ATOMIC LAYER GROWTH OF SILICON BY EXCIMER LASER-INDUCED CRYOGENIC CHEMICAL VAPOR-DEPOSITION

Polycrystalline silicon has been grown by ArF excimer laser (193 nm) induced dissociation of Si2H6 adsorbed on a quartz substrate cooled to -69°C. Silicon atomic layer growth has also been achieved by controlling the Si2H6 adsorbed layer thickness. It is found that the chemical reactivity of the first one monolayer of Si2H6 in contact with the growing Si surface is extremely high compared to that of the second or third Si2H 6 layer. The effective photodissociation reaction rate at 193 nm for the first Si2H6 layer is estimated to be more than 40 times faster than that of an isolated Si2H6 molecule. Such high reactivity of the first monolayer is a possible mechanism of the self-limiting process in the atomic layer growth.