A Novel Fluorine Incorporated Band Engineered (BE) Tunnel (SiO2/ HfSiO/ SiO2) TANOS with Excellent Program/Erase & Endurance to 10^5 Cycles

Abstract

We demonstrate for the first time a fluorine incorporated band- engineered (BE) tunnel oxide (SiO 2 /HfSiO/SiO 2 ) TANOS with excellent program / erase (P/E) characteristics and endurance to 10 5 cycles. Incorporating fluorine in the tunnel dielectric improves Si/SiO 2 interface resulting in excellent endurance of nearly constant over 3 V P/E window for at least 10 5 cycles. Fluorine also reduces interface state generation during retention by ~20%. Furthermore, Fluorine passivates bulk traps leading to as much as ~10times higher charge to breakdown (Q bd ) and ~10-50times lower interface state density (Dit). Fluorine passivation for BE-TANOS is significant because it improves reliability assisting implementation of TANOS flash NVM beyond the 20 nm node.