• Bhalerao, Sagar
• Berger, Paul R.
• Lupo, Donald

Abstract

Transparent electronics based upon metal oxide semiconductors is a major rapidly growing and promising technology for thin film electronics, especially printed electronics. The oxide semiconductors, especially the amorphous metal ones, made a remarkable progress in a relatively short time, challenging silicon not only in conventional applications but opening doors to completely new and disruptive areas like flexible and printed electronics. The special emphasis of metal oxide semiconductors, due to the high carrier mobilities, wide band gaps, broad transparency windows, tunable doping levels, and amenability to room-temperature film growth. Among metal oxides, In2O3 is a promising n-type semiconductor having a wide band gap (3.6-3.75 eV), high mobility [1]. Here we report the thin film transistor (TFT) fabrication by solution processable high-quality In2O3 thin films and anodic oxidized Al2O3 to form a dielectric.<br/>TFTs with an indium oxide based semiconductors channel provides the added advantage of allowing for very low temperature processing. Oxide semiconductor based devices is a new technology that not only may replace the conventional silicon technology in some applications but also opens new areas of applications, probably faster than we can imagine or realize. Here we unite the device design, fabrication using very thin anodic Al2O3 dielectric testing to push the boundaries of lower temperature fabrication to reduce operating voltage, less than 5 volts. The TFT tested here exhibit field-effect mobilities as high as µsat = 3.5 cm2/V-1s-1, Ion/Ioff 105, turn on voltage 0.6 V and operate at 3.0 V.<br/>The indium oxide TFTs were fabricated on glass substrates, with a bottom-gate top-contact TFTs were prepared on glass substrate. Initially, to form a gate contact 100 µm Al metal evaporated with a shadow mask, using a e-beam evaporator. The anodization process has been performed to form a good quality, pin hole free and room temperature aluminum oxide dielectric films [2,3]. Depending on the conditions of preparation the dielectric constant of the aluminum oxide varies between 7.5 to as high as 15 [4]. The anodic aluminum shows an excellent dielectric property along with very dense barrier oxide films that can be grown on the substrates at room temperature [5]. Followed by a spin coating of indium oxide film [6], the samples were dried at 90°C on a hot plate in air for 15 min. and then annealed at 300 °C for 30 min. Finally, to 100 um Aluminum were evaporated by using a shadow mask to form a drain – source contact. Electrical characterization was performed in using a keysight B1500A semiconductor device parameter analyzer.<br/>

Topics

• impedance spectroscopy
• amorphous
• mobility
• thin film
• aluminum oxide
• aluminium
• dielectric constant
• glass
• glass
• laser emission spectroscopy
• Silicon
• Indium
• spin coating
• n-type semiconductor