A test element group structure having 3-dimensional SRAM cell transistors includes a bulk metal-oxide-semiconductor (MOS) transistor formed at a semiconductor substrate and a first interlayer insulating layer covering the bulk MOS transistor. A lower thin film transistor is disposed on the first interlayer insulating layer, and the lower thin film transistor is covered with a second interlayer insulating layer. An upper thin film transistor is disposed on the second interlayer insulating layer, and the upper thin film transistor is covered with a third interlayer insulating layer. A metal node plug is disposed to pass through the first to third interlayer insulating layers. The metal node plug electrically connects a first impurity region of the bulk MOS transistor, a first impurity region of the lower thin film transistor, and a first impurity region of the upper thin film transistor with each other.