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Title: Impact of annealing temperature on the mechanical and electrical properties of sputtered aluminum nitride thin films

Aluminium nitride (AlN) is a promising material for challenging sensor applications such as process monitoring in harsh environments (e.g., turbine exhaust), due to its piezoelectric properties, its high temperature stability and good thermal match to silicon. Basically, the operational temperature of piezoelectric materials is limited by the increase of the leakage current as well as by enhanced diffusion effects in the material at elevated temperatures. This work focuses on the characterization of aluminum nitride thin films after post deposition annealings up to temperatures of 1000 °C in harsh environments. For this purpose, thin film samples were temperature loaded for 2 h in pure nitrogen and oxygen gas atmospheres and characterized with respect to the film stress and the leakage current behaviour. The X-ray diffraction results show that AlN thin films are chemically stable in oxygen atmospheres for 2 h at annealing temperatures of up to 900 °C. At 1000 °C, a 100 nm thick AlN layer oxidizes completely. For nitrogen, the layer is stable up to 1000 °C. The activation energy of the samples was determined from leakage current measurements at different sample temperatures, in the range between 25 and 300 °C. Up to an annealing temperature of 700 °C, the leakage current in the thin filmmore » is dominated by Poole-Frenkel behavior, while at higher annealing temperatures, a mixture of different leakage current mechanisms is observed.« less
Authors:
; ; ;  [1] ;  [2]
  1. Institute of Sensor and Actuator Systems, Vienna University of Technology, Vienna 1040 (Austria)
  2. CTR Carinthian Tech Research AG, Villach 9524 (Austria)
Publication Date:
OSTI Identifier:
22413114
Resource Type:
Journal Article
Resource Relation:
Journal Name: Journal of Applied Physics; Journal Volume: 117; Journal Issue: 6; Other Information: (c) 2015 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND SUPERFLUIDITY; ACTIVATION ENERGY; ALUMINIUM; ALUMINIUM NITRIDES; ANNEALING; DEPOSITION; DIFFUSION; ELECTRICAL PROPERTIES; LAYERS; LEAKAGE CURRENT; NITROGEN; OXYGEN; PHASE STABILITY; PIEZOELECTRICITY; SILICON; STRESSES; TEMPERATURE DEPENDENCE; THIN FILMS; X-RAY DIFFRACTION