Gigahertz Zinc-Oxide TFT-Based Oscillators

A number of papers have been published over the past few years demonstrating metal-oxide thin-film-transistors (TFTs) with $f_{T}\ \mathrm{and}/\mathrm{or}\ f_{MAX}$ over 1GHz [1]–[4]. However, these works have focused purely on device-level characterization and have not demonstrated gigahertz circuit operation. In this work, we demonstrate a large-area-compatible metal-oxide TFT-based cross-coupled LC oscillator operating at 1.25GHz, processed at flex-compatible temperatures $( . Achieving this required co-optimization of TFT and inductor dimensions/layouts, balancing device performance with parasitics (resistances, capacitances).