Resolving emission rates from overlapping capacitance transients of deep levels in SiC

Abstract

<p> <span>With the development of new materials and devices, defect characterization techniques, such as deep level transient spectroscopy, face the challenge of providing more accurate defect information and identification. However, nonexponential capacitance features are introduced for various reasons, making the widely adopted rate window technique encounter difficulties during analysis, which may lead to incorrect conclusions. In this study, the capacitance transients of a SiC junction barrier Schottky diode were systematically analyzed, revealing an overlap of majority and minority carrier trap emission signals within the same measurement temperature. Additionally, the capacitance transients of electron traps contained two similar emission rates. If the selection of rate window is inappropriate, it not only becomes difficult to distinguish each trap, but also false signals may appear. By comparing the rate window and exponential fitting method, the emission rates, activation energy, and capture cross-section can be calculated separately, and this comparative analysis may help improve reliability. Furthermore, the concentration profiles of each trap as a function of depth are analyzed by applying different voltages, and the possible origins of these traps are discussed.</span> <br></p>