A non-volatile memory device includes a semiconductor substrate including a cell array region and a peripheral circuit region. A first cell unit is on the semiconductor substrate in the cell array region, and a cell insulating layer is on the first cell unit. A first active body layer is in the cell insulating layer and over the first cell unit, and a second cell unit is on the first active body layer. The device further includes a peripheral transistor on the semiconductor substrate in the peripheral circuit region. The peripheral transistor has a gate pattern and source/drain regions, and a metal silicide layer is on the gate pattern and/or on the source/drain regions of the peripheral transistor. A peripheral insulating layer is on the metal silicide layer and the peripheral transistor, and an etching protection layer is between the cell insulating layer and the peripheral insulating layer and between the metal silicide layer and the peripheral insulating layer.