Keywords: silicon gallium arsenide, germanium surface, MOCVD, defect density, roughness
Silicon devices and III-V devices are the two camps of semiconductor devices. In order to achieve the complementarity between the two materials and device systems and to obtain better comprehensive performance, silicon-based III-V devices have become a focus of industry and scientific research. .
In this paper, a high-quality, flat surface Si-based GaAs layer is realized by a Ge transition layer, a low-temperature GaAs buffer layer, and a GaAs surface treatment.
The atomic arrangement of the Si-based Ge surface under different conditions was studied by LEED. It was verified that the surface of the chamfering Ge/Si was Ge(1119)-(1×2) reconstructed surface. For the stepped tantalum surface, the dimer chemical bond direction is parallel to the stepped form (DB), and the energy is the lowest. Based on the GaAs/Ge epitaxy, a high quality GaAs/Ge/Si system is obtained. The half width of the HRXRD of the GaAs top layer is narrower (40 arcsec), and the defect density of the top GaAs can reach 2.3×105 cm-2. A secondary epitaxial silicon-based gallium arsenide material having a surface roughness of less than 0.6 nm. At the same time, the low-temperature spectral characteristics of GaAs-based, Ge-based, and Ge/Si-based GaAs epitaxial layers are compared. The Ge-based and Ge/Si-based GaAs materials cause photoluminescence peaks to drift and split light and heavy holes due to tensile strain. The strength of the Ge-based and Ge/Si-based GaAs layers is comparable to that of the GaAs homoepitaxial layer, which differs by a few meV from the latter.
The high quality, flat surface GaAs/Si obtained herein is a condition for the preparation of a silicon-based III-V compound semiconductor device.