High mobility thin-film transistor with solution-processed hafnium-oxide dielectric and zinc-indium-tin-oxide semiconductor

作者：Zhu Le-Yong; Gao Ya-Na; Zhang Jian-Hua; Li Xi-Feng^*

来源：Acta Physica Sinica, 2015, 64(16): 168501.

DOI：10.7498/aps.64.168501

• thin film transistor
• hafnium oxide
• zinc indium tin oxide
• high mobility

In this paper, bottom-gate-top-contact structured thin-film transistors (TFTs) are fabricated by solution-processing of hafnium oxide (HfO2) dielectrics and zinc-indium-tin-oxide (ZITO) semiconductors. Solution-processed HfO2 films are annealed at different temperatures, and the 500 degrees C annealed HfO2 dielectrics can exhibit optimizing film properties such as smooth surfaces (the RMS value of HfO2 films is less than 1 nm), low leakage current density (1.25 x 10(-7) A/cm(2) at 1 MV/cm), high transmittance (above 80% at the wavelength ranging from 400 to 800 nm) and high relative dielectric constant (about 12). The smooth surface of HfO2 dielectrics is attributed to the decreased charge trapping states at the interface between the HfO2 dielectrics and ZITO semiconductors, and thus improves the device electrical performance and stability. Hence, TFT devices of HfO2 dielectrics annealed at 500 degrees C show a high saturated field effect mobility of more than 100 cm(2).V-1.s(-1) a low threshold voltage of -0.5 V, an on-to-off current ratio of 5x10(6) and a small subthreshold swing of 105 mV/dec. An almost negligible threshold voltage shift is observed under a positive bias stress for 1000 s, indicating the excellent stability of HfO2 TFT devices.

• 出版日期2015-8-20
• 单位上海大学