Metal-Semiconductor Field-Effect Transistors With In–Ga–Zn–O Channel Grown by Nonvacuum-Processed Mist Chemical Vapor Deposition

In-Ga-Zn-O (IGZO) thin films (TFs) were grown by cost-effective nonvacuum solution-processed mist chemical vapor deposition. High quality AgO_x Schottky contacts (SCs) were fabricated on these IGZO TFs with rectification ratios and barrier heights as high as 7.9 × 10⁷ and 1 eV, respectively, combined with ideality factors as low as 1.32. These SCs were subsequently used as gate contacts in the production of metal-semiconductor field-effect transistors (MESFETs) with excellent switching and stability characteristics. For example, typical (W/L 785 μm/5 μm) MESFETs were capable of providing ON-currents up to 245 μA, combined with a large ON/OFF ratio of 3.8 × 10⁷. A mobility of 3.2 cm²/(V.s) and a low subthreshold swing of 356 mV/decade were achieved in the W/L 524 μm/10 μm transistors. Under positive bias stress, these MESFETs were highly stable, demonstrating the feasibility of using a combination of mist chemical vapor deposition grown IGZO and AgO_x SCs to produce stable, low power consumption, and low-cost switching devices.