Material properties of plasma-thinned bonded SOI wafers

Gate-oxide breakdown measurements were made to determine the quality of the Si surface of plasma-thinned Si wafers. Circular MOS capacitors having a thermal oxide of 190 A were fabricated on unprocessed bulk Si wafers and plasma-thinned wafers. The distribution of gate-oxide breakdown voltages for 250-/spl mu/m diameter MOS capacitors fabricated on a bulk Si wafer and on a plasma-thinned bulk Si wafer are shown. The similarity between the breakdown distributions is an indication that the AcuThin wafer thinning process does not degrade the Si surface quality. Based on these and other results to be presented, we believe that this plasma etching process for thinning bonded Si wafers does not cause any surface or subsurface damage which could adversely impact device performance, i.e., it preserves the bulk silicon material qualities.<>