For high-electron-mobility transistors based on two-dimensional electron gas (2DEG) within a quantum well, such as those based on AlGaN/GaN heterostructure, a Schottky-gate is used to maximize the amount of charge that can be induced and thereby the current that can be achieved. However, the Schottky-gate also leads to very high leakage current through the gate electrode. Adding a conventional dielectric layer between the nitride layers and gate metal can reduce leakage; but this comes at the price of a reduced drain current. Here, we used a ferroic HfO2-ZrO2 bilayer as the gate dielectric and achieved a simultaneous increase in the ON current and decrease in the leakage current, a combination otherwise not attainable with conventional dielectrics. This approach surpasses the conventional limits of Schottky GaN transistors and provides a new pathway to improve performance in transistors based on 2DEG.
@article{arxiv.2506.16758,
title = {Negative capacitance overcomes Schottky-gate limits in GaN high-electron-mobility transistors},
author = {Asir Intisar Khan and Jeong-Kyu Kim and Urmita Sikder and Koushik Das and Thomas Rodriguez and Rohith Soman and Srabanti Chowdhury and Sayeef Salahuddin},
journal= {arXiv preprint arXiv:2506.16758},
year = {2025}
}