Fabrication and Operating Mechanism of Deep-UV Transparent Semiconducting SrSnO3-based Thin Film Transistor

Thin film transistor (TFT) with deep-UV transparency is a promising component for the next generation optoelectronics such as biosensor. Among several deep-UV transparent oxide semiconductors, SrSnO
₃
is an excellent candidate material owing to its wide bandgap (~4.6 eV) and rather high carrier electron mobility. Here we show fabrication and operating mechanism of the SrSnO
₃
-based TFT. We fabricated metal-insulator-semiconductor TFT structure on the 28-nm-thick SrSnO
₃
film. The resultant TFT showed clear transistor characteristics; the on-to-off current ratio was ~10
²
, the threshold voltage was ~ --18 V, and the field effect mobility was ~14 cm
²
V
^-1
s
^-1
. The effective thickness of the electron channel gradually increased with gate voltage and saturated at ~5 nm, which was evaluated by the thermopower modulation.