Carbon-nanotube-based nonvolatile memory with oxide-nitride-oxide film and nanoscale channel

We have fabricated a single-wall carbon-nanotube (CNT)-based nonvolatile memory device using SiO2-Si3N4-SiO2 (ONO) layers as a storage node. The memory device is composed of a top gate structure with a channel width of a few nanometers and the ONO layer embedded between CNT and gate electrode. When the bias voltage between the CNT and gate electrode increases to 4 V, charges are tunneled out from CNT surfaces and captured to the traps in the ONO layers. Stored charges on the trap sites make the threshold voltage shift of 60 mV and is independent of charging time, suggesting that the ONO has traps with a quasiquantized energy state. The quantized state is related to the localized high electric field associated with CNT channel. The CNT-field-effect transistor with an ONO storage node could be used for an ultrahigh-density nonvolatile memory. (C) 2003 American Institute of Physics.