Evaluation of Thermal Versus Plasma-Assisted ALD Al2O3 as Passivation for InAlN/AlN/GaN HEMTs
Journal article, 2015

Al2O3 films deposited by thermal and plasma-assisted atomic layer deposition (ALD) were evaluated as passivation layers for InAlN/AlN/GaN HEMTs. As a reference, a comparison was made with the more conventional plasma enhanced chemical vapor deposition deposited SiNx passivation. The difference in sheet charge density, threshold voltage, f(T) and f(max) was moderate for the three samples. The gate leakage current differed by several orders of magnitude, in favor of Al2O3 passivation, regardless of the deposition method. Severe current slump was measured for the HEMT passivated by thermal ALD, whereas near-dispersion free operation was observed for the HEMT passivated by plasma-assisted ALD. This had a direct impact on the microwave output power. Large-signal measurements at 3 GHz revealed that HEMTs with Al2O3 passivation exhibited 77% higher output power using plasma-assisted ALD compared with thermal ALD.

Al2O3

GaN HEMT

InAlN

passivation

ALD

Author

Anna Malmros

Chalmers, Microtechnology and Nanoscience (MC2), Microwave Electronics

P. Gamarra

Thales Group

M. A. di Forte-Poisson

Thales Group

Hans Hjelmgren

Chalmers, Microtechnology and Nanoscience (MC2), Microwave Electronics

C. Lacam

Thales Group

Mattias Thorsell

Chalmers, Microtechnology and Nanoscience (MC2), Microwave Electronics

M. Tordjman

Thales Group

R. Aubry

Thales Group

Niklas Rorsman

Chalmers, Microtechnology and Nanoscience (MC2), Microwave Electronics

IEEE Electron Device Letters

0741-3106 (ISSN)

Vol. 36 3 235-237

Areas of Advance

Nanoscience and Nanotechnology (2010-2017)

Subject Categories

Other Electrical Engineering, Electronic Engineering, Information Engineering

Condensed Matter Physics

DOI

10.1109/LED.2015.2394455

More information

Latest update

3/25/2020