energy of 107 MeV, were used to irradiate the Au/Ni/4H-SiC Schottky barrier diodes (SBDs) at a fluence of 1 × 1010 cm–2 at room temperature (300 K). Before the irradiation of the samples, the electrical measurements revealed good rectifying behaviour. However, rectification properties of the Au/Ni/4H-SiC SBDs were completely lost after irradiation at a fluence of 1 × 1010 cm–2. Annealing was performed at 300 °C in flowing argon, and the current–voltage (I–V) and capacitance–voltage (C–V) revealed partial rectification. DLTS of the as-grown devices analyses revealed the presence of four deep level defects. After annealing the irradiated device, the DLTS spectra showed a reduction in the intensity of the E0.10 and the disappearance of the E0.12 as well as the E0.16 defects compared to that as-grown. Two defects with energies of 280 and 410 meV showed inverted peaks, as would have been expected from minority carriers trap instead of majority carriers, which led to confusion as the peaks were inverted. It was concluded that the peculiar characteristics of DLTS measurements on SBDs may be due to the extremely high value of the series resistance as well as the low capacitance. The results of this study provide insight into the behaviour of SBDs under extreme irradiation and can be used to improve the radiation tolerance of electronic devices made from SiC.