M-center in 4H-SiC: Isothermal DLTS and first principles modeling studies

Abstract

We report on a bistable defect known as M-center, here introduced in n-type 4H-SiC by 2 MeV He ion implantation. Deep levels of the M-center are investigated by means of junction spectroscopy techniques, namely, deep level transient spectroscopy (DLTS) and isothermal DLTS. In addition to previously reported three deep levels arising from the M-center (labeled as M1, M2, and M3), we provide direct evidence on the existence of a fourth transition (labeled as M4) with an activation energy of 0.86 eV. Activation energies and apparent capture cross sections for all four metastable defects are determined. From first-principles calculations, it is shown that the observed features of the M-center, including the charge state character, transition levels, bi-stability dynamics, and annealing, are all accounted for by a carbon self-interstitial.