WAVELENGTH DEPENDENCE IN PHOTOCHEMICAL VAPOR-DEPOSITION OF ALUMINUM FILM USING DIMETHYLALUMINUM HYDRIDE

In photochemical vapor deposition of aluminum film on silicon using dimethylaluminum hydride, (CH3)2AlH, a surface reaction dominated below a (CH3)2AlH pressure of 0.3 m Torr at 200-degrees-C, which was induced only with the 160 nm band emitted from a deuterium lamp. A gas-phase reaction occurred above 0.3 m Torr at 200-degrees-C, which could be induced by both 160 nm and 240 nm emission bands from the lamp. To distinguish between surface ad gas-phase reactions, a thickness profile was used. At 240-degrees-C the surface reaction could be induced even by the 240 nm band, while the deposits formed under illumination of the two bands were thinner than those obtained with only the 240 nm band, indicating occurrence of vacuum ultraviolet (VUV)-enhanced desorption. The mechanism responsible for the observed wavelength dependence is unclear. The electrical resistivity of the films deposited at 200-degrees-C was 4.5-mu-OMEGA cm, which did not change with wavelength.