Tuning plasma time, power, and substrate bias for high-throughput atomic layer deposition of AlN

Plasma-enhanced atomic layer deposition (PEALD) has benefited the deposition of nitride thin films such as aluminum nitride (AlN) by enabling extensive control over their material properties. Moreover, the deposition rate, that is often cited as Achilles' heel of ALD for industrial application of nitride films, can be enhanced by combining the use of a plasma with an ALD platform designed for high throughput. In our work, the properties of the AlN film made by PEALD have been tailored by tuning the plasma time, plasma power, and RF substrate biasing. Refractive index values up to 2.0 have been measured for our films, which is typical for polycrystalline films deposited by PEALD. A negligible oxygen content < 0.2 at. % has been measured by Rutherford backscattering in the bulk of the films. The ALD cycle time of 7 s developed in this work is expected to help preventing oxygen incorporation from background species during deposition. Our results emphasize the critical role of plasma parameters in achieving targeted properties of AlN films while maintaining short cycle time, thereby broadening the potential applications for AlN deposited by PEALD.