Semiconductor memory device

Abstract

A method of manufacturing a semiconductor memory device and a semiconductor memory device, the method including providing a substrate that includes a cell array region and a peripheral circuit region; forming a mask pattern that covers the cell array region and exposes the peripheral circuit region; growing a semiconductor layer on the peripheral circuit region exposed by the mask pattern such that the semiconductor layer has a different lattice constant from the substrate; forming a buffer layer that covers the cell array region and exposes the semiconductor layer; forming a conductive layer that covers the buffer layer and the semiconductor layer; and patterning the conductive layer to form conductive lines on the cell array region and to form a gate electrode on the peripheral circuit region.