High Baliga’s Figure of Merit Amorphous InGaZnO Power Transistor With Ultra-Thin Indium Zinc Oxide Buried Layer

In this work, we fabricated high-voltage (HV) amorphous InGaZnO (a-IGZO) thin film transistors (TFTs) consisting of an ultra-thin buried layer of amorphous InZnO (a-IZO) and a drain offset region. With a drain offset length ( ${L}_{\text {offset}}{)}$ of $2 \mu \text{m}$ , a breakdown voltage ( ${V}_{\text {BD}}{)}$ of 457 V is achieved. The output current is four times higher than the conventional device, thanks to the a-IZO buried layer. TCAD simulation is performed to reveal the operating mechanism of the fabricated device. A sub-channel is formed at the a-IZO/a-IGZO interface to improve the current capability of the HV device, achieving an excellent specific on- resistance ( ${R}_{\text {on,sp}}$ ) of ${6}.{25}\times {10} ^{{3}}\,\,\text{m}\Omega \cdot $ cm2 and a Baliga’s Figure of Merit (BFOM) of 33.4 KW/cm2.