Improving quality of AlN films on GaAs substrate via in-situ plasma pre-treatment in plasma enhanced atomic layer deposition

Using plasma-enhanced atomic layer deposition (PEALD), we achieved the low-temperature growth of aluminum nitride (AlN) films on GaAs substrate. The effect of in-situ plasma pre-treatment on AlN films growth has been thoroughly investigated in detail. After in-situ plasma pre-treatment, the surface roughness closely matched that of the substrate, the interfaces between AlN films and GaAs substrate were extremely sharp, and the film density increased from 3.05 g/cm3 to 3.15 g/cm3. Additionally, the oxygen content in the AlN films decreased from 35.5 % to 18.8 %. This indicates that in-situ plasma pre-treatment is an effective method for reducing impurity content and improving film quality.