Millisecond Pulsed Light Annealing for Improving Performance of Top-Gate Self-Aligned a-IGZO TFT

The application of millisecond intense pulsed light (IPL) annealing to improve the electrical properties of top-gate self-aligned (TG-SA) amorphous indium gallium zinc oxide (a-IGZO) thin-film transistors (TFTs) was investigated. The IPL annealing with a pulse energy of 40 J/cm<sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><roman>2</roman></sup> and a pulsewidth of 20 ms resulted in 53.7% increase in μ<sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><roman>FE</roman></sub> and a 128.4% improvement in <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">I</i><sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><roman>on</roman></sub>, compared to the unannealed devices. These improvements are attributed to the selective improvement of the specific contact resistivity (ρ<sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><roman>c</roman></sub>) by the IPL annealing. In addition, positive bias stress (PBS) reliability and temperature-dependent <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">I</i>–<italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">V</i> measurements show the improved stability in the IPL-annealed devices and the lower activation energy (<italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">E</i><sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><roman>A</roman></sub>) for charge transport, indicating that the channel region would also have a lower defect density and barrier height for carrier transport.