Low-temperature growth of polycrystalline Si and Ge films by ultraviolet laser photodissociation of silane and germane

Abstract

Polycrystalline Si and Ge films have been grown on amorphous SiO2 substrates (average Tsubstrate <120 °C) by the photodissociation of SiH4/N2 or GeH4/He mixtures, respectively, using pulsed ArF (193 nm) and KrF (248 nm) excimer lasers. For both Si and Ge, the film growth rate exhibited a strong dependence on laser wavelength and beam intensity I, where 1≲I⩽20 MW cm−2. As-deposited films exhibited average grain sizes of up to 0.5 μm and the grains were equiaxed with a random orientation. Ge films doped with ∼1020 cm−3 Al were obtained by the simultaneous photodissociation of Al(CH3)3 and GeH4.