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

Abstract

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 ( <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">${L}_{\text {offset}}{)}$ </tex-math></inline-formula> of <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$2 \mu \text{m}$ </tex-math></inline-formula> , a breakdown voltage ( <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">${V}_{\text {BD}}{)}$ </tex-math></inline-formula> 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 ( <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">${R}_{\text {on,sp}}$ </tex-math></inline-formula> ) of <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">${6}.{25}\times {10} ^{{3}}\,\,\text{m}\Omega \cdot $ </tex-math></inline-formula> cm2 and a Baliga’s Figure of Merit (BFOM) of 33.4 KW/cm2.