Oxidation of Silicon Promoted by Alkali Metals.

Oxidation of Silicon Promoted by Alkali Metals.
K.F. FRENETTE, L. LEVESQUE, B. LAMONTAGNE, D. ROY. LP AM. Département-, de Physique. Université Laval. - The study of the Si/Si02 interface is of great fundamental and technological interest. High quality oxide films of less than 100 A in thickness will be soon required to reach higher integration in microelectonics devices. To avoid excessive diffusion of impurities and dopants in these thin interfaces, silicon oxidation must be performed at temperature below 1300 K. Alkali metals are known to increase oxidation rate and then might be used to circumvent thermal oxidation. The present work dwells on simultaneous adsorption of oxygen and alkali atoms (K or Cs) on Si (111)7x7. Simultaneous adsorption was performed at different O2 pressures. XPS was used to study the evolution of alkali oxides under X-rays and thermal treatment. It was observed that X-rays affect oxygen diffusion through the K-multilayers. The formation of silicon oxide was also investigated. Finally, SIMS depth profiles and RBS measurements were made in order to monitor traces of cesium left in the substrate after its desorption at moderate temperature.