Solid phase epitaxy of amorphous Si films by suppression of surface SiO2 layer formation using heating-up under Si2H6 gas environment

Abstract

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