High speed and improved reliability of thermally-assisted programming for gate-all around junctionless NOR flash memory

Abstract

This study demonstrated the thermally-assisted (TA) fast programming of a NOR flash memory device, employing a gate-all-around (GAA) structure with a junctionless (JL) silicon nanowire (SiNW) wrapped by oxide-nitride-oxide (ONO) gate dielectrics. Fast programming was achieved with the use of instantaneous thermally excited electrons driven by Joule heat, which was generated in a homogeneously heavily doped SiNW by a voltage difference between the source and drain. Its programming speed is the fastest among var-ious NOR flash memory ever reported. This programming mechanism is based on channel hot-electron (CHE) injection, which has been widely used as a programming method for NOR flash memory. Normally, this CHE injection method inevitably degrades the quality of the tunneling oxide. The proposed thermally-assisted channel hot electron (TA-CHE) not only improves the programming speed of the NOR flash memory, but also provides simultaneous curing of damaged tunneling oxide because of silicon nanowire channel tem-perature increment induced by Joule heat.