DUAL ELECTRON INJECTOR STRUCTURE AND SEMICONDUCTOR MEMORY DEVICE INCLUDING A DUAL ELECTRON INJECTOR STRUCTURE

摘要

A DEIS (Dual Electron Injector Structure) EAROM (Electrically Alterable Read Only Memory) device has a silicon-rich, silicon dioxide region 5 between the dual injector regions (1,3). The region (5) has an excess of silicon therein which is less than the excess of silicon in the injector regions (1,3). The device differs from known DEIS EAROM devices in that the insulator layer between the injectors is rendered conductive to a desired degree by causing a compound insulator like SiO2 to be off-stoichiometry during deposition so that the resulting insulator becomes silicon rich. Alternatively, the insulator may be deposited together with material which renders the insulator conductive or a metallic specie may be added to the insulator by diffusion or ion implantation after the insulator is formed. The resulting slightly conductive insulator provides a means for draining off trapped charge in the insulator resulting in a device of such improved cyclibility that the DEIS EAROM can be used as a Non-Volatile Random Access Memory (NVRAM) capable of from 108 to greater than 1010 cycles before threshold collapse occurs. The conductive insulator is designed so that it is conductive only at high electric fields encountered during writing and erasing and highly blocking at low fields encountered during reading or storage operations.