Investigation of silicon-on-insulator (SOI) substrate preparation using the smart-cutTM process

A promising technology called smart-cutTM process based on the hydrogen ion implantation and wafer bonding was proposed to prepare the SOI wafers. In this work, the ion implanter applied in the VLSI fabrication process, namely AMAT 9500×R, was used to implant the hydrogen ions, which were extracted from a PH3 plasma gas. The depth profile of the ion-implanted hydrogen in silicon wafers was measured by TOF-SIMS, and the result are in good agreement with the simulation result from SRIM simulator. Experimental results demonstrate that the SOI layer can be successfully transferred from the hydrogen-implanted wafer onto the handle wafer, and the thickness of the transferred SOI layer is approximate to the average projected range of hydrogen ions obtained from TOF-SIMS data. However, some bubble-like non-transferred regions appear on the surface of SOI wafers and two techniques have been reported, which may be effectively used to eliminate this phenomenon. The surface roughness was analyzed by AFM and indicated that a follow-up chemical mechanical polishing was necessary to improve the surface roughness of the SOI layer after the smart-cutTM process.