Low Subthreshold Slope AlGaN/GaN MOS-HEMT with Spike-Annealed HfO2 Gate Dielectric

Min Jae Yeom; Jeong Yong Yang; Chan Ho Lee; Junseok Heo; Roy Byung Kyu Chung; Geonwook Yoo

doi:10.3390/mi12121441

Low Subthreshold Slope AlGaN/GaN MOS-HEMT with Spike-Annealed HfO₂ Gate Dielectric

Micromachines (Basel). 2021 Nov 25;12(12):1441. doi: 10.3390/mi12121441.

Authors

Min Jae Yeom¹, Jeong Yong Yang¹, Chan Ho Lee¹, Junseok Heo², Roy Byung Kyu Chung³, Geonwook Yoo¹

Affiliations

¹ School of Electronic Engineering, Soongsil University, Seoul 06938, Korea.
² Department of Electrical and Computer Engineering, Ajou University, Suwon 16499, Korea.
³ Department of Electronic Materials Science and Engineering, Kyungpook National University, Daegu 41566, Korea.

Abstract

AlGaN/GaN metal-oxide semiconductor high electron mobility transistors (MOS-HEMTs) with undoped ferroelectric HfO₂ have been investigated. Annealing is often a critical step for improving the quality of as-deposited amorphous gate oxides. Thermal treatment of HfO₂ gate dielectric, however, is known to degrade the oxide/nitride interface due to the formation of Ga-containing oxide. In this work, the undoped HfO₂ gate dielectric was spike-annealed at 600 °C after the film was deposited by atomic layer deposition to improve the ferroelectricity without degrading the interface. As a result, the subthreshold slope of AlGaN/GaN MOS-HEMTs close to 60 mV/dec and on/off ratio>10⁹ were achieved. These results suggest optimizing the HfO₂/nitride interface can be a critical step towards a low-loss high-power switching device.

Keywords: ALD HfO2; MOS-HEMT; Spike annealing; ferroelectric.

Abstract

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