Integration of p-type Cr2O3 on Ultra-Wide Bandgap AlGaN PolFETs with 2.5 kV Breakdown Voltage
Abstract
We demonstrate UWBG AlGaN polarization-graded field-effect transistors (PolFETs) incorporating room-temperature sputtered p-type oxide Cr2O3 as a P-N heterojunction gate, enabling superior field management for lateral device breakdown compared to conventional Schottky gates. Devices using reverse-graded n-AlGaN contact layers achieved a record-low Rc of 0.56 Ω-mm. The Cr2O3 gate exhibits a turn-on voltage VON > 3.5 V and a positive threshold voltage shift of +1.63 V relative to Schottky gates, displaying enhanced channel depletion from the P-N junction. Fabricated devices show high Imax (590 mA/mm) and ION/IOFF of 3x10^7. Devices exhibited state-of-the-art VBR > 2.5 kV with 11.2 mΩ-cm^2 specific on-resistance (LGD = 9.55 um, average breakdown field > 2.5 MV/cm), while shorter gate-drain devices showed high breakdown fields up to 5.3 MV/cm with 0.28 mΩ-cm^2 specific on-resistance. These results showcase sputtered p-Cr2O3 as a viable, low thermal budget P-N junction gate technology for high-Al-composition AlGaN transistors in RF and power electronics.
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BibTeX
@misc{pratt2026integration,
title = {{Integration of p-type Cr2O3 on Ultra-Wide Bandgap AlGaN PolFETs with 2.5 kV Breakdown Voltage}},
author = {Jonathan Pratt and Yizheng Liu and Ijaas Mohamed and Seungheon Shin and Akilesh Srikanth and Md Saklain Morshed and Brianna A. Klein and Andrew Armstrong and Andrew A. Allerman and Sriram Krishnamoorthy and Siddharth Rajan},
howpublished = {arXiv},
year = {2026},
month = sep,
doi = {10.48550/arxiv.2609.29990},
eprint = {2609.29990},
archivePrefix = {arXiv},
url = {https://arxiv.org/abs/2609.29990},
note = {CC BY 4.0},
}
RIS
TY - UNPB
TI - Integration of p-type Cr2O3 on Ultra-Wide Bandgap AlGaN PolFETs with 2.5 kV Breakdown Voltage
AU - Jonathan Pratt
AU - Yizheng Liu
AU - Ijaas Mohamed
AU - Seungheon Shin
AU - Akilesh Srikanth
AU - Md Saklain Morshed
AU - Brianna A. Klein
AU - Andrew Armstrong
AU - Andrew A. Allerman
AU - Sriram Krishnamoorthy
AU - Siddharth Rajan
PY - 2026
DA - 2026/09/24
PB - arXiv
DO - 10.48550/arxiv.2609.29990
UR - https://arxiv.org/abs/2609.29990
AB - We demonstrate UWBG AlGaN polarization-graded field-effect transistors (PolFETs) incorporating room-temperature sputtered p-type oxide Cr2O3 as a P-N heterojunction gate, enabling superior field management for lateral device breakdown compared to conventional Schottky gates. Devices using reverse-graded n-AlGaN contact layers achieved a record-low Rc of 0.56 Ω-mm. The Cr2O3 gate exhibits a turn-on voltage VON > 3.5 V and a positive threshold voltage shift of +1.63 V relative to Schottky gates, displaying enhanced channel depletion from the P-N junction. Fabricated devices show high Imax (590 mA/mm) and ION/IOFF of 3x10^7. Devices exhibited state-of-the-art VBR > 2.5 kV with 11.2 mΩ-cm^2 specific on-resistance (LGD = 9.55 um, average breakdown field > 2.5 MV/cm), while shorter gate-drain devices showed high breakdown fields up to 5.3 MV/cm with 0.28 mΩ-cm^2 specific on-resistance. These results showcase sputtered p-Cr2O3 as a viable, low thermal budget P-N junction gate technology for high-Al-composition AlGaN transistors in RF and power electronics.
ER -