Ultraviolet (UV) Irradiation Effect on Minority-Carrier Recombination Lifetime in Silicon Wafers with Oxide and Nitride Films

Abstract

ABSTRACTA new method based upon photoconductance measurement of the minority-carrier recombination lifetime is developed to investigate defects both in dielectric films and on the interface. In this method, surface recombination process in silicon substrate is used as a probe to detect the interface traps generated by ultraviolet (UV) irradiation as well as the defects in a film whose electronic state can be excited by UV irradiation. A variety of films, including native, chemical vapor deposited (CVD) and thermal oxide as well as CVD nitride, have been studied. In CVD nitride, for example, evidence is provided that K-centers, the main charge trapping defects, have a negative correlation energy (negative-U).