Impact of Nonhomoepitaxial Defects in Depleted Diamond MOS Capacitors

In this paper, we introduce a set of experiments and analyses to comprehensively correlate the epitaxial structural defects and electrical characteristics in the pseudovertical homoepitaxial boron-doped oxygen-terminated (001) diamond metal-oxide-semiconductor capacitors (MOSCAPs). Current-voltage I(V), capacitance-voltage C(V), and capacitance-frequency C(f) characteristics of the MOSCAPs have been measured and analyzed, with the special focus when the structure is under positive bias, i.e., depletion regime. The defective spots, which are electrically active, have been identified as the origin of the MOSCAP's leakage current in depletion regime. The electrical features of these killer defects are characterized thanks to micrometer scale electrical measurements equipped under scanning electron microscope. The structural features of these killer defects are explored by transmission electron microscopy. By taking into account, the electrical characteristics of the killer defects, we introduced and simulated a small signal equivalent circuit of the whole structure. The comparison between simulations with ac measurements confirms that the gate leakage current appearing in depletion regime induces an inversionlike artifact observed on diamond MOSCAPs C(f, V).