A SINGLE-TRANSISTOR SILICON SYNAPSE

We have developed a new floating-gate silicon MOS transistor for analo g learning applications, The memory storage is nonvolatile; hot-electr on injection and electron tunneling permit bidirectional memory update s, Because these updates depend on both the stored memory value and th e transistor terminal voltages, the synapse can implement a learning f unction, We have derived a memory-update rule from the physics of the tunneling and injection processes, and have investigated synapse learn ing in a prototype array, Unlike conventional EEPROM devices, the syna pse allows simultaneous memory reading and writing, Synapse transistor arrays can therefore compute both the array output, and local memory updates, in parallel, The synapse is small, and typically is operated at subthreshold current levels; it will permit the development of dens e, low-power silicon learning systems.