标题: | 制备不同镓含量之铟镓锌氧化物溅镀靶材及其应用于 上部闸极薄膜电晶体之研究 Fabrication of Indium Gallium Zinc Oxide Sputtering Targets with Various Gallium Contents and Their Applications to Top-gate Thin-film Transistors |
作者: | 巫俊升 谢宗雍 Wu,Jyun-Sheng Hsieh,Tsung-Eong 材料科学与工程学系所 |
关键字: | 铟镓锌氧化物;上部闸极;薄膜电晶体;Indium Gallium Zinc Oxide;Top-gate;Thin-film Transistors |
公开日期: | 2017 |
摘要: | 本研究制备不同镓(Gallium,Ga)含量的铟镓锌氧化物(Indium Gallium Zinc Oxide,IGZO)溅镀靶材,并用以制备上部闸极(Top-gate)薄膜电晶体(Thin-film Transistor,TFT)。研究第一部分以商用氧化铟(In2O3)、氧化镓(Ga2O3)及氧化锌(ZnO)粉体为起始原料,利用化学分散搭配机械研磨技术制成良好分散的奈米粉体,再以无压力式烧结制备化学剂量比为InGaZn2O5、InGaZnO4及InGa2ZnO5.5的三种IGZO靶材,X光绕射(X-ray Diffraction,XRD)分析显示1300C、6至8小时的烧结可完成单相结构的InGaZn2O5与InGaZnO4靶材,InGa2ZnO5.5靶材则为Ga2ZnO4和In2O3的两相混合结构,靶材相对密度均约为90%。第二部分研究使用上述三种靶材以溅镀法制备TFT的载子通道层,XRD分析显示所有初镀态及经300C、1小时大气退火之IGZO薄膜皆为非晶态,霍尔效应量测显示InGaZn2O5与InGaZnO4薄膜的载子浓度(Carrier Concentration,N)约为1019 cm3,电阻率(Resistivity,)约为102 Ω-cm,InGa2ZnO5.5薄膜的N值则仅1017 cm3,值约为1-3 Ω-cm;InGaZn2O5薄膜有最高的霍尔效应载子迁移率(Hall-effect Mobility,Hall)为21.17 cm2V1sec1,而InGa2ZnO5.5薄膜的Hall值仅有7.43 cm2V1sec1。电性量测显示300°C、1小时大气退火处理可显着提升TFT元件电性质,临界电压往负偏压偏移,次临界摆幅下降,含InGaZn2O5通道层的TFT有最佳的场效载子迁移率(Field-effect Mobility,FE)达9.95 cm2V1sec1,含InGa2ZnO5.5通道层的TFT之FE值则为1.97 cm2V1sec1,薄膜与元件性质随Ga含量上升而劣化的结果可归因于Ga3+抑制IGZO中氧空缺的产生,进而抑制了载子数量与迁移能力所致。 This study fabricates the indium gallium zinc oxide (IGZO) sputtering targets containing various Ga contents for preparing the active channel layers of top-gate thin-film transistors (TFTs). In first part of study, commercially available In2O3, Ga2O3 and ZnO powders served as the starting materials and a hybrid process of chemical dispersion and mechanical milling was adopted to form the aqueous suspensions containing finely dispersed, nano-scale oxide particles. A pressure-less sintering was then performed to yield the IGZO sputtering targets with relatively densities about 90% and stoichiometries of InGaZn2O5, InGaZnO4 and InGa2ZnO5.5. X-ray diffraction (XRD) indicated that sintering at 1300C for 6 to 8 hrs is able to form the single-phase InGaZn2O5 and InGaZnO4 targets whereas the InGa2ZnO5.5 target is comprised of mixed Ga2ZnO4 and In2O3 phases. The second part of study deposited the IGZO layers utilizing the self-parepared targets and XRD found that all as-deposited and 300C/1-hr annealed IGZO layers are amorphous. Hall effect measurement revealed the carrier concentrations (N) of InGaZn2O5 and InGaZnO4 layers are about 1019 cm3 and the resistivities () are 102 Ω-cm whereas the N and for InGa2ZnO5.5 layer are about 1017 cm3 and 1-3 Ω-cm, respectively. Moreover, InGaZn2O5 layer exhibited the highest Hall-effect mobility (Hall) of 21.17 cm2V1sec1 and the Hall value of InGa2ZnO5 layer was about 7.43 cm2V1sec1. Electrical measurement of TFTs found that the 300°C/1-hr annealing substantially improves the device performance that the shift of threshold voltages toward the negative bias side and the reduction of subthreshold swings are observed. The TFT containing InGaZn2O5 channel layer possessed the highest field-effect mobility (FE) of 9.95 cm2V1sec1 whereas the FE of TFT containing InGa2ZnO5.5 channel layer was 1.97 cm2V1sec1. The property degradation of IGZO layers and TFTs with high Ga contents can be ascribed to the suppression of oxygen vacancies due to the presence of Ga3+ which, in turn, limits the number and transport capability of charge carriers in such a IGZO layer. |
URI: | http://etd.lib.nctu.edu.tw/cdrfb3/record/nctu/#GT070251561 http://hdl.handle.net/11536/142698 |
显示于类别: | Thesis |