RELATIONSHIP BETWEEN THE LOCATION OF TRAPPED HOLES AND INTERFACE STATE GENERATION IN THE Si-SiO//2 SYSTEM.

Studies based on the hole-profiling experiments of S. T. Chang and S. A. Lyon (Appl. Phys. Lett. 48, 136, 1986) are discussed. They found two different trapping positions for holes introduced by X-irradiation and Fowler-Nordheim tunneling. The two types of trapped holes could also be distinguished by their response to photoinjected electrons. In the present experiments it is shown that these two trapping sites are not unrelated defects, but rather they are two different stages in the evolution of a trapped hole. In particular, it was found that the one-to-one correlation of interface states with trapped holes, the suppression of interface state formation by annihilation of the trapped holes, and the generation of interface states by hole annihilation are all limiting cases of a more complicated behavior. Even after reaching the vicinity of the Si/SiO//2 interface, a radiation-produced hole must pass through several stages before becoming an interface state.