Electrochemical Characteristics of Silicon-Doped Tin Oxide Thin Films for Application of Lithium Secondary Micro-Battery Anode

The SnO2 thin films doped with traces of silicon were deposited on the p-type (100) Si substrate by the r.f. magnetron sputtering method from Sn0.94Si0.06O2 target for the application of lithium secondary micro-battery anode. The crystal orientation of tin oxide thin films was changed from (110) to (101) or (211) with the increase of the substrate temperature. Contrarily, the crystallization of tin oxide thin films, which were heat-treated in the RTA furnace from 450℃ to 650 ℃ under the O2 ambient, did not show significant difference. As a result of the electrochemical analysis, we could see that the irreversible capacity was reduced during the first discharge/charge cycle. Capacity increased with the increase of substrate temperature, but decreased with the increase of RTA temperatures. In particular, the maximum value of reversible capacity was 700mAh/g under the deposition condition of the substrate temperature of 300℃ and the Ar:O2 ratio of 7:3.