$\alpha$–$\beta$ phase transition in the impurity phase of a SiO$_2$ single crystal

Thermal oxidation of a silicon single crystal in the temperature range of 293–1293 K was studied using high-temperature X-ray diffraction directly on the beam. An anomaly in the intensity and angular position of diffuse scattering from the surface of the single crystal was found. The anomaly is explained by the oxidation of the silicon surface according to the Dill Grove model, including the process of thermal oxidation and sublimation of the oxide layer depending on temperature. It was found that in the bulk of a single crystal (silicon medium) in this temperature range, there is $\alpha$–$\beta$ phase transition in the crystalline phase of silicon dioxide, similar to the $\alpha$–$\beta$ transition of quartz in the atmosphere.