A magnetic resonance spectrum was identified, which was associated with minority carrier lifetime killing defects in device-quality 4H SiC, via magnetic resonance measurements in bipolar junction transistors using spin-dependent recombination. The spin-dependent recombination spectrum had 9 distinguishable lines. It was, within experimental error, essentially isotropic with 4 distinguishable pairs of side-peaks symmetrical about the strong center line. The line shape was, within experimental error, independent of bias voltage and recombination current. The large amplitude and spacing of the inner pair of side-peaks and 3 more widely separated pairs of side peaks were not consistent with either a simple silicon or carbon vacancy or a carbon or silicon antisite. This indicated that the lifetime killing defect was not a simple defect but a defect aggregate. The spectrum was consistent with a multidefect cluster with an electron spin S = ½. The observed spectrum had not been reported previously in the magnetic resonance literature on SiC. A fairly strong argument could be made in terms of a first order model linking the SDR spectrum to a divacancy or possibly a vacancy/antisite pair. The spin-dependent recombination amplitude versus gate voltage was semiquantitatively consistent with a very simple model in which the defect was uniformly distributed within the depletion region of the base/collector junction and was also the dominating recombination center. The large relative amplitude of the spin-dependent recombination response was more nearly consistent with a Kaplan–Solomon–Mott-like model for spin dependent recombination than the Lepine model.

Direct Observation of Lifetime Killing Defects in 4H SiC Epitaxial Layers through Spin Dependent Recombination in Bipolar Junction Transistors. C.J.Cochrane, P.M.Lenahan, A.J.Lelis: Journal of Applied Physics, 2009, 105[6], 064502