Abstract: A semiconductor device is composed of a first IC chip having a data processing function and a second IC chip having a non-volatile memory for storing confidential reference data. Both of the IC chips are provided with connection pads on the facing sides of the two chips, so that they can be bonded in a chip-on-chip configuration. Each of the connection pads of the second IC chip is located at the position of a corresponding connection pad of the first IC chip. An externally input data is compared with the reference data for verification. The input data is authenticated based on the result of the verification.

Abstract: A method for making a nonvolatile memory device having a field effect transistor for storing information, and a Schottky diode in series with the field effect transistor. The field effect transistor includes source and drain regions in a semiconductor substrate, with a channel region interposed between them and a gate electrode above the channel region. A ferroelectric gate film is sandwiched between the channel region and the gate electrode. In the method, a conductive barrier meterial is deposited in contact with the source region of the field effect transistor to make the Schottky diode. In reading information from the memory device, voltage is applied to a serial circuit consisting of the field effect transistor and the Schottky diode to turn the Schottky diode on.