UV Light-Assisted Deposition of Al on Si from TMA

Abstract

Recently, in the field of microelectronic devices, a lot of investigations have been concerned with laser-induced deposition of metal films on semiconductor or insulating substrates (1-3). More precisely the localized deposition (micron scale) of aluminum on silicon or on silica from laser- assisted CVD is of great interest for maskless device fabrication techniques (4) as well as for circuit mask repair (5). Up to now, several authors have demonstrated that a two-step process consisting of surface nucleation followed by growth was needed to deposit A1 thin film on Si and SiO2 substrates (see Table 1). Among them, Tsao et al. (6) used a focused cw ultraviolet (frequency-doubled Ar ion laser) irradiation followed by a cw infrared CO2 laser irradiation, triisobutylaluminum (TIBA) being the gaseous source. Following the same idea, Bouree et al. (7) first illuminated a flow of trimethylaluminum (TMA) molecules with UV light (mercury lamp) and then submitted the sample to a focused cw visible Ar ion laser irradiation. In these two examples, the two-step process was performed by using two different light sources. Higashi et al. (8) used a similar approach with only one light source, namely a pulsed UV (KrF excimer) laser while heating the substrate up to 200°C.