Electrical characterization of deep levels created by bombarding nitrogen-doped 4HSiC with alpha-particle irradiation

摘要

Deep-level transient spectroscopy (DLTS) and Laplace-DLTS were used to investigate theeffect of alpha-particle irradiation on the electrical properties of nitrogen-doped 4H-SiC. Thesamples were bombarded with alpha-particles at room temperature (300 K) using anamericium-241 (241Am) radionuclide source. DLTS revealed the presence of four deep levelsin the as-grown samples, E0.09, E0.11, E0.16 and E0.65. After irradiation with a fluence of 4.1 ×1010 alpha-particles-cm–2, DLTS measurements indicated the presence of two new deeplevels, E0.39 and E0.62 with energy level, EC – 0.39 eV and EC –0.62 eV, with an apparentcapture cross sections of 2×10–16 and 2×10–14 cm2, respectively. Furthermore, irradiation withfluence of 8.9×1010 alpha-particles-cm–2 resulted in disappearance of shallow defects due to alowering of the Fermi level. These defects -minutes. Defects, E0.39 and E0.42 with close emission rates were attributed to silicon or carbonvacancy and could only be separated by using high resolution Laplace-DLTS. The DLTSpeaks at EC – (0.55-0.70) eV (known as Z1/Z2) were attributed to an isolated carbon vacancy(VC).