关键词: diamond, silicon vacancy, doping mechanism, unintentional doping

Abstract: Diamond with silicon vacancies has an important role as a promising single-photon source applicable in the quantum information field. However, in a microwave plasma chemical vapor deposition (MPCVD) system, due to the presence of unintentional silicon doping sources such as quartz windows, the behavior of silicon vacancy formation in silicon-doped diamond is complex. In this work, the underlying mechanism of formation of silicon vacancies by unintentional silicon doping in diamond is investigated from the perspective of growing surface kinetics in a two-gas-flow MPCVD system. This system is equipped with a novel susceptor geometry designed to deliver an additional gas flow directly onto the substrate surface. Increasing the concentration of growth doping substances on the substrate surface thereby enhances the efficiency of silicon vacancy formation in diamond. At the same time, by changing the substrate deposition angle the distribution of gas and plasma on the substrate surface is changed, thereby regulating the concentration and distribution of silicon vacancies formed by unintentional silicon doping. Experimental and computational results demonstrate that the difference in silicon vacancies formed by unintentional silicon doping in diamond depends on the substances present on the substrate surface and the distribution of plasma.

Key words: diamond, silicon vacancy, doping mechanism, unintentional doping