A press-fit space is formed between a hole end wall portion of a stator core and a closing end wall portion of a stopper, which are axially opposed to each other in a press-fit hole of the stator core. The oxide region operates to reduce a tunneling effect in a tunnel region underlying a drain region, during an OFF-state of the TFET. Accordingly, the circulation water is not continuously supplied during the rinsing step, thus it is capable of preventing bubbles from being generated caused by continuously supplying the circulation water. The fabric layers are formed into a cell-like structure when the multilayer structure is disposed at the expanded state. In a particular embodiment, the pulse width of the pulse corresponds to an applied current level that exceeds a critical current to enable data to be written to an element of the memory but does not exceed a predetermined threshold.