Investigation On The Optical And Electrical Properties Of IGZO Thin Films Fabricated By PLD

IGZO (InGaZnO), a kind of transparent oxide semiconductor, is now getting attentionby a lot of researchers. For the weakness of traditional oxide semiconductor, such aspoor transparency, low mobility, uncontrollable carrier concentration, it cannot satisfythe market demand. With the development of display technology people required highquality thin-film transistor which is used as control element in display. Because of theadvantages which is low preparation temperature, high mobility, controllable carrierconcentration, Amorphous IGZO become the one of the best material in depositing thechannel of thin-film transistor. The main reason for amorphous IGZO having such ahigh mobility is that the spatially spread metal ns orbital’s with isotropic character andthe overlap among the neighboring metal ns orbital’s is large, so that IGZO have greatcarrier transport paths, even a-IGZO which is long-range disorder keep highperformance in transfer characteristic. Researches do a lot of studying in a-IGZO,such as the effect of chemical Composition, VOin a-IGZO, and the issues aboutoptical sensitive and ambience sensitive. However, there is some practical problem tobe discussed. By using IGZO target prepared by us, we utilized PLD to deposit agroup of a-IGZO thin film samples to study two question：First, the electrical difference between the a-IGZO thin films deposit in differentthickness. By using Hall effect measurement, optical transmission measurement, thereason of the difference in electrical property was analyzed. We found the changingcharacter of VOin the deposition process and the different deposition rate between theheavy metal ions in a-IGZO might do to influence the optical and electrical propertyof a-IGZO.Second, the electrical difference between the a-IGZO thin films deposit in differentoxygen pressure. With increasing oxygen pressure in deposition process, fewer VOand poorer electrical performance in a-IGZO thin films is gained, which provedchanging oxygen pressure is a good method to obtain high quality a-IGZO thin films.