Highly
Uniform Resistive Switching Performances Using
Two-Dimensional Electron Gas at a Thin-Film Heterostructure for Conductive
Bridge Random Access Memory
posted on 2019-08-06, 18:36authored bySung Min Kim, Hye Ju Kim, Hae Jun Jung, Seong Hwan Kim, Ji-Yong Park, Tae Jun Seok, Tae Joo Park, Sang Woon Lee
This
research demonstrates, for the first time, the development
of highly uniform resistive switching devices with self-compliance
current for conductive bridge random access memory using two-dimensional
electron gas (2DEG) at the interface of an Al2O3/TiO2 thin-film heterostructure via atomic layer deposition
(ALD). The cell is composed of Cu/Ti/Al2O3/TiO2, where Cu/Ti and Al2O3 overlayers are
used as the active/buffer metals and solid electrolyte, respectively,
and the 2DEG at the interface of Al2O3/TiO2 heterostructure, grown by the ALD process, is adopted as
a bottom electrode. The Cu/Ti/Al2O3/TiO2 device shows reliable resistive switching characteristics
with excellent uniformity under a repetitive voltage sweep (direct
current sweep). Furthermore, it exhibits a cycle endurance over 107 cycles under short pulse switching. Remarkably, a reliable
operation of multilevel data writing is realized up to 107 cycles. The data retention time is longer than 106 s
at 85 °C. The uniform resistance switching characteristics are
achieved via the formation of small (∼a few nm width) Cu filament
with a short tunnel gap (<0.5 nm) owing to the 2DEG at the Al2O3/TiO2 interface. The performance and
operation scheme of this device may be appropriate in neuromorphic
applications.