Defect reduction of selective Ge epitaxy in trenches on Si(001) substrates using aspect ratio trapping

Abstract

Defect-free germanium has been demonstrated in $\mathrm{Si}{\mathrm{O}}_2$ trenches on silicon via Aspect Ratio Trapping, whereby defects arising from lattice mismatch are trapped by laterally confining sidewalls. Results were achieved through a combination of conventional photolithography, reactive ion etching of $\mathrm{Si}{\mathrm{O}}_2$ , and selective growth of Ge as thin as $450\mathrm{nm}$ . Full trapping of dislocations originating at the $\mathrm{Ge}∕\mathrm{Si}$ interface has been demonstrated for trenches up to $400\mathrm{nm}$ wide without the additional formation of defects at the sidewalls. This approach shows great promise for the integration of Ge and/or III-V materials, sufficiently large for key device applications, onto silicon substrates.