Impact of 2D-Graphene on SiN Passivated AlGaN/GaN MIS-HEMTs under Mist Exposure

TL;DR

This study demonstrates that adding a 2D graphene layer enhances moisture resistance in AlGaN/GaN MIS-HEMTs, maintaining electrical performance under mist exposure better than devices without graphene.

Contribution

It provides systematic analysis showing the graphene layer significantly improves moisture resistance and device stability under mist exposure compared to traditional passivation.

Findings

Devices without graphene show up to 23% decrease in drain current density.

Graphene layer maintains stable electrical characteristics under mist exposure.

Graphene enhances moisture resistance of SiN passivation layer.

Abstract

The effect of a two dimensional (2D) graphene layer (GL) on top of the silicon nitride (SiN) passivation layer of AlGaN/GaN metal-insulator-semiconductor high-electron-mobility transistors (MIS-HEMTs) has been systematically analyzed. Results showed that in the devices without the GL, the maximum drain current density (I_D,max) and the maximum transconductance (g_m,max) decreased gradually as the mist exposure time increased, up to 23% and 10%, respectively. Moreover, the gate lag ratio (GLR) increased around 10% during mist exposure. In contrast, devices with a GL showed a robust behavior and not significant changes in the electrical characteristics in both DC and pulsed conditions. The origin of these behaviors has been discussed and the results pointed to the GL as the key factor for improving the moisture resistance of the SiN passivation layer.