SEMICONDUCTOR DEVICE AND METHOD OF FABRICATING THE SAME

摘要

A semiconductor memory device includes a transistor having a channel region buried in a substrate and source/drain regions formed to provide low contact resistance. A field isolation structure is formed in the substrate to define active structures. The field isolation structure includes a gap-fill pattern, a first material layer surrounding the gap-fill pattern, and a second material layer surrounding at least a portion of the first material layer. Each active structure includes a first active pattern having a top surface located beneath the level of the top surface of the field isolation structure, and a second active pattern disposed on the first active pattern and whose top is located above the level of the top surface of the field isolation structure.