Low‐Voltage Heterojunction Metal Oxide Transistors via Rapid Photonic Processing

Abstract

Solution‐processed metal oxide thin‐film transistors (TFTs) represent a promising technology for applications in existing but also emerging large‐area electronics. However, high process temperatures and lengthy annealing times represent two remaining technical challenges. Different approaches aiming to address these challenges have been proposed but progress remains modest. Here, the development of high electron mobility metal oxide TFTs based on photonically converted Al2O3/ZrO2 and In2O3/ZnO bilayers acting as the high‐k dielectric and electron‐transporting channel, respectively is described. Sequential solution‐phase deposition and photonic processing lead to low substrate temperature (<200 °C) while minimizing the overall process time to less than 60 s without compromising the quality of the formed layers. The bilayer Al2O3/ZrO2 dielectric exhibits low leakage current density (10−6 A cm−2 at 1 MV cm−1), high geometric capacitance (≈120 nF cm−2) and breakdown electric field of ≈1 MV cm−1. Combining Al2O3/ZrO2 with a photonically converted In2O3/ZnO heterojunction channels, results in TFTs with high electron mobility (19 cm2 V−1 s−1), low operation voltage (≤2 V), high current on/off ratio (>106), and low subthreshold swing (108 mV dec−1), that can be manufactured even onto thermally sensitive polymer substrates. The work is a significant step toward all‐photonic processed metal oxide electronics.

Recent Advances in Metal-Oxide Thin-Film Transistors: Flexible/Stretchable Devices, Integrated Circuits, Biosensors, and Neuromorphic Applications

“…Synthesis methods of metal-oxide semiconductors are divided into a vacuum-based process including sputtering method, thermal evaporation method, and atomic layer deposition (ALD) method (Figure 1a-c) [22][23][24] and solution-based process (Figure 1d-g) [25][26][27][28]. The sputtering method uses plasma to separate material from a target surface and the material particles are deposited on a substrate [29].…”

High‐Performance Coplanar Dual‐Channel a‐InGaZnO/a‐InZnO Semiconductor Thin‐Film Transistors with High Field‐Effect Mobility

“…[ 38 ] Besides, a‐IZO/a‐IGZO/GI TFT exhibits the V Th close to 0 V and to support the electron confinement effect similar to 2DEG formation. [ 34,37,38 ] The formation and distribution of the 2DEG system in coplanar dual‐channel TFTs need further investigation. Accounting for the advantage of ∆ E C on surface band bending, dual‐channel conduction takes place in a‐IZO/a‐IGZO/GI TFT with considerably large carrier transport separated by the ∆ E C barrier which might also help to avoid carrier scattering with large I D , excellent μ FE of 49.5 cm 2 V −1 s −1 , and reduced I OFF of ≈10 –13 A under V DS = 1.0 V in our dual‐channel MOS TFTs.…”

“…Recent studies on heterojunction TFTs also demonstrate 2D electron gas (2DEG) system at heterointerface because of large conduction band offset (∆ E C ) between semiconducting layers. [ 30–37 ] Such a 2DEG system helps to achieve remarkable large mobility, however, the negative V Th is evident. [ 34,37 ] Koretomo et al.…”

“…[ 30–37 ] Such a 2DEG system helps to achieve remarkable large mobility, however, the negative V Th is evident. [ 34,37 ] Koretomo et al. also studied the quantum confinement effect in a‐InGaZnO heterojunction TFT to explain twofold increased mobility.…”

Memristive Devices with Multiple Resistance States Based on the Migration of Protons in α‐MoO3/SrCoO2.5 Stacks

“…Designing functional materials through tunable ionic evolution has inspired many novel oxide‐based electronics, photonic, magnetoelectric and spintronic devices. [ 1–6 ] Especially, electron doping‐driven phase transition accompanied by resistance changes has found its way in developing nonvolatile memory electronics for neuromorphic applications. [ 7–10 ] The electron doping is generally accomplished by the introduction of reducing chemical species, such as protons or metal cations with small ionic radii, like Li + and Na + .…”