Studies of Anodic Alumina Formed on Sputtered Thin Al Films
| Autor: | Chiu ,Re-Long, 邱瑞隆 |
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| Rok vydání: | 1995 |
| Druh dokumentu: | 學位論文 ; thesis |
| Popis: | 84 A systematic research about the effect of various processing parameters on the anodic oxide formation on Al thin films depos- ted on Si wafer coated with thermal oxide and borophosphosilica- te glass (BPSG) has been conducted in the present study. The co -rrelation of the compositional and microstructural results with dielectric properties was made. The best process condition of anodic aluminum oxide formation for IC applications has been es- tablished. Silicon nodules present in the Si dopped Al film are oxidized to various degree during anodizing. The silica formed in the Si nodules is amorphous and somewhat porous, possibly due to oxygen evoution associated with Si anodization. A dark rim was found to surround each nodule in the anodic oxide film. This rim is shown to be thicker amorphous Al2O3 material, and its origin is attri- buted to the faster oxidation rate in the vicinity of Si nodules, thus forming Al2O3 spike which lower the dielectric properties. Al2Cu present in the Cu dopped Al film are oxidezed to form Al2O3 at about the same rate as the surrounding Al matrix. Copp- er is rejected by Al2O3 and accumulates at the Al2O3/Al interfa- ce. The anodic oxide formed on pure Al films exhibit the best d- ielectric properties compared with those formed on films doped with Si and/or Cu. Large voids were formed at the oxide layer in the Al- Si film, this film exhibits the worst dielectric propert- ies compared with the Al and Al-Si-Cu films. Oxide films formed at 8 ℃ and 25 ℃ are amorphous with excelle- nt dielectric properties, leakage current lower than 500 nA at 7.5 MV/cm and no breakdown up to 7.5 MV/cm. Partially crystalli- ne r''-Al2O3 is grown at the upper half of the 58 ℃ oxide film. This film exhibits much inferior dielectric properties than the lower temperature films. Carbon is incorporated into the top po- rtion of the oxide films from the electrolyte during anodizing and it has little effect on the crystalline oxide formation. Ox- ygen penetrates |
| Databáze: | Networked Digital Library of Theses & Dissertations |
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