Laser Induced Photochemical Vapor Deposition of Tungsten on Silicon

An ArF excimer laser (193 nm) aligned parallel to the substrate has been used to initiate photo-activation of the W-CVD process. W was deposited on silicon and SIMOX at a 310 °C substrate temperature using WF6 as a W precursor, together with H2. The samples were analyzed after deposition with SEM and 2 MeV He+ RBS, to obtain information about the reaction between WF6 and Si in laser-induced CVD of W. The data indicate that the reaction between WF6 and Si is suppressed upon laser irradiation. The suppression increases with increasing laser-pulse frequency. An explanation for this phenomenon is given in terms of atomic Hformation after (partial) photodissociation of WF6.