Polar ZnO thin-film nonvolatile transistors with (Bi, Nd)4Ti3O12 gate insulators
Key Laboratory of Low Dimensional Materials and Application Technology of Ministry of Education, Xiangtan University - Hunan Xiangtan 411105, China Faculty of Materials, Optoelectronics and Physics, Xiangtan University - Hunan Xiangtan 411105, China
Accepted: 8 February 2012
Polar ZnO thin-film transistors (TFTs) with (Bi,Nd)4Ti3O12 (BNT) as well as SiO2 gate insulators were fabricated. The polarization-voltage (P-V) hystersis loops of ZnO/BNT and BNT films and the electrical properties of prepared TFTs were investigated. The P-V loop of a ZnO/BNT film shows obvious asymmetrical widening. The threshold voltage, channel mobility, and on/off ratio of ZnO/BNT TFTs reach to 1.3 V, 3.5 cm2 V−1 s−1, and 8×107, respectively. Notably, the device shows a nearly unchanged memory window of about 3.9 V after a 24 h retention test and a large drain-current on/off ratio of about 107 after a 24 h data retention test. These can be mainly attributed to the polarization interaction and the relatively good interface properties between a ZnO film and a BNT film. These results suggest that the ZnO/BNT TFTs are suitable for nonvolatile digital circuits on a flat panel display system.
PACS: 73.61.Ga – II-VI semiconductors / 73.40.Qv – Metal-insulator-semiconductor structures (including semiconductor-to-insulator) / 77.55.hf – ZnO
© EPLA, 2012