Preparation for relaxation thin SiGe virtual substrate

Abstract

The invention discloses a preparing method for relaxed thin SiGe virtual substrates, which comprises steps of preparing a silicon substrate, preparing an incompletely relaxed thin SiGe layer with high Ge content and low surface roughness on the silicon substrate by utilizing low temperature pressure-reduced epitaxy, depositing a silicon dioxide through LPCVD or PECVD in low temperature to cover the thin SiGe layer, performing high-temperature fast-speed thermal annealing to completely relax the thin SiGe layer, and then removing the oxide layer to obtain the relaxed thin SiGe material layer with low surface roughness, high Ge content and high quality. By integrally utilizing the low temperature pressure-reduced epitaxy, the low temperature deposited oxide layer, the fast thermal annealing and the like on the semiconductor silicon substrate, a layer of relaxed thin SiGe virtual substrate with high quality high Ge content and low surface roughness is prepared by the preparing method, and the preparing method can be applied to various channel strain engineering and preparation of high-mobility channel materials in future CMOS process to further increase performance of CMOS devices.

Description

technical field [0001] The invention relates to the technical field of semiconductor materials, in particular to a method for preparing a relaxed thin SiGe dummy substrate. Background technique [0002] In the semiconductor industry, silicon has been developed as the dominant semiconductor material for decades and has shown good performance. However, with the continuous reduction of device feature size, the size of a single transistor gradually reaches the dual limit of physics and technology, and the mobility of CMOS devices using silicon as the channel material is getting lower and lower, which can no longer meet the requirements of continuous improvement of device performance. Therefore, it is necessary to introduce strain engineering to improve the mobility of silicon materials, or directly adopt other materials with relatively high mobility such as germanium (Ge) to replace silicon (Si) as the channel material of the device, and due to the silicon process and equipment ...

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Problems solved by technology

[0005] The problem to be solved by the present invention is to provide a method for preparing a relaxed thin SiGe virtual substrate, so as to overcome the defects of relatively large SiGe layer thickness and relatively large surface roughness in the prior art

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