Comprehensive electrical analysis of interface states in Al 2 O 3 /OH-terminated (111) diamond MOSCap
Résumé
Diamond, with its exceptional electrical and thermal characteristics, is a promising wide bandgap material for high-performance electronics in extreme environments. However, the efficiency of diamond-based metal oxide semiconductor devices is often hindered by interface states between the diamond and the oxide layer, which can degrade mobility, threshold voltage, and gate control. AlO is commonly used as the insulating layer due to its compatibility with diamond, but its interface with diamond can introduce undesirable states that affect device performance. This work focuses on the OH-terminated (111) diamond/AlO interface, which has shown potential for normally-off metal oxide semiconductor field effect transistor with limited interface state density. The paper details the fabrication of OH-terminated (111) diamond/AlO metal oxide semiconductor capacitors, describes an original method combining transfer length measurements with capacitance–voltage and frequency analysis, and discusses the extraction of interface trap density () and their energy distribution. The energy distribution of was estimated using the conductance method, indicating that was in the range of (0.7–0.9) within 0.34–0.49 eV from of diamond. Lastly the electron affinity was estimated to be , the first experimental value for the electron affinity of OH terminated (111) oriented diamond. The results are compared with existing literature to provide insights into the optimization of diamond-based metal oxide semiconductor devices.