TFT LC Oscillators on Glass and Plastic for W ireless Functions in Large-Area Fle x ible Electronic Systems

High-frequency signals have important applications in large-area hybrid systems, enabling efficient wireless transmission of power and information. We report zinc-oxide thin-film transistor (ZnO TFT) cross-coupled LC oscillator circuits on glass and 3.5-μm-thick polyimide substrates that achieve oscillation frequencies as high as 35 MHz and 17 MHz, respectively. The TFTs are designed for high unity power-gain frequency fMAX by minimizing gate resistance and device capacitances. In a resonant oscillator topology, this enables oscillation well above the cutoff frequency fT of the TFTs. Oscillators on plastic benefit from the improved dimensional stability of spin-cast ultrathin substrates, which allows TFTs on these substrates to have gate resistances and device capacitances comparable to TFTs on glass. Author