Suppression of surface SiO2 layer and solid phase epitaxy of amorphously deposited Si films using heating-up under Si2H6 environment

Abstract

A novel technique to realize a selectively grown Si epitaxy layer has been developed. This technique consists of deposition of amorphous Si with oxide-free Si surface, selective solid phase epitaxial (SPE) growth on Si windows, and etching of uncrystallized amorphous Si on SiO2 layer. Formation of surface oxide can be effectively suppressed by flowing Si2H6 gas during heating-up stage to the deposition temperature. This method enables us to grow epitaxial layer without any high temperature cleaning procedures. Substantially higher growth rate of vertical SPE on Si windows over lateral SPE on SiO2 regions allows the growth of thick SPE layer with a minimized lateral overgrowth. With a proper etching solution. the remaining amorphous Si on SiO2 layer can be readily etched to form a selectively defined epitaxial layer on Si windows.