SEMICONDUCTOR DEVICES HAVING CELL ARRAY AND PERIPHERAL REGIONS THEREIN

A semiconductor device includes a substrate having first and second active patterns therein, which are spaced apart from each other. The first active pattern has a top surface that is elevated relative to a top surface of the second active pattern. A channel semiconductor layer is provided on the top surface of the first active pattern. A first gate pattern is provided, which includes a first insulating pattern, on the channel semiconductor layer. A second gate pattern is provided, which includes a second insulating pattern having a thickness greater than a thickness of the first insulating pattern, on the top surface of the second active pattern.