Semiconductor devices with peripheral gate structures

A semiconductor device includes a substrate including a cell region and a peripheral region, a cell gate electrode buried in a groove crossing a cell active portion of the cell region, a cell line pattern crossing over the cell gate electrode, the cell line pattern being connected to a first source/drain region in the cell active portion at a side of the cell gate electrode, a peripheral gate pattern crossing over a peripheral active portion of the peripheral region, a planarized interlayer insulating layer on the substrate around the peripheral gate pattern, and a capping insulating layer on the planarized interlayer insulating layer and a top surface of the peripheral gate pattern, the capping insulating layer including an insulating material having an etch selectivity with respect to the planarized interlayer insulating layer.