| Summary: | 博士 === 國立交通大學 === 電子研究所 === 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
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