Fabrication of Silicon on Diamond (SOD) substrates by either the Bonded and Etched-back SOI (BESOI) or the Smart-Cut™ technology

In this paper, Silicon on Diamond (SOD) substrates were fabricated using the direct bonding process in two different technologies: the BESOI (Bonded and Etched-back SOI) and the Smart-Cut™ process. The polycrystalline diamond (C∗) film deposited by Chemical Vapor Deposition assisted by Microwave Plasma (MPCVD) was planarized by an innovative process which induces a significant decrease of the diamond surface roughness (1.2 nm for the 200 nm diamond layer). The planarization method as well as the entire SOD substrate process by the BESOI or the Smart-Cut™ technology are described in the paper. Cross sectional high-resolution transmission microscopy reveals the good quality of the future silicon channel on top of the thin diamond layer.