Determination of parameters of deep level defects from numerical fit of deep level transient spectroscopy spectra: Analysis of accuracy and sensitivity to noise

Abstract

The numerical fit of deep level transient spectroscopy (DLTS) spectra, used primarily to analyze complex DLTS spectra, is evaluated in terms of the accuracy of measuring deep levels and the sensitivity to noise. It is shown that by using numerical fit of DLTS spectra, the uncertainties in the emission activation energy and the capture cross section of deep level defects can be improved by three to four times over the standard Arrhenius plot method. Two modifications of the fitting procedure are tested: a fit of a DLTS spectrum using one rate window, and a simultaneous fit using five different rate windows. It is shown that simultaneous fit of spectra using different rate windows is significantly more accurate, has noticeably larger convergence radius for the initial values of parameters, and is less sensitive to noise. The advantages of the fitting routine are demonstrated on experimentally obtained noisy DLTS spectra.