SIMOX WAFERS WITH LOW DISLOCATION DENSITY PRODUCED BY A 100-MA-CLASS HIGH-CURRENT OXYGEN IMPLANTER

The dislocation density and the structure of SIMOX wafers formed under different implantation conditions have been investigated using Secco etching and cross-sectional transmission electron microscopy (XTEM). The relationship between the breakdown voltage of the buried oxide layer and the oxygen dose has been studied. The dislocation density decreases as the dose decreases and the wafer temperature, during implantation, increases. The SIMOX wafer implanted at 180 keV with a low dose of 0.4 x 10(18) cm-2 at 550-degrees-C and subsequently annealed at temperatures higher than 1300-degrees-C has an extremely low dislocation density on the order of 10(2) cm-2. The buried oxide layer of this SIMOX wafer has a breakdown voltage of 40 V.