| Summary: | 碩士 === 南台科技大學 === 電機工程系 === 92 === In this research, TaOx and HfOx thin films were deposited onto (100) n+-Si wafers by radio frequency magnetron sputtering. The effect of substrate pretreatment by BOE solution on the properties of tantalum oxide films was investigated. The characteristics of tantalum oxide films after post deposition annealing were studied. The results show that the leakage current is larger for tantalum oxide films grown on substrates with BOE pre-treatment. After 600℃ furnace annealing, the structure of TaOx remains amorphous even as the TaOx thickness decreases from 500Å to 100Å. The leakage current density is about 1×10-6 A/cm2 at 3MV/cm for both plasma annealing and furnace annealing as increasing annealing time. The plasma annealing can reduce both fixed oxide charges and interfacial trap charges, and is more effective than furnace annealing for reducing Equivalent Oxide Thickness.
The properties of hafnium oxide thin films were also investigated. The in-situ annealing and postannealing were implemented to investigate the effects of annealing on the current-voltage（I-V）and film structure, and to compare with the properties of TaOx films. The results show that the leakage current density of the as-deposited hafnium oxide is lower than the as-deposited tantalum oxide. For in-situ annealing, we found that the leakage current density in the HfOx thin films increases with increasing deposition substrate temperature. The XRD analysis reveals that the crystallization is the cause of higher leakage current density in HfOx thin films. When the HfOx thin films were annealed after deposition, we found that the leakage current density is larger than as-deposited HfOx thin films. This result is different from TaOx thin films which have lower leakage current annealed after deposition.
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