ECR plasma-assisted deposition of Al2O3 and dispersion-strengthened AlO2

摘要

Electron cyclotron resonance (ECR) O(sub 2) plasmas, in conjunction with electron-beam evaporation of Al, were used to grow thick AlO(sub x) films were varying but controlled composition and microstructure. The ion energy was varied from 30 to 190 eV, and growth temperatures varied from 35(degrees)C to 400(degrees)C. The ECR-film compositions were varied from AlO(sub 0.1) to Al(sub 2)O(sub 3) by controlling the plasma parameters and Al deposition rate. The Al-rich alloys exhibited a fine-grain (10-100 nm) fcc Al microstructure with (gamma)-Al(sub 2)O(sub 3) precipitates ((approximately)1 nm), similar to that found in the gigapascal-strength O-implanted Al. The measured hardness of the ECR Al-O alloys ((approximately)3 GPa) was also similar to the ion-implanted alloys which implies that the yield strength of the ECR material is (approximately)1 GPa. Moreover, the Al-O alloys retain much of the elasticity of the Al metal matrix. As-deposited stoichiometric Al(sub 2)O(sub 3) samples grown with an applied bias of -140 to -160 V at 400(degrees)C were fine-grain polycrystalline (gamma)-Al(sub 2)O(sub 3). The amorphous films crystallized into the (gamma)-Al(sub 2)O(sub 3) phase upon vacuum annealing to 800(degrees)C.