Low temperature aluminum nitride thin films for sensory applications

Journal Article · Fri Jul 15 04:00:00 EDT 2016 · AIP Advances

DOI:https://doi.org/10.1063/1.4959895· OSTI ID:22611443

Yarar, E.; Zamponi, C.; Piorra, A.; Hrkac, V.; Kienle, L. ^[1]

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1. Institute for Materials Science, Chair for Synthesis and Real Structure, Kiel University, D-24143 Kiel (Germany)

A low-temperature sputter deposition process for the synthesis of aluminum nitride (AlN) thin films that is attractive for applications with a limited temperature budget is presented. Influence of the reactive gas concentration, plasma treatment of the nucleation surface and film thickness on the microstructural, piezoelectric and dielectric properties of AlN is investigated. An improved crystal quality with respect to the increased film thickness was observed; where full width at half maximum (FWHM) of the AlN films decreased from 2.88 ± 0.16° down to 1.25 ± 0.07° and the effective longitudinal piezoelectric coefficient (d{sub 33,f}) increased from 2.30 ± 0.32 pm/V up to 5.57 ± 0.34 pm/V for film thicknesses in the range of 30 nm to 2 μm. Dielectric loss angle (tan δ) decreased from 0.626% ± 0.005% to 0.025% ± 0.011% for the same thickness range. The average relative permittivity (ε{sub r}) was calculated as 10.4 ± 0.05. An almost constant transversal piezoelectric coefficient (|e{sub 31,f}|) of 1.39 ± 0.01 C/m{sup 2} was measured for samples in the range of 0.5 μm to 2 μm. Transmission electron microscopy (TEM) investigations performed on thin (100 nm) and thick (1.6 μm) films revealed an (002) oriented AlN nucleation and growth starting directly from the AlN-Pt interface independent of the film thickness and exhibit comparable quality with the state-of-the-art AlN thin films sputtered at much higher substrate temperatures.

• OSTI ID: 22611443
• Journal Information: AIP Advances, Journal Name: AIP Advances Journal Issue: 7 Vol. 6; ISSN AAIDBI; ISSN 2158-3226
• Country of Publication: United States
• Language: English

Related Subjects

75 CONDENSED MATTER PHYSICS
SUPERCONDUCTIVITY AND SUPERFLUIDITY
ALUMINIUM NITRIDES
CONCENTRATION RATIO
CRYSTAL GROWTH
CRYSTALS
DEPOSITION
DIELECTRIC MATERIALS
INTERFACES
LOSSES
MICROSTRUCTURE
PERMITTIVITY
PIEZOELECTRICITY
SPUTTERING
SUBSTRATES
SURFACES
SYNTHESIS
THICKNESS
THIN FILMS
TRANSMISSION
TRANSMISSION ELECTRON MICROSCOPY