Conditions of growth of high-quality relaxed Si1–xGex layers with a high Ge content by the vapor-phase decomposition of monogermane on a sublimating Si hot wire

Abstract

The conditions of the epitaxial growth of high-quality relaxed Si_1–xGe_x layers by the combined method of the sublimation molecular-beam epitaxy and vapor-phase decomposition of monogermane on a hot wire are considered. The combined growth procedure proposed provides a means for growing Si_1–xGe_x layers with a thickness of up to 2 µm and larger. At reduced growth temperatures (T_S = 325–350°C), the procedure allows the growth of Si_1–xGe_x layers with a small surface roughness (rms ≈ 2 nm) and a low density of threading dislocations. The photoluminescence intensity of Si_1–xGe_x:Er layers is significantly (more than five times) higher than the photoluminescence intensity of layers produced under standard growth conditions (T_S ≈ 500°C) and possess an external quantum efficiency estimated at a level of ~0.4%.