Demonstration of AlGaN/GaN MISHEMT on Si with Low-Temperature Epitaxy Grown AlN Dielectric Gate

Matthew Whiteside,Abhinay Sandupatla,Yilmaz Dikme,Subramaniam Arulkumaran,Geok Ing Ng

doi:10.3390/electronics9111858

Matthew Whiteside, Abhinay Sandupatla + Show 3 more

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https://doi.org/10.3390/electronics9111858

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Journal: Electronics	Publication Date: Nov 5, 2020
Citations: 6	License type: CC BY 4.0

Affiliation: Nanyang Technological University, Aixtron (Germany)

Abstract

AlGaN/GaN metal-insulator-semiconductor high-electron-mobility transistors (MISHEMT) with a low-temperature epitaxy (LTE)-grown single crystalline AlN gate dielectric were demonstrated for the first time and the post-gate annealing effects at 400 °C were studied. The as-deposited LTE-AlN MISHEMT showed a maximum drain current (IDmax) of 708 mA/mm at a gate bias of 4 V and a maximum extrinsic transconductance (gmmax) of 129 mS/mm. The 400 °C annealed MISHEMT exhibited an increase of 15% in gmmax, an order of magnitude reduction in reverse gate leakage and about a 3% suppression of drain current (ID) collapse. The increase of gmmax by post-gate annealing is consistent with the increase of 2DEG mobility. The suppression of ID collapse and the reduction of gate leakage current is attributed to the reduction of interface state density (5.0 × 1011 cm−2eV−1) between the AlN/GaN interface after post-gate annealing at 400 °C. This study demonstrates that LTE grown AlN is a promising alternate material as gate dielectric for GaN-based MISHEMT application.

Highlights

AlGaN/GaN based high-electron-mobility transistors (HEMTs) have demonstrated excellent high-frequency and high-power performance owing to their excellent material properties, such as large breakdown field, wide band gap and high electron mobility [1,2,3,4]
We have recently reported the properties of interface states for AlGaN/GaN metal-insulator-semiconductor diodes (MIS-diodes) using the low-temperature epitaxy (LTE) grown AlN [21,22] So far, no reports have discussed the AlGaN/GaN metal-insulator-semiconductor high-electron-mobility transistors (MISHEMT) with
The improvement in Igleak is attributed to the improvement of interface properties of LTE-AlN on GaN/AlGaN after the 400 ◦ C annealing

Summary

Introduction

AlGaN/GaN based high-electron-mobility transistors (HEMTs) have demonstrated excellent high-frequency and high-power performance owing to their excellent material properties, such as large breakdown field, wide band gap and high electron mobility [1,2,3,4]. The high gate-leakage occurs due to the Schottky metal contact, while current collapse is caused by charge trapping at the surface states present on the AlGaN surface. To solve these issues, various materials such as Al2 O3 [6,7], HfO2 [8] or ZrO2 [9] have been used as both a passivation layer and gate dielectrics. There are two main methods used for the deposition of AlN namely metal-organic chemical vapor deposition [14] (MOCVD) and plasma-enhanced atomic layer deposition [15,16]

Methods

Results

Conclusion