Increased critical thickness for high Ge-content strained SiGe-on-Si using selective epitaxial growth

摘要

The onset of misfit dislocation formation, i.e., the critical thickness for heteroepitaxy, is studiednfor selective epitaxial growth of high Ge-content, strained SiGe on oxide-patterned Si wafers.nMisfit dislocation spacing was analyzed as a function of film thickness using plan-viewntransmission-electron microscopy. For selective epitaxial growth at 450 °C, the critical thickness fornSi0.33Ge0.67 is found to be 8.5 nm. This is a twofold increase compared to the 4.0 nm theoreticalnequilibrium critical thickness and the 4.5 nm critical thickness measured for growth on bare Sinwafers. The misfit dislocation density for selective epitaxial growth is strongly influenced by thenshape and orientation of the growth area. © 2010 American Institute of Physics.nu0004doi:10.1063/1.3530433