N-doped Al2O3 thin films deposited by atomic layer deposition

The present study focused on nitrogen doped Al2O3 thin films using atomic layer deposition, varying the deposition temperature from 55 to 170 °C. Al2O3 thin film growth rate and electrical properties were mostly dependent on deposition temperature. Nitrogen concentration decreased from 2.7 to 2.4% with increasing deposition temperature. X-ray photoelectron spectroscopic analysis confirmed that nitrogen doping in Al2O3 decreased formation of oxygen related defects, including non-lattice oxygen. Surface morphology analyses also showed that N-doping reduced Al2O3 film surface roughness. Reduced oxygen related defects significantly reduced leakage current by 1000 times when comparing with as-deposited films. Minimum leakage current (5 × 10−10 A/cm2) was observed for N-doped Al2O3 film deposited at 170 °C and post-annealed at 400 °C, including a decrease by 10 times through N-doping.