Polycrystalline Ge intermediate layer for Ge/Si wafer bonding and defect elimination in Si (SOI)-based exfoliated Ge film. (February 2020)

• Record Type: Journal Article
• Authors: Ke, Shaoying; Zhou, Jinrong; Huang, Donglin; Wang, Ziwei; Li, Cheng; Chen, Songyan
• Is Part Of: Vacuum. Volume 172(2020)
• Publication Date: 2020-02
• Subjects: Ge/Si wafer bonding -- Poly-Ge -- By-products -- Point defects; Vacuum -- Periodicals; 621.55
• DOI: 10.1016/j.vacuum.2019.109047
• Languages: English
• ISSNs: 0042-207X

Abstract

Abstract: We report the Ge/Si wafer bonding with polycrystalline Ge (Poly-Ge) intermediate layer. The effect of the Poly-Ge layer fabricated by different methods on the transferring of the by-products at the bonded interface was investigated. The dependence of the bubble density on the Poly-Ge film thickness was also identified. Due to the high crystallinity of the Poly-Ge film fabricated by furnace, the gas formed at the bonded interface can be effectively absorbed, leading to the decrease of the bubble density. The exfoliation of the Si-based and SOI-based Ge film was successfully achieved by Smart-Cut™ technique. More importantly, the crystalline quality of the Ge film was improved by controlling the point defects in the exfoliated Ge film. Finally, the FWHMXRD of 60 arc sec for Si-based Ge film and the FWHMXRD of 111 arc sec for SOI-based Ge film, which are much lower than that of the epitaxial ones, were achieved. Highlights: We propose a new method to fabricate ultrahigh-quality Si-based and SOI-based Ge film. The poly-Ge is proved to be an excellent gas transporter to eliminate the bubbles. The lattice of Ge/Si is isolated by poly-Ge, eliminating the dislocations in Ge film. By etching the defect region in Ge film, the film quality is significantly improved. The point defects in the H + -implanted Ge film are repaired after post-annealing.