Highly oriented crystalline Si on epitaxial Gd2O3/Si(111) substrate using low-cost radio frequency sputtering for Silicon on Insulator application

Abstract

Silicon-on-Insulator (SOI) technology has been the center of attraction with the advancement in Radio Frequency (RF) technology and the advent of Internet-of-Things due to its low-power operation with reduced parasitic and short-channel effects. However, the state-of-the-art smart-cut method used for the SOI wafer is costly. Alternatively, the notion of using the Si channel layer on epitaxial rare-earth oxide has been proposed. In literature, the existing techniques used to achieve the same, such as Molecular beam Epitaxy or reduced-pressure chemical vapor deposition technique, are either costly or non-high-volume manufacturable. In this context, we propose a method to fabricate the highly oriented crystalline Si(111) channel layer (Top-Si) on an epitaxial Gd2O3/Si(111) virtual substrate (SOXI) utilizing the solid phase epitaxy using the high-volume manufacturing friendly (HVM), low-cost RF magnetron sputtering technique. First, we have shown the multicrystalline Si and epitaxial Gd2O3 layer grown on Si(111) substrate, as confirmed using high-resolution X-ray diffraction (HRXRD) and Transmission Electron Microscopy (TEM). Second, we investigated the impact of rapid thermal annealing at 850 °C on the heterostructure using HRXRD and TEM. It is observed that the high-temperature annealing transforms the Top-Si layer into the highly oriented crystalline Si(111) layer by fusing smaller grains towards larger grains. Hence, we demonstrate a low-cost, HVM-friendly technique for the fabrication of SOXI wafers.