Observations on phosphorus stabilized SiO2films

Two experiments were performed with phosphorus stabilized and untreated silicon dioxide films on silicon substrates. In the first, the interaction of phosphorus and boron was studied; it was found that diffusion of boron over a phosphorus stabilized film destroyed its stabilization against ion drift effects at 400°C, but that diffusion of phosphorus over a boron diffused film resulted in a stabilized oxide. In the second experiment, a slowly varying voltage was applied at 600°C to a silicon-silicon dioxide-gold structure and the current through the oxide film was recorded. Both phosphorus stabilized and untreated silicon dioxide films show rectifying characteristics, the more highly conducting direction being that with the silicon negative. In the case of the untreated film, a large peak of current is superimposed on this characteristic at -2.5 volts. This peak is absent in phosphorus stabilized films. Discharge currents equivalent to the charging currents are not observed on removing voltage from the specimen, as they are at 400°C. Five distinguishable types of charge transfer in silicon dioxide films are tabulated, and compared with those described in the literature as occurring in crystal quartz.