N-channel FET with storage properties - has junction region adjacent drain sufficiently thin as to be non-conductive at specified potential conditions

摘要

The field-effect transistor has source and drain as terminal connecting regions and a floating storage gate surrounded alround by an insulator. When programmed by a channel injection of electrons, heated by a heavy source-drain field, the gate is negatively charged, as the electrons penetrate the insulator. An n-doped junction region, thinner than the source or drain is provided at the channel end between the source or drain and a channel section under the storage gate. Over the latter is insulatingly formed a control gate as in 2636350. The drain (D) adjacent junction region (BD) is so thin as to be non-conductive at the most positive drain potential (+25V), at the most negative control potential (OV) and at normal substrate potential (biasing voltage of -5V).