Defect energy levels in electron-irradiated and deuterium-implanted (formula presented) silicon carbide

Abstract

Using deep-level transient spectroscopy, we studied defect energy levels and their annealing behavior in nitrogen-doped (Formula presented) epitaxial layers irradiated with 2-MeV electrons and implanted with 300-KeV deuterium or hydrogen at room temperature. Five levels located at (Formula presented) (Formula presented) (Formula presented) (Formula presented) and (Formula presented) consistently appear in various samples grown by chemical vapor deposition, showing they are characteristic defects in n-type (Formula presented) epitaxial layers. It is suggested that the (Formula presented) level originates from a carbon vacancy, and that the two levels at (Formula presented) and (Formula presented) which likely arise from the occupation of inequivalent lattice sites, and the level at (Formula presented) are different charge states of the carbon vacancy. The annealing kinetics of the (Formula presented) level are first order with an activation energy of 1.45 eV, and a level at (Formula presented) growing upon its decay arises most likely from a vacancy-impurity complex. The results for the (Formula presented) and (Formula presented) levels are consistent with a defect model involving a silicon vacancy on inequivalent sites in the (Formula presented) lattice. Furthermore, the present results show that at hydrogen doses of (Formula presented) no interaction between hydrogen and the irradiation-induced silicon vacancy takes place even after annealing at temperatures up to 800 °C, in contrast to the results reported for n-type silicon. © 1999 The American Physical Society.