A built-in microphone is provided in a flap hinged to a body in a closable manner. Charging of the data line is completed early so that it is possible to reduce a time required from start of the data reading to such a state that a passing current difference between the data lines reaches a level corresponding to storage data of the selected memory cell, and the data reading can be performed fast. The monitored voltage is capable of indicating the initiation of arcing from the electrosurgical instrument, such that the voltage of the radio frequency signal can be adjusted in response to the monitored voltage at the resonant frequency. This leads to a semiconductor structure having a high aspect ratio which is defined as the depth of the recess divided by the width of the semiconductor material between the recess.