Deep level capture barrier in molecular beam epitaxial grown AlAsySb1−y measured by isothermal capacitance transient spectroscopy

Abstract

Improved isothermal capacitance transient spectroscopy (ICTS), which measures the entire capacitance transient as a function of time and temperature in a single temperature scan, has been implemented in a deep level trap analysis extending the characterization to include capture barrier measurement. This method eliminates inaccuracies introduced by narrow pulse widths that are difficult to reproduce accurately, providing capture barrier information more accurately and easily in addition to the usual deep level characteristics. A method of establishing ICTS experimental conditions and a method of analyzing the resulting data are described and applied to the investigation of deep levels in Te-doped AlAs0.07Sb0.93. The sample shows a single DX center trap having a deep level energy of 278 meV, a high temperature capture cross section of 1.3×10−12 cm2, and a capture barrier energy of 137 meV, clearly demonstrating the superior method of measuring a capture barrier.