Growth of aluminum nitride thin films prepared by plasma-enhanced atomic layer deposition

Abstract

Aluminum nitride (AlN) thin films were deposited by atomic layer deposition from aluminum chloride (AlCl 3) and an ammonia/hydrogen plasma. The most important role of the ammonia/hydrogen plasma was to act as a reducing agent to extract Cl from AlCl 3, and to form AlN subsequently. The growth rate was saturated at ∼0.042 nm/cycle, and the thickness was proportional to the number of reaction cycles. Repeating this reaction cycle led to precisely controlled growth. The film properties were analyzed using Auger electron spectroscopy, X-ray photoelectron spectroscopy, Rutherford backscattering spectroscopy and time-of-flight elastic recoil detection analysis. The concentration of chlorine and hydrogen impurities was 0.23 and 2.01 at.%, respectively. AlN films showed good anti-oxidation properties when O 2 was annealed at 650 °C for 30 min.