Local uniaxial tensile strain in germanium of up to 4% induced by SiGe epitaxial nanostructures

We show that a relatively simple top-down fabrication can be used to locally deform germanium in order to achieve uniaxial tensile strain of up to 4%. Such high strain values are theoretically predicted to transform germanium from an indirect to a direct gap semiconductor. These values of strain were obtained by control of the perimetral forces exerted by epitaxial SiGe nanostructures acting as stressors. These highly strained regions can be used to control the band structure of silicon-integrated germanium epilayers. (C) 2015 AIP Publishing LLC.