Characterization of silicon dioxide film by high spatial resolution cathodoluminescence spectroscopy

Abstract

We have measured the cathodoluminescence (CL) spectra of silicon dioxide (SiO2) films prepared by a variety of methods and observed peaks at 280, 445, 480, 520, and 640 nm. A comparison of the CL and electron spin resonance spectra of Si-doped quartz glass showed that the 445 and 480 nm peaks originated from oxygen vacancy centers, which were different from E′ centers. From CL measurement of a cross section of thermally grown SiO2 film deposited on a Si substrate, we found that the relative intensities of the 445 and 480 nm peaks were stronger than that of the CL peak at 640 nm. This CL peak was attributed to the nonbridging oxidation hole centers or their precursors. Furthermore, CL measurement of a cross section of a 16 M dynamic random-access memory device revealed that the relative intensity in the gate oxide film was stronger than that in the interlayer oxide film. These data suggest that the content of oxygen vacancy centers increases in the vicinity of the interface between the SiO2 film and the Si substrate relative to that of the nonbridging oxidation hole centers. CL spectroscopy provides us with a large amount of data on defects in the SiO2 film of Si-based electronic devices at the 0.1 μm level.