Probing electron trapping by current collapse in GaN/AlGaN FETs utilizing quantum transport characteristics

TL;DR

This paper investigates how current collapse in GaN/AlGaN FETs affects electron trapping and quantum dot formation, revealing decreased gate capacitance and external control of quantum dots, which impacts device performance.

Contribution

It demonstrates the formation of quantum dots during current collapse in GaN FETs and shows external control over these quantum dots, a novel insight into device behavior.

Findings

Current collapse reduces gate capacitance in GaN FETs.

Quantum dots form during current collapse, affecting electron trapping.

External control of quantum dots is achievable in FET structures.

Abstract

GaN is expected to be a key material for next-generation electronics due to its interesting properties. However, the current collapse poses a challenge to the application of GaN FETs to electronic devices. In this study, we investigate the formation of quantum dots in GaN FETs under the current collapse. By comparing the Coulomb diamond between standard measurements and those under current collapse, we find that the gate capacitance is significantly decreased by the current collapse. This suggests that the current collapse changes the distribution of trapped electrons at the device surface, which is reported in the previous study by operando X-ray spectroscopy. Also, we show external control of quantum dot formation, previously challenging in an FET structure, by using current collapse.