Evaluation of the border traps in LPCVD Si3N4/GaN/AlGaN/GaN MIS structure with long time constant using quasi-static capacitance voltage method

Abstract

We extract the electric properties of border traps with long time constant in low-pressure chemical vapor deposition (LPCVD) Si3N4/GaN/AlGaN/GaN metal–insulator–semiconductor (MIS) structure using quasi-static capacitance voltage method. The energy and depth distribution of the border traps is calculated based on the analysis of energy band diagram and charging dynamic of border traps in the MIS structures. With this method, it is found that LPCVD Si3N4/GaN/AlGaN/GaN MIS structure have a high density of border traps in the order up to 1021 cm−3 eV−1 located at energy level between E C,GaN − 0.04 eV and E C,GaN − 0.66 eV with distance of 1.0–4.2 nm from the Si3N4/GaN interface. Microstructure analysis suggests that the high density of border traps is possibly correlated to the oxygen content at the Si3N4/GaN interface. Meanwhile, the proposed method is also suitable for MIS or metal-oxide-semiconductor structure on other semiconductors, providing another powerful tool to analysis the physical properties of border traps.