Contents I. Introduction
Flash memory has the advantage of nonvolatility over DRAM, but has much slower program/erase speed and requires higher operating voltages. In a conventional flash memory device programmed by hot-electron injection, electrons must have energy close to or higher than that of the oxide barrier (3.15 eV) to be injected into the floating gate. A very small percentage of electrons in the channel have such high energy [1], so the current injected into the floating gate is very small, resulting in slow programming speed. High voltages are required to produce these hot electrons, so that it is difficult to scale the program/erase voltages with the technology node. A low-barrier tunnel dielectric is necessary to improve programming efficiency and speed with the possibility of reducing the operating voltages.
