CHARACTERISTICS OF ITO FILMS DEPOSITED BY DC MAGNETRON SPUTTERING USING VARIOUS SINTERED INDIUM-TIN-OXIDE TARGETS

Indium Tin Oxide (ITO) films were deposited on nonalkali glass substrate by dc magnetron sputtering using high density ITO targets which were prepared under different conditions such as conductivity and micro-pore size. In order to investigate correlation between target and film properties, depositions were carried out at total gas pressure (P-tot) of 0.5 Pa, substrate temperature (T-s) of RT similar to 300 degrees C, oxygen flow ratio [O-2/(O-2+Ar)] of 0 similar to 1.5% and dc power of 100W. In the case of conductivity, high conductivity target A2 showed relatively high stability in electrical property with increasing target erosion ratio. Optimum O-2 addition ratio to obtain the lowest resistivity was decreased with increasing target erosion ratio. High conductivity ITO target could lead to decrease in micro-nodule formation on the target surface because of high cooling efficiency. In the case of micro-pore size, clear difference in resistivity of the films was not observed between two targets for 11 hours sputtering where target surface was eroded about 20%. Whereas, target B2 showed small degradation in resistivity with increasing sputtering time after 11 hours compared to large micro-pore size target. Optimum oxygen ratio to obtain the lowest resistivity was decreased with increasing substrate temperature. The lowest resistivity was. 1.06x10(-4) Omega cm for the film deposited using target B2 at O-2/(O-2+Ar) ratio of 0.05% and at T-s = 300 degrees C.