REDUCTION OF PN JUNCTION LEAKAGE CURRENT BY USING POLY-SI INTERLAYERED SOI WAFERS

A new type of silicon-on-insulator (SOI) structure was fabricated by using direct bonding technology to bury multilayered films consisting of poly-Si, Si3N4, and SiO2. The cross-sectional structures were analyzed by using SIMS, micro-Raman spectroscopy, and spreading resistance methods. Both the area components and the perimeter components of the pn-junction leakage current were reduced more than 10 fold in structures that had a poly-Si interlayer just beneath the active-devices to act as a gettering site. The leakage current was a function of tensile strength in the SOI layer and was easily controlled with a suitable combination of interlayered insulators.