PUB-2013-RMI

Record Mobility in Fully Transparent p-type Tin Monoxide Films and Devices Processed by Phase Engineering

J.A. Caraveo, P. Nayak, D. Granato, U. Schwingenschlogl, and H.N. Alshareef, “Record Mobility in Fully Transparent p-type Tin Monoxide Films and Devices Processed by Phase Engineering”
ACS Nano, 20137 (6), pp 5160–5167
J.A. Caraveo, P. Nayak, D. Granato, U. Schwingenschlogl, and H.N. Alshareef
p-type oxide; tin monoxide; thin-film transistors
2013
Here, we report the fabrication of nanoscale (15 nm) fully transparent p-type SnO thin film transistors (TFT) at temperatures as low as 180 °C with record device performance. Specifically, by carefully controlling the process conditions, we have developed SnO thin films with a Hall mobility of 18.71 cm2 V–1 s–1 and fabricated TFT devices with a linear field-effect mobility of 6.75 cm2 V–1 s–1 and 5.87 cm2 V–1 s–1 on transparent rigid and translucent flexible substrates, respectively. These values of mobility are the highest reported to date for any p-type oxide processed at this low temperature. We further demonstrate that this high mobility is realized by careful phase engineering. Specifically, we show that phase-pure SnO is not necessarily the highest mobility phase; instead, well-controlled amounts of residual metallic tin are shown to substantially increase the hole mobility. A detailed phase stability map for physical vapor deposition of nanoscale SnO is constructed for the first time for this p-type oxide.