Physical and Magnetic Properties of Silicon Doped with Impurity Germanium Atoms

Abstract

This paper presents the results of a study of silicon diffusion-doped with germanium impurity atoms. For the diffusion of germanium impurity atoms, the original single-crystal silicon of the KEF-100 brand was used, in which the phosphorus concentration was equal to Np≈5ꞏ10¹³cm^-3. The selection of such a concentration of phosphorus impurity atoms was justified by the fact that this concentration of phosphorus atoms has practically no effect on the electrophysical properties of the obtained samples of silicon doped with germanium impurity atoms (Si<Ge>) due to the high solubility of germanium impurity atoms in silicon. As shown by the conducted experimental studies in silicon samples doped by the developed new technology, there are a number of important practical features as well as, the time of the diffusion process of impurity atoms of germanium in silicon according to the developed new technology is reduced by 2‑2.5 times, the power consumption during diffusion is reduced by 2 times, the formation of various impurities, silicides, both on the surface and at the surface region of silicon and surface erosion are almost completely eliminated. The study of the electrophysical and magnetic properties of silicon doped with impurity atoms of germanium showed that on the surface and in the near-surface, in addition to the formation of saturated layers of impurity atoms of germanium, binary compounds Ge_xSi_1-x are also formed. Based on the X-ray energy dispersive microanalysis, it was determined that the concentration of silicon atoms on the surface is ~44.32%, germanium atoms ~38.11%, oxygen atoms ~15.58% and carbon atoms ~1.98%. These data showed that the number of germanium atoms on the surface is almost half the number of the main silicon atoms. The presence of impurity germanium atoms leads to a strong change in the fundamental parameters of the original silicon. The results of the study showed that in the samples of silicon doped with impurity germanium atoms, ferromagnetic properties are observed at relatively high temperatures (T = 300 K). For the first time in the samples of silicon doped with impurity germanium atoms, galvanomagnetic parameters such as M_s-saturation magnetization, M_r-residual magnetization and H_c-coercive force were determined. It was shown that in samples of silicon doped with impurity atoms of germanium, the fundamental parameters (the value of the width of the forbidden zone, mobility and band structure) of the original silicon change in a wide range, which leads to an expansion of the spectral range of photosensitivity, as well as magnetic properties, i.e. ferromagnetism is observed at relatively high temperatures (T=300 K).