Decomposition of trimethylaluminum and N2O on Si surfaces using ultraviolet laser photolysis to produce Al2O3 films

Abstract

In order to investigate the initial deposition process of Al2 O3 layers on Si surfaces, trimethylaluminum (TMA), and N2 O were introduced on clean Si(111) wafers, and the surface reaction was analyzed by x-ray photoelectron spectroscopy. The irradiation effects of an ArF excimer laser on the gases and substrates were also studied. TMA was adsorbed on clean Si(111) surfaces at room temperature, and then Si–C bonds were easily formed at an annealing temperature of 600 °C. On the other hand, if a few oxide layers were formed on clean Si surfaces, TMA bound with O atoms and Si–C layers did not appear after annealing. Although carbon impurities still remained in the deposited layers, the carbon concentration was reduced by preoxidation of the Si surface and photolysis of TMA with laser irradiation. Moreover, it was found that Al2 O3 layers without carbon atoms could be prepared using an N2 O photolysis reaction process after decomposition of TMA on preoxidized Si surfaces.