Effects of Growth Temperature and Annealing on Properties of Zn3Sn2O7 Thin Films and Application in TFTs

The effects of growth temperature and annealing on the physical properties of Zn3Sn2O7 thin films were investigated in this work. The Zn3Sn2O7 thin films were deposited on glass substrates by radio frequency (rf) magnetron sputtering. It is found that the films are amorphous regardless of the growth temperature. The film grown at room temperature shows the highest mobility of 8.1 cm(2) V-1 s(-1) and the lowest carrier concentration of 2.0 x 10(15) cm(-3). The highest carrier concentration of 1.6 x 10(19) cm(-3) is obtained at the growth temperature of 250A degrees C. Annealing treatment of the Zn3Sn2O7 thin films resulted in increases of carrier concentration and mobility. The average transmittance of the as-deposited and annealed films reaches 80%. By using a Zn3Sn2O7 thin film as the channel and a Ta2O5 thin film as the insulating layer, we fabricated transparent Zn3Sn2O7 thin-film transistors with field-effect mobility of 21.2 cm(2) V-1 s(-1), on/off current ratio of 10(5), threshold voltage of 0.8 V, and subthreshold swing of 0.8 V/decade.