Effect of gas adsorption on the segregation behavior of substrate Cu on Ti film

Effect of gas adsorption on the segregation behavior from a substrate Cu to the top surface of a deposited Ti film was studied by Auger electron spectroscopy. At an ambient pressure of2 × 10−7Pa, Cu segregated on the top surface of Ti film by heating above 700 K. Below 690 K, no segregation was observed. Furthermore, even at 720 K, the segregation of Cu was prevented by introducing oxygen up to a pressure of2 × 10−6Pa. The segregation behavior of Cu was examined as a function of the surface concentration of adsorbed oxygen and temperature. Cu segregation was observed for oxygen concentrations less than 8 at%, while no segregation was observed for the concentration of oxygen higher than 11 at%. Although temperature might be a factor keeping the segregation under control below 690 K, the surface concentration of oxygen appears to be an important factor for the segregation behavior.