Polarity tuning of crystalline AlN films utilizing trace oxygen involved sputtering and post-high-temperature annealing

The polarity tuning of AlN films via introducing a period of trace oxygen supply in the initial sputtering process was demonstrated. High-temperature annealing was further implemented to improve the crystal quality of AlN. High-quality pure N-polar AlN film could be achieved by sputtering with pure N-2 gas. When trace oxygen was intentionally inputted in the sputtering chamber and its supply time surpassed 150 s, the AlN surface polarity transmitted to pure Al-polar. After optimization, the full widths at half of maximum of X-ray rocking curves for (0002)/(10-12) reflection were improved to 41.3/132.5 arcsec for N-polarity and 38.2/158.7 arcsec for Al-polarity.

Automated summary

This study demonstrated the polarity tuning of AlN films by introducing trace oxygen supply and high-temperature annealing, successfully achieving high-quality N-polar and Al-polar AlN films. High crystal quality was obtained through sputtering with pure N-2 gas, and after optimization, the X-ray rocking curves for N-polarity and Al-polarity were significantly improved.