ELECTRON-SPIN-RESONANCE CHARACTERIZATION OF TRAPPING CENTERS IN UNIBOND(R) BURIED OXIDES

Electron spin resonance and capacitance vs. voltage measurements are u sed to evaluate the radiation response of Unibond buried oxides. When damaged by hole injection, it is found that Unibond(R) buried oxides e xhibit a rough correspondence between E' centers and positive charge a s well as generation of P-b centers at the Unibond(R) buried oxide/Si interface. In these respects, Unibond(R) buried oxides qualitatively r esemble thermal SiO2. However, a hydrogen complexed E' center known as the 74 G doublet is also detected in the Unibond(R) buried oxides. Th is defect is not detectable in thermal SiO2 under similar circumstance s. Since the presence of 74 G doublet center is generally indicative o f very high hydrogen content and since hydrogen is clearly a significa nt participant in radiation damage, this result suggests a qualitative difference between the radiation response of Unibond(R) and thermal S iO2. Unibond(R) results are also compared and contrasted with similar investigations on separation-by-implanted-oxygen (SIMOX) buried oxides . Although the charge trapping response of Unibond(R) buried oxides ma y be inferior to that of radiation hardened thermal SiO2, it appears t o be more simple and superior to that of SIMOX buried oxides.