Uniaxially strained SiGe(111) and SiGe(100) grown on selectively ion-implanted substrates

Abstract Selective ion implantation method, which can induce uniaxial strain into Si/Ge heterostructures, is applied to both SiGe/Si(111) and SiGe/Si(100). The effect of ion implantation on the strain relaxation enhancements is confirmed for the SiGe(111). With optimal implantation conditions, the local strain control is realized, and anisotropic strain states are obtained. However, the anisotropy of the strain states in SiGe(111) is much smaller than SiGe(100) due to the dislocation structure. Since the one direction dislocations are unlikely to be generated in SiGe(111), the obtained uniaxial strain is considered to be induced by elastic effect. In contrast, one direction arrays of dislocations are clearly observed for SiGe(100), which indicates that the uniaxial strain induced in SiGe(100) is caused by plastic relaxation. It can be, therefore, concluded that the SiGe(100) is more suitable for obtaining the uniaxial strain than SiGe(111) and that high mobility uniaxially strained channel devices are expected to be realized based on this technique.