Semiconductor structure and manufacturing method thereof

The embodiment of the invention provides a semiconductor structure and a manufacturing method thereof. The method comprises: providing a silicon substrate, epitaxially forming a germanium film on thesilicon substrate, and epitaxially growing a gallium arsenide film on the germanium film, so that the germanium film is used as a buffer layer between the silicon substrate and the gallium arsenide film layer, improve lattice mismatch between the silicon substrate and the gallium arsenide film layer, reduce a reverse domain in the gallium arsenide film layer, reduce defects in the gallium arsenidefilm layer and improve the performance of a device based on the gallium arsenide film layer. 本申请实施例提供了一种半导体结构及其制造方法，包括提供硅衬底，在硅衬底上外延形成锗膜，在锗膜上外延生长砷化镓膜，这样将锗膜作为硅衬底和砷化镓膜层之间的缓冲层，改善硅衬底和砷化镓膜层之间的晶格失配，减少砷化镓膜层中的反向畴，减少砷化镓膜层中的缺陷，提高基于砷化镓膜层的器件的性能。