Investigation of Isolation Approaches and the Stoichiometry of SiNx Passivation Layers in “Buffer-Free” AlGaN/GaN Metal–Insulator–Semiconductor High-Electron-Mobility Transistors
Journal article, 2023

Critical process modules for the fabrication of metal–insulator–semiconductor high-electron-mobility transistors (MISHEMTs) based on a novel ‘buffer-free’ AlGaN/GaN heterostructure grown with metal–organic chemical vapor deposition (MOCVD) are presented. The methods of isolation and passivation for this type of heterostructure are investigated. Utilizing nitrogen implantation, it is possible to achieve off-state destructive breakdown voltages (BVs) of 2496 V for gate–drain distances up to 25 μm, whereas mesa isolation techniques limit the BV below 1284 V. The stoichiometry of the SiNx passivation layer displays a small impact on the static and dynamic on-resistance. However, MISHEMTs with Si-rich passivation show off-state gate currents in the range of 1–100 μA mm−1 at voltages above 1000 V, which is reduced below 10 nA mm−1 using a stoichiometric SiNx passivation layer. Destructive BVs of 1532 and 1742 V can be achieved using gate-integrated and source-connected field plates for MIHEMTs with stoichiometric and Si–rich passivation layers, respectively. By decreasing the field plate lengths, it is possible to achieve BVs of 2200 V. This demonstrates the implementation of MISHEMTs with high-voltage operation and low leakage currents on a novel “buffer-free” heterostructure by optimizing the SiNx stoichiometry.

mesa isolations

SiN passivations x

high voltages

AlGaN/GaN

nitrogen implantation

buffer free

metal–insulator–semiconductor high-electron-mobility transistors

Author

Björn Hult

Chalmers, Microtechnology and Nanoscience (MC2), Microwave Electronics

Mattias Thorsell

Chalmers, Microtechnology and Nanoscience (MC2), Microwave Electronics

J. T. Chen

SweGaN AB

Niklas Rorsman

Chalmers, Microtechnology and Nanoscience (MC2), Microwave Electronics

Physica Status Solidi (A) Applications and Materials Science

1862-6300 (ISSN) 1862-6319 (eISSN)

Vol. 220 8 2200533

Subject Categories

Other Physics Topics

Other Electrical Engineering, Electronic Engineering, Information Engineering

Condensed Matter Physics

DOI

10.1002/pssa.202200533

More information

Latest update

7/7/2023 5