The increased usage of indentation testing for the determination of the toughness of brittle materials has raised many questions about the nature and extent of plastic deformation in these materials. Of particular interest is the behavior of single crystal silicon in indentation (hardness) testing. Recent studies point to some interesting properties of silicon under indentation loading and unloading. The least understood of these properties is the apparent phase change and subsequent cracking that the crystalline silicon experiences upon indentation. The pressure induced phase transformation is thought to proceed by crystalline Si changing to metallic and then changing to amorphous. Accompanying this phase transformation is usually a characteristic cracking pattern.
It is the goal of a larger study to characterize the deformation process during indentation. This can be best achieved by producing an electron transparent cross section of a microindentation which is suitable for structural characterization using a Transmission Electron Microscope (TEM). The various conventional and unconventional methods we have attempted to employ to produce suitable samples, the problems we have encountered, preliminary results, and proposed modifications are discussed.