Stress-strain engineering of single-crystalline silicon membranes by ion implantation: Towards direct-gap group-IV semiconductors
Mateus G. Masteghin, Vivian Tong, E. Schneider, Cameron C. L. Underwood, Tomas Peach, B. N. Murdin, R.P. Webb, S. K. Clowes, David Cox
Abstract
The introduction of strain into semiconductors offers a well-known route to modify their band structure. Here, we show a single-step procedure for generating such strains smoothly and deterministically, over a very wide range, using a simple, easily available, highly scalable, ion implantation technique to control the degree of amorphization in and around single-crystal membranes. The amorphization controls the density of the material and thus the tension in the neighboring crystalline regions. We have demonstrated up to 3.1% biaxial tensile strain and 8.5% uniaxial strain in silicon, based on micro-Raman spectroscopy. This method achieves strain levels never previously reached in mesoscopic defect-free, crystalline silicon structures. The flexible, gently controllable, single-step process points toward very high mobility complementary metal-oxide-semiconductor devices and easy fabrication of direct-bandgap germanium for silicon-compatible optoelectronics.