Temperature dependence of current conduction in semi-insulating 4H-SiC epitaxial layer

We have investigated temperature dependence (94 K-650 K) of current conduction in semi-insulating 4H-SiC epitaxial layer. The epitaxial layer was grown on highly doped n-type (0001) 4H-SiC substrate using chemical vapor deposition with dichlorosilane precursor. The current-voltage (I-V) characteristics exhibited steps at similar to 1 V and similar to 70 V that were attributed to the filling of deep level centers by injected electrons. Correlation of the I-V characteristics with the results of thermally stimulated current measurements showed that deep centers peaked at 242 K, 285 K, and 500 K, were responsible for the steps in the I-V characteristics. Slow processes of the injected carrier capture on traps resulted in the I-V characteristic with negative differential resistance. (C) 2012 American Institute of Physics. [doi:10.1063/1.3676270]