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[摘要]：Thermal properties of various silver precursors known in the literature were evaluated in order to discover which precursor is the most suitable one for plasma-enhanced atomic layer deposition (PEALD) of silver thin films. Ag(fod)(PEt3) (fod = 2,2-dimethyl-6,6,7,7,8,8,8-heptafluorooctane-3,5-dionato) was found to be the best choice. Using Ag(fod) (PEt3) together with plasma-activated hydrogen, silver thin films were deposited at growth temperatures of 120-150 degrees C, and ALD-type saturative growth was achieved at 120-140 degrees C. At 120 degrees C, the growth rate was 0.03 nm per cycle. The plasma exposure time had also an effect on the growth rate: with shorter exposure times, the growth rate was lower over the whole deposition area. The films deposited at 120 degrees C contained relatively small amounts of impurities, but these still affected the electrical properties of the films. The resistivities were relatively low: about 20 nm thick films had a resistivity of 6-8 mu Omega . cm. The morphology and the crystal structure of the films were analyzed as well. |
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