Epitaxial 4H-SiC n-type layers implanted at room temperature with a low fluence of mega-electron-volt protons were measured by deep level transient spectroscopy. A proton fluence of 1012/cm2 created an estimated initial concentration of intrinsic point defects of about 1014/cm3 of which about 10% remain after the implantation and gives rise to deep states in the upper part of the band gap. Samples were investigated here prior to high-temperature annealing, and a very complex spectrum was revealed. In particular, a bistable defect M was discovered which exhibited 2 deep level transient spectroscopic peaks, M1 and M3 at Ec–0.42 and around Ec–0.75eV, respectively, in one configuration and one peak, M2 at Ec–0.70eV in the other configuration. The charge dependent thermal activation energies for the transformation between the bistable defect peaks were 0.90 and 1.40eV.

Bistable Defect in Mega-Electron Volt Proton-Implanted 4H Silicon Carbide. D.M.Martin, H.Kortegaard Nielsen, P.Lévêque, A.Hallén, G.Alfieri, B.G.Svensson: Applied Physics Letters, 2004, 84[10], 1704-6