Flash memory devices using large electron affinity material for charge trapping

摘要

Disclosed is a novel flash memory device using a high-permittivity dielectric such as HfO₂ or TiO₂ as a charge trapping layer. Numerical simulation shows that the novel trapping material will enhance the retention time/programming speed ratio by 5 orders of magnitude, compared to the conventional Si₃N₄ trapping layer. Capacitors with HfO₂ deposited by RTCVD as the charge trap/storage layer in SONOS-type flash memory devices were fabricated and characterized. Compared against devices with Si₃N₄ trapping layer, faster programming speed as well as good retention time is achieved with low programming voltage.