Electron spin resonance characterization of trapping centers in unibond® buried oxides

Electron spin resonance and capacitance vs. voltage measurements are used to evaluate the radiation response of Unibond buried oxides. When damaged by hole injection, it is found that Unibond® buried oxides exhibit a rough correspondence between E1 centers and positive charge as well as generation of Pb centers at the Unibond® buried oxide/Si interface. In these respects, Unibond® buried oxides qualitatively resemble thermal SiO₂. However, a hydrogen complexed E' center known as the 74 G doublet is also detected in the Unibond® buried oxides. This defect is not detectable in thermal SiO₂ under similar circumstances. Since the presence of 74 G doublet center is generally indicative of very high hydrogen content and since hydrogen is clearly a significant participant in radiation damage, this result suggests a qualitative difference between the radiation response of Unibond® and thermal SiO₂. Unibond® results are also compared and contrasted with similar investigations on separation-by-implanted-oxygen (SIMOX) buried oxides. Although the charge trapping response of Unibond® buried oxides may be inferior to that of radiation hardened thermal SiU2, it appears to be more simple and superior to that of SIMOX buried oxides.