Finite Element Modeling and Raman Study of Strain Distribution in Patterned Device Islands on Strained Silicon-on-Insulator (sSOI) Substrates

Abstract

Finite Element (FE) Analysis was performed to study the strain relaxation of the strained Si on insulator (sSOI) wafers with different patterned size and thickness of the sSi layer. The results from FE simulation corroborate the experimental results from Raman microprobe spectroscopy. For patterned device islands without capping the biaxial tensile strain (in-plane strain either in X or Y direction) in the sSOI layer may relax completely when the sSOI device island size shrinks below a critical geometry. As the size of quadratic device islands is steadily decreased, the dominant relaxation effects at the corners overlap and spread until they span the entire device structure. Finite Element Analysis provides a detailed understanding of the strain distribution and demonstrates the evolution of strain relaxation from the pattern corners and island edges to eventually encompass the entire device island for very small subcritical geometries.