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Nanoprobe mechanical and piezoelectric characterization of Sc x Al 1− x N(0001) thin films
Author(s) -
Žukauskaitė Agnė,
Broitman Esteban,
Sandström Per,
Hultman Lars,
Birch Jens
Publication year - 2015
Publication title -
physica status solidi (a)
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.532
H-Index - 104
eISSN - 1862-6319
pISSN - 1862-6300
DOI - 10.1002/pssa.201431634
Subject(s) - materials science , piezoresponse force microscopy , nanoindentation , piezoelectricity , thin film , nanoindenter , piezoelectric coefficient , scandium , sputter deposition , analytical chemistry (journal) , composite material , optoelectronics , sputtering , nanotechnology , dielectric , ferroelectricity , metallurgy , chemistry , chromatography
Nanoindentation with in‐situ electrical characterization is used to investigate piezoelectric scandium aluminum nitride (Sc x Al 1− x N) thin films with Sc contents up to x = 0.3. The films are prepared by reactive magnetron sputtering using Al 2 O 3 substrates with TiN seed layers as bottom electrodes at a substrate temperature of 400 °C. X‐ray diffraction shows c ‐axis oriented wurtzite Sc x Al 1− x N, where the crystal quality decreases with increasing x . Piezoresponse force microscopy in mapping mode reveals a single piezoelectric polarization phase in all samples. The hardness decreases from 17 GPa in AlN to 11 GPa in Sc 0.3 Al 0.7 N, while reduced elastic modulus decreases from 265 GPa to 224 GPa, respectively. Both direct and converse piezoelectric measurements are demonstrated by first applying the load and generating the voltage and later by applying the voltage and measuring film displacement using a conductive boron doped diamond nanoindenter tip. The Sc 0.2 Al 0.8 N films exhibit an increase in generated voltage in comparison to AlN and a correspondingly larger displacement upon applied voltage, comparable to results obtained by double beam interferometry and piezoresponse force microscopy.