Growth of high-quality GaAs epitaxial layers on Si substrite by using a novel GeSi buffer strucuture

Abstract

A technique to grow high-quality GaAs layers on Si(100) substrate by using a novel SiGe buffer structure is proposed. For the growth of this SiGe buffer structure, a 0.8mum Si0.1Ge0.9,g layer was first grown. Due to the large mismatch between this layer and the Si substrate, many dislocations formed near the interface and in the low part of the Si0.1Ge0.(9) layer. A 0.8mum Si0.05Ge0.95 layer and a 1.0mum top Ge layer were subsequently grown. The Si0.05Ge0.95/Si0.1Ge0.9 and Ge/Si0.05Ge0.95 interfaces formed can bend and terminate the upward-propagated dislocations very effectively. The in situ annealing process is also performed for each individual layer after growth. Finally a 1-3mum GaAs film was grown by MOCVD at 650square. The experimental results show that the dislocation density in the top Ge and GaAs layers can be greatly reduced, and the surface was kept very smooth after growth, while the total thickness of the structure was kept relative thin after the growth (square3.0mum SiGe buffer struture+3.0mum GaAs layer).