DEFECTS IN SIO2 SI STRUCTURES PROBED BY USING A MONOENERGETIC POSITRON BEAM/

Defects in SiO2/Si specimens were probed by using a monoenergetic posi tron beam. Doppler broadening profiles of the annihilation radiation w ere measured as a function of incident positron energy for SiO2(100 nm )/Si specimens fabricated by wet, dry and ultradry oxidation. The diff usion of positrons in the Si substrate was found to be enhanced by an electric field caused by positive charges near the SiO2/Si interface. The Doppler broadening profile corresponding to the annihilation of po sitrons in the Si substrate with the SiO2 film grown by wet oxidation was found to be broader than those in the specimens fabricated by dry or ultradry oxidation. This was attributed to the fact that the concen tration of oxygen clusters in the Si substrate for the specimen fabric ated by wet oxidation was higher than those for the specimens fabricat ed by dry or ultradry oxidation.