Overcoming Negative nFET VTH by Defect-Compensated Low-Thermal Budget ITO-IGZO Hetero-Oxide Channel to Achieve Record Mobility and Enhancement-mode Operation
July 24, 2023
Publication
- Overcoming Negative nFET VTH by Defect-Compensated Low-Thermal Budget ITO-IGZO Hetero-Oxide Channel to Achieve Record Mobility and Enhancement-mode Operation
- July 24, 2023
We have successfully demonstrated, low-thermal budget oxide-based FETs with a record I D,max of 790μA/μm at V DS = 1V, an enhancement-mode operation (V DH >0), S.S. <90 mV/dec., and DIBL ~20mV/V at an ultra-scaled channel length LCH CH of 50 nm. This is enabled by an optimized InSnO x -InGaZnO x hetero-junction channel to achieve channel defect self-compensation [1]. This approach overcomes the fundamental issue of negative VTH seen in n-type oxide FETs due to donor-type channel oxygen vacancy (Vo) and the limited tunability of gate metal work function. Through our ITO-IGZO channel and defect self-compensation approach, our transistor effective mobility (μeff) is boosted to 110 cm2/V⋅s with the channel thickness (TCH) scaled down to 4 nm. This unique T CH -independent mobility behavior is not observed for IGZO or ITO mono-channel FETs. With such enhancement, our ITO-IGZO FETs exhibit the best-in-class mobility among oxide-based FETs, and are competitive to unstrained Silicon thin film and SOI FETs, while being compatible with sub- 400 °C back-end-of-line (BEOL) processes.
Researcher/Author: Sonu Hooda, Chun-Kuei Chen, Manohar Lal, Shih-Hao Tsai
, Evgeny Zamburg , Aaron Voon-Yew Thean
Published in: IEEE
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https://ieeexplore.ieee.org/document/10185266