Characteristics of low-temperature annealed ZnO-TFTs
- We investigated the effects of low-temperature annealing at 300 캜 and 500 캜 in air and N2 on the electrical characteristics of ZnO thin-film transistors (TFTs). The ZnO layers were deposited on a bottom-gate patterned Si substrate by radio-frequency (RF) sputtering at room temperature. A low-temperature oxide (LTO) served as the gate dielectric. Unannealed ZnO-TFTs were operated in enhancement mode with a threshold voltage of 13.7 V. A field-effect mobility of 0.024 cm2/Vs and an on뻩ff current ratio of 2 ?102 were obtained. Low-temperature annealing of the ZnO-TFTs in an N2 atmosphere reduced the threshold voltage of the TFTs to 12.5 V, and increased the field-effect mobility to 0.047 cm2/Vs and the on뻩ff current ratio to 2 ?103.
- Keywords: Zinc oxide, Thin-film transistor, RF sputtering, Bottom gate, Annealing