Ferroelectricity in boron-substituted aluminum nitride thin films

John Hayden, Mohammad Delower Hossain, Yihuang Xiong, Kevin Ferri, Wanlin Zhu, Mario Vincenzo Imperatore, Noel Giebink, Susan Trolier-Mckinstry, Ismaila Dabo, Jon Paul Maria

Research output: Contribution to journalArticlepeer-review

Abstract

This manuscript demonstrates ferroelectricity in B-substituted AlN thin films and a complementary set of first-principles calculations to understand their structure-property relationships. Al1-xBxN films are grown by dual-cathode reactive magnetron sputtering on (110)W/(001)Al2O3 substrates at 300°C at compositions spanning x=0 to x=0.20. X-ray diffraction studies indicate a decrease in both the c and a lattice parameters with increasing B concentration, resulting in a decrease in unit cell volume and a constant c/a axial ratio of 1.60 over this composition range. Films with 0.02≤x≤0.15 display ferroelectric switching with remanent polarizations exceeding 125μCcm-2 while maintaining band gap energies of >5.2eV. The large band gap allows low frequency hysteresis measurement (200 Hz) with modest leakage contributions. At B concentrations of x>0.15, c-axis orientation deteriorates and ferroelectric behavior is degraded. Density-functional theory calculations corroborate the structural observations and provide predictions for the wurtzite u parameter, polarization reversal magnitudes, and composition-dependent coercive fields.

Original languageEnglish (US)
Article number044412
JournalPhysical Review Materials
Volume5
Issue number4
DOIs
StatePublished - Apr 2021

All Science Journal Classification (ASJC) codes

  • Materials Science(all)
  • Physics and Astronomy (miscellaneous)

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