Mechanical Properties of Mono-crystalline Silicon Thin Films Measured by Different Methods

In order to investigate the reliability of the mechanical properties of mono-crystalline silicon thin films (thickness of 5 mum), a uniaxial tensile test and a nanoindentation test were conducted, respectively, on samples of identical composition and under identical conditions. The tensile samples were 100 mum long, 50 mun wide, and microfabricated on the silicon-on-insulation (SOI) wafer. It was founded that for mono-crystalline silicon thin films, using tensile test can measured Young´s modulus on main crystallographic orientations independently, and <-110> orientation has a slightly higher Young´s modulus than <100> orientation for both Si(001) and Si(110) films. From the nanoindentation test, measured Young´s modulus slightly varied with provided Poisson´s ratio, and Si(110) films have slightly superior mechanical properties to Si(001) films. Young´s modulus of silicon thin films measured by different testing methods does not differ significantly