Dosimetric Silica Films: The Influence of Fields on the Capture of Positive Charge

The influence of oxide field and dose magnitude on the buildup of positive charge in dosimetric silica films has been studied in experiments using x-and gamma rays in the 0.1 to 100 Krad region. Specially-prepared metal-oxide-semiconductor (MOS) transistors and capacitors on n-type silicon were used. By the use of a normalisation method, the results have been compared with many earlier studies on MOS capacitors and commercial MOS transstors. At low fields, response rises sharply with field. At higher fields, a plateau region may or may not be followed by a region of negative slope. The relative importance of interface and bulk charge is discussed.