Evidence for bistable defects in 6H-SiC

A thermodynamic description of the Pd–Si–C system

“…Meanwhile, the formation and the properties of metal/SiC interfaces are of great importance and also in high temperature applications in metal/ceramic composites. Several contact properties of Pd on single crystals of SiC have been reported by Chaudry et al [2], Staiko et al [3] and Waldrop [4], respectively. Another area of interest for the Pd-Si-C system is in the metallurgy of nuclear fuel in high temperature gas cooling reactor [5].…”

Kinetics of slow buildup of photoconductance in n-type 6H–SiC

“…Attempts to fit the data with only one term of Eq. ͑1͒ as suggested by Lacklison et al 15 and as was carried out for AlGaAs 16 and more recently by Staikov et al 8 for SiC were unsatisfactory. The solid lines are fits to the data using Eq.…”

“…2 that G p (t) increase with temperature. Staikov et al 8 reported an increase in photogenerated free electrons with an increase in temperature in 6H-SiC. They, however, attributed this to the existence of a metastable state that traps the photogenerated carriers at low temperatures but not at high temperatures.…”

“…7 Such a metastable defect to explain the PPC effect in SiC has not been clearly identified. Based upon Hall effect measurements, Staikov et al 8 reported that the free-electron concentration, n, of a sample in PPC mode, shows a slow transient with a long characteristic time constant. The electron concentration in a sample exhibiting conventional photoconductivity ͑PC͒ reaches its saturation value rapidly when the sample is exposed to light.…”

“…For example, recently, it was reported that n-type 6H-SiC exhibits a persistent photoconductivity ͑PPC͒ effect at low temperatures. 5,6 The PPC effect usually indicates the existence of a barrier that prevents the recapture of photogenerated carriers thus prolonging the photoconductivity effect long after the excitation has been terminated. This is the case in Si ͑or Te͒ doped AlGaAs, where the barrier prevents the recapture of photoexcited electrons by the DX center ground state.…”