Abstract
A current deep-level transient spectroscopy (DLTS) system capable of recording an entire set of current transients was developed and used for characterization of deep levels in n-type 6H-SiC wafers grown in the [1\(\bar 1\)00] direction. The current transients were acquired in the time interval from 10−4 sec to 10 sec and temperature range from 100 K to 700 K. The current transients exhibited nonexponential behavior, which was related to closely spaced traps in the band gap. The logarithmic plot of the current transient was close to linear at most temperatures. Because the conventional approach based on exponential emission of electrons from discrete levels cannot describe the observed nonexponential behavior of current transients, the transients were fitted assuming continuous distribution of traps in the band gap. Theoretically calculated current transients assuming Gaussian distribution of trap centers in the band gap agree with the experimental data fairly well. The results of electrical measurements and theoretical fitting were explained based on a high density of defects in the investigated wafer that were revealed by chemical etching and related to stacking faults.
Published Version
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