Semiconductor memory device having shield layer between peripheral circuit and cell array structures

Abstract

Disclosed are semiconductor memory devices and their fabrication methods. The semiconductor memory device comprises a peripheral circuit structure including peripheral circuits on a semiconductor substrate and a first dielectric layer on the peripheral circuits, a cell array structure on the semiconductor substrate, and a shield layer between the peripheral circuit structure and the cell array structure. The cell array structure includes bit lines, first and second active patterns on the bit lines, first word lines that extend in a second direction on the first active patterns, second word lines that extend in the second direction on the second active patterns, data storage patterns on the first and second active patterns, and a second dielectric layer on the semiconductor substrate. A hydrogen concentration of the first dielectric layer is greater than that of the second dielectric layer.