Studies on fully transparent Al-Sn-Zn-O thin-film transistors fabricated on glass at low temperature

High-performance fully transparent Al-Sn-Zn-O thin-film transistors (ATZO TFTs) with excellent electrical performance have been successfully fabricated by RF magnetron sputtering on glass at low temperatures. Two kinds of appropriate ATZO compositions are compared from several perspectives, including film material characteristics, device electrical performances, and fabrication process conditions. Finally, we achieve two excellent ATZO TFTs with competitive advantages. The ATZO TFT with larger amounts of dopants exhibits a superior field effect mobility mu(FE) of 102.38 cm(2)V(-1)s(-1), an ON/OFF current ratio (I-on/I-off) of 1.18 x 10(7), and a threshold voltage V-T of 1.35V. The device with smaller amounts of dopants demonstrates better crystal quality and an excellent subthreshold swing SS of 155mV/dec. Furthermore, it is less affected by oxygen partial pressure. The ATZO thin films display a high transmittance of over 80% in the visible light range. (C) 2015 The Japan Society of Applied Physics