Mos type nonvolatile memory device

Abstract

Abstract PURPOSE:To obtain the nonvolatile memory having stable characteristics by forming a diffused layer having higher density than a substrate and the same type as the substrate partly in contact with the drain of a double gate MOSFET in a channel region and reducing the breakdown voltage between the diffused layer and the drain lower than the negative resistance generating voltage of the FET in a writing mode. CONSTITUTION:There are formed on the main surface of a P type Si 1 a field oxide film 3, a gate oxide film 4, a P-added polysilicon floating gate 5, a film 6 oxidized on the surface of the polysilicon 5, and a P-added polysilicon controlled gate 7. An N type source 8 and drain 9 are formed thereon, openings 10-12 are selectively perforated, and aluminum electrodes are provided therethrough. A P<+> type layer 16 is partly formed in the channel in contact with the drain 9, and the withstand junction voltage between the drain 9 and the layer 16 is set lower than the negative resistance generating voltage of the memory FET in case of writing operation mode. Even if the substrate and the source are grounded and sufficiently high voltage is applied to the controlled gate and the voltage of the same polarity is applied to the drain (in writing) no negative resistance occurs and discrete excessive writing phenomenon does not occur according to this configuration.

Inventors

• 👤 Masanori Kikuchi

Bibliographic Details