Defect investigation of undoped wide bandgap materials: Comparison between charge transient spectroscopy (QTS) and inverse Laplace QTS

Understanding the electrically active defects and impurities in semiconductors, especially in intrinsic or unintentionally doped wide bandgap materials, still remains a challenge. Here, time-of-flight (ToF) measurement using a solid state light source (355 and 213 nm) was performed on intrinsic silicon carbide and single-crystalline diamond. The charge transient spectroscopy (QTS) and the inverse Laplace (IL) QTS methods were applied to analyze the ToF results. Using these methods, we were able to trace the existing impurities in both materials. However, ILQTS proved to be more sensitive, with higher resolution for detection of existing multiple defects. The results suggest that this system can successfully be employed to investigate electrically active impurities at different energy states in highly resistive and undoped materials.