Obtaining High-Quality Silicon-Based Gallium Arsenide Materials

Keywords: Silicon-based gallium arsenide, germanium surface, MOCVD, defect density, roughness. Silicon devices and III-V semiconductor devices represent the two major camps in the field of semiconductor devices. To achieve complementarity between these two material and device systems and to attain superior overall performance, silicon-based III-V devices have become a key focus in both industry and research. In this paper, we have achieved high-quality, flat Si-based GaAs layers by employing a Ge transition layer, a low-temperature GaAs buffer layer, and GaAs surface treatment. Using LEED, we investigated the atomic arrangement on Si-based Ge surfaces under different conditions, thereby confirming the existence of a tilted-angle Ge surface.

　　Keywords: Silicon-based gallium arsenide, germanium surface, MOCVD, defect density, roughness

　　Silicon devices and III-V devices represent the two major camps in semiconductor technology. To achieve complementarity between these two material and device systems and to attain superior overall performance, silicon-based III-V devices have become a key focus in both industry and research.

　　This paper achieves high-quality, flat-surfaced Si-based GaAs layers by employing a Ge transition layer, a low-temperature GaAs buffer layer, and GaAs surface treatment.

　　Using LEED, we investigated the atomic arrangement on Si-based Ge surfaces under different conditions and confirmed that the Ge/Si surface with a tilted cut exhibits a Ge(1119)-(1×2) reconstructed surface. For this stepped germanium surface, the dimer chemical bonds oriented parallel to the step reconstruction (DB configuration) constitute the majority and have the lowest energy. Based on GaAs/Ge epitaxy, we obtained a high-quality GaAs/Ge/Si heterostructure in which the full width at half maximum (FWHM) of the HRXRD peak for the top-layer GaAs is relatively narrow (40 arcsec), and the defect density in the top-layer GaAs can reach as low as 2.3 × 10⁵ cm⁻². Through surface treatment, we achieved secondary epitaxial GaAs-on-Si materials with a surface roughness below 0.6 nm. This paper also compares the low-temperature spectral properties of GaAs-based, Ge-based, and Ge/Si-based GaAs epitaxial layers. Due to tensile strain, both Ge-based and Ge/Si-based GaAs materials exhibit shifts in their photoluminescence peaks and splitting of the light and heavy hole bands. The intensity of the Ge-based and Ge/Si-based GaAs layers is comparable to that of homogeneously grown GaAs layers, while their FWHM differs from the latter by only a few meV.

　　The high-quality, flat-surfaced GaAs/Si obtained in this study has prepared the conditions for the fabrication of silicon-based III-V compound semiconductor devices.

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