Abstract: The present disclosure provides a method for manufacturing a semiconductor memory device. Because the present method includes applying a dopant-implanted layer on a semiconductor memory substrate before growing a silicon nitride layer on the substrate, the silicon nitride layer can be grown at an increased rate. The present disclosure avoids a problem encountered in the prior art wherein a seam having a greater length contacts an edge of a contact plug of a semiconductor memory device. Hence, a leakage problem at subsequent operations of semiconductor manufacture can be avoided, and the product yield can be significantly improved.