Impact of the oxidation temperature on the density of single-photon sources formed at SiO₂/SiC interface

Abstract

The impact of oxidation temperature on the formation of single photon-emitting defects located at the silicon dioxide (SiO₂)/silicon carbide (SiC) interface was investigated. Thermal oxidation was performed in the temperature range between 900 and 1300 °C. After oxidation, two different cooling processes—cooling down in N₂ or O₂ ambient—were adopted. Single photon emission was confirmed with second-order correlation function measurements. For the samples cooled in an N₂ ambient, the density of interface single photon sources (SPSs) increased with decreasing oxidation temperature with a density that could be controlled over the 10⁵ to 10⁸ cm⁻² range. For the O₂ cooled samples, on the other hand, many interface SPSs were formed irrespective of the oxidation temperature. This is attributed to the low-temperature oxidation during the cooling process after oxidation.