Formation of a defect-free junction layer by controlling defects due to As/sup +/ implantation

A method of suppressing defects related to knock-on has been developed through the use of a Si/sub 3/N/sub 4/ film as an implementation mask. In MOS devices with LDD structures, junction leakage is caused by the dislocation lines from the sidewall edge. Two requirements are needed to suppress the growth of the dislocation lines: the elimination of stress from the sidewall edge and the elimination of dislocation loops due to As/sup +/ implantation. The growth of dislocation loops is affected by the presence of recoiled oxygen atoms from implantation through SiO/sub 2/ films. However, when a Si/sub 3/N/sub 4/ mask is used as an implantation mask, the amount of recoiled nitrogen atoms is two orders of magnitude lower in comparison to the recoiled oxygen atoms for a SiO/sub 2/ mask, and the dislocation loops disappear during heat treatment. Consequently, defects are not generated and the junction leakage failures due to residual defects disappear.<>