Effect of UV-irradiation on metal-semiconductor systems during thermal annealing

The effect of light quanta with λ= 312.5; 365.0 and 552.0 nm (hν= 3.96; 3.39 and 2.25 eV respectively) in vacuum 5·10-5 Pa on phase transformations occurring in Ti-Si, V-Si, Zr-Si systems under simultaneous thermal annealing conditions has been investigated. The annealing temperature was T = 500 0C, treatment time τ = 5, 10, 15 and 30 min. The radiant emittance set up 0.01 and 0.05 J/cm2. Depending on annealing time different oxides and silicides are formed during thermal annealing metal-semiconductor systems. Combined treatment make possible to get different oxides and silicides depending on the wavelength and annealing time. Made studies showed that system phase compositions are changed depending on incident light quantum energy and different oxides and silicides are formed while other annealing parameters are equal.The oxygen of metal-silicon systems (in the main adsorbed by metal film during deposition) is in triplet paramagnetic state. When heated films of refractory metals are radiated by hν = 3.96 and 2.25 eV photons, the absorption of radiation goes, the energy of system increases, oxides with higher content of oxygen are formed.The surface layer oxygen converts in singlet state. This change is described with help diagram level energy some state electrons oxygen. During influence on systems the radiation with hν = 3.39 eV photons absorption the energy by oxygen occurs. As a result, the oxygen transmits into the lowest triplet state that is characterized weak chemical activity.The experiments showed, as the annealing time rises, higher photon flux density is needed for suppression the oxidizing processes in metal-silicon compositions.Thus combined treatment of refractory metal-silicon with UV-irradiation allows receiving specific phase composition of systems with certain characteristic, depending parameters and conditions treatment