Plasma-Assisted Atomic Layer Growth of High-Quality Aluminum Oxide Thin Films

Thin aluminum oxide (Al 2 O 3 ) films were grown by the plasma-assisted atomic layer controlled deposition (PAALD) method using Dimethylethylamine alane [(CH 3 ) 2 (C 2 H 5 )N:AlH 3 ] (DMEAA). Al was deposited by the PAALD method, then the Al films were oxidized into Al 2 O 3 by plasma oxidation in the same chamber without breaking the vacuum. Al 2 O 3 thin films of 15 nm thickness were prepared by repetition of this process. Thus prepared Al 2 O 3 thin films exhibited a refractive index of 1.68. The thickness and the refractive index fluctuation of the film over a 4 inch wafer were ±2.3% and ±1.9%, respectively, for the deposited films. The leakage current density and breakdown field were measured to be about 10 -8 A/cm 2 at 1 MV/cm and 7 MV/cm, respectively. Considerable improvement of the electrical properties was realized by the post oxygen-plasma annealing at 200°C.