Hot-electron capture for CHEI programming in SONOS-type flash memory using high- κ trapping layer

Abstract

In this paper, electron-energy- and lattice-temperature-dependent hot-electron-capture properties have been investigated for polysilicon-oxide-nitride-oxide-silicon-type Flash memories using a Si3N4 and high-dielectric-constant (k) ZrO2/HfO2 charge trapping layer when channel hot-electron injection is applied for programming. Hot-electron-capture rate is extracted by using an electrical method for various devices, and its lattice-temperature dependence indicates that inelastic phonon scattering may be the dominant mechanism of hot-electron relaxation. Memory device using a ZrO2 charge trapping layer shows enhanced electron capture from extended SixZr1-x) O2 interface of ∼2 nm due to more sufficient scattering, and the programming speed of ZrO2 device is enhanced as compared to HfO2 by × 2.2 times and by ∼3.2 times. Capabilities of low-voltage operation and improved endurance property are also demonstrated for ZrO2 device as compared to the other contending NOR -type devices. © 2008 IEEE.