Full-Swing a-IGZO Inverter With a Depletion Load Using Negative Bias Instability Under Light Illumination

A high-performance amorphous indium-gallium-zinc-oxide thin-film transistor (TFT) inverter, which is composed of an enhancement mode driver and a depletion mode load, is implemented by selectively inducing the negative bias illumination temperature stress (NBITS) to the load TFT. Under NBITS, the transfer curve of the load TFT shows a parallel shift into the negative bias direction without a significant change in the subthreshold slope and recovers very slowly after terminating the NBITS even under harsh bias and temperature stress conditions. The proposed inverter shows much improved switching characteristics including higher voltage gain, wider swing range, and higher noise margins compared to the conventional inverter with an enhancement load.