Enhancement of the chemical stability of hydrogenated aluminum nitride thin films by nitrogen plasma treatment

Hydrogenated aluminum nitride (AlN:H) thin films have been deposited on sil icon (100) wafers by radio frequency reactive magnetron sputtering. Althoug h the as-deposited AlN:H films exhibit smooth surface and low oxygen concen tration, they are chemically unstable. The presence of N-H bonds is known t o cause chemical instability and an increase of the etching rate in KOH sol ution. The AlN:H films, which are treated with nitrogen plasma generated by a microwave system, show a much lower etching rate than that of as-deposit ed AlN:H or even as-deposited AlN films. After nitrogen plasma treatment, t he Al-N bonding density in AlN:H films has increased sharply, while N-H bon ding density has decreased. It means that the hydrogen atoms in the films d iffuse out during the process, so that more chemically-stable AlN:H films a re formed. (C) 2001 The Electrochemical Society.