Indium Silicon Oxide TFT Fully Photolithographically Processed for Circuit Integration

• Published in: IEEE journal of the Electron Devices Society Vol. 8; pp. 1162 - 1167
• Main Authors: Yao, Guangyu, Ma, Hanbin, Sambandan, Sanjiv, Robertson, John, Nathan, Arokia
• Format: Journal Article
• Language: English
• Published: New York IEEE 2020; The Institute of Electrical and Electronics Engineers, Inc. (IEEE)
• Subjects: Amorphous semiconductors; Annealing; Bias; Circuits; Energy of dissociation; Free energy; Heat of formation; High impedance; In-Si-O; Indium; Indium oxides; ISO; NBIS; Photoconductivity; Photolithography; Semiconductor devices; Silicon; Silicon dioxide; Silicon oxides; Stability; Stress; Substrates; Temperature measurement; thin film transistor; Thin film transistors; Threshold voltage; threshold voltage shift; Voltage amplifiers
• ISSN: 2168-6734; 2168-6734
• DOI: 10.1109/JEDS.2020.3017392

A new class of amorphous oxide semiconductors based on InO x doped with Ti, W or Si seems to show great promise for large area, flexible, electronics. Of particular interest is the In 2 O 3 :SiO 2 system as it has a relatively large bond dissociation energy, hence highly suited for long-term environmental stability. In this paper, we present a sub-200°C fully photolithographically-processed indium oxide thin film transistor that is fully compatible to circuit integration on plastic substrates. The TFTs typically showed a mobility of 5 cm 2 /Vs, a threshold voltage of −0.16 V and a subthreshold swing of 312 mV/dec. We report on its stability behavior when subject to electrical bias stress and negative bias illumination stress, along with a pulse-based compensation solution for persistent photoconductivity arising from the latter. Following static characterization and subsequent parameter extraction of the indium silicon oxide TFT, design considerations are presented along with measurement results of a fully integrated TFT voltage amplifier with high impedance subthreshold loading.