Nanomechanical Properties of Standard and Strained SOI Films Fabricated by Wafer Bonding and Layer Splitting

Abstract

Biaxial tensile strained Si layers grown epitaxially on SiGe have attracted renewed attention for high performance CMOS devices. Strain engineering for mobility enhancement is an attractive option to improve CMOS device performance. Epitaxial Si1-xGex and most recently Ge-free bi-axially strained sSOI are among the serious candidates for higher mobility channel material. We demonstrate how the fabrication of thin single crystal Si devices by wafer bonding and hydrogen ion cut film exfoliation technique is affecting their nanomechanical properties compared to bulk single crystal Si. Although both the handle wafer and the bonded thin device layer are single crystal Si, it turns out that their nanomechanical properties differ considerably. Using nanoindentation, we measured the properties of SOI and bi-axially tensile strained sSOI and benchmarked the results against single crystal bulk Si. The experimental results indicate that the hardness of the strained thin Si films varies significantly.