A wood concrete composite system has a wood construction component, an intermediate layer and a concrete construction unit. , as well as low water absorption and capability to give a pattern with favorable configuration. These steps result in a device structure having a first J-FET with the n-type source areas 7 and the n-type substrate 1 as a source and drain and the first gate areas 3 at the right and left in the figure as a gate; and the second J-FET with the n-type source areas 7 and the n-type substrate 1 as a source and drain and the second gate areas 6 and the third gate area 8 as a gate.