Method for growing single crystalline silicon with intermediate bonding

Abstract

A method is provided for epitaxially growing single crystalline silicon on a silicon substrate (10) from a silicon-bearing gas (26) at a temperature below the pyrolytic threshold of the gas and at temperatures below those normally required for epitaxial growth. An oxidized silicon substrate (10) is fluorinated (equation 2, FIG. 2) to replace the silicon-oxide layer with an adsorbed fluorinated layer. The substrate is placed in a laser photo-CVD reactor chamber (20), the chamber is evacuated to a sub-UHV level of 10.sup.-3 to 10.sup.-7 Torr, the substrate is heated to 570.degree. C., hydrogen gas (24) is introduced into the chamber, and excimer pulsed ultraviolet laser radiation (32 from laser 12) is applied through the hydrogen gas to impinge the wafer substrate. The combined effect removes regrown native oxide and removes the adsorbed fluorinated layer and breaks the hydrogen into atomic hydrogen such that the latter bonds with the silicon in the substrate and replaces the adsorbed fluorinated layer with silicon-hydrogen bonds (equation 4, FIG. 2). The substrate is maintained at 570.degree. C. and disilane is introduced into the chamber, and excimer pulsed ultraviolet laser radiation is applied through the disilane gas to impinge the wafer substrate. The combined effect breaks the silicon-hydrogen bond and decomposes the disilane to silane and an unstable intermediate SiH.sub.z which decomposes to hydrogen and atomic silicon (equation 5, FIG. 2), which atomic silicon bonds to the now unbonded silicon in the substrate to epitaxially grow single crystalline silicon.