Preparation of oxide semiconductor films via solution deposition method and investigation on the interfaces inside the films

以乙酸锌为原料，加入二乙醇胺，再加入单乙醇胺和乙偶姻制备溶胶，制备氧化锌薄膜。制备的溶胶浓度为0.5mol/L。单乙醇胺和乙偶姻的共添加量分别与锌等摩尔和半摩尔。使用的基板是耐热玻璃和具有130 nm厚的氧化物层的硅晶片。采用一种非离子表面活性剂对硅片进行涂覆。将通过浸涂程序沉积的膜在600至900 ℃下加热以形成氧化物膜。为了研究薄膜晶体管，在硅片和氧化锌层之间沉积了氧化锆薄膜，通过快速热处理，使氧化锌薄膜的c轴垂直于衬底表面。在500-600℃加热时，薄膜的电阻率在1 ~ 5 Ωcm之间，随温度升高电阻率增大。电阻率最低的薄膜，载流子密度为10 ~<16>（^2）cm ~ 3，迁移率为1-5 cm ~ 2/Vs。在SiO_2/Si基片上淀积的这种薄膜的电导率测量表明，通过绝缘SiO_2层有相当大的漏电流。这种泄漏归因于SiO2层的缺陷。为了钝化SiO_2层，研究了用Ta_2O_5或ZrO_2覆盖沉积。得到了表面光滑的ZrO_2薄膜，该薄膜可防止绝缘层漏电。由此制备的ZnO/ZrO_2/SiO_2/Si多层膜具有优良的薄膜晶体管特性。

Zinc oxide films were fabricated using a sol, which was prepared from zinc acetate with additions of diethanolamine, and co-addition of monoethanolamine and acetoin. The prepared sol was 0.5 mol/L concentration. The co-added amounts of monoethanolamine and acetoin were equimolar and a half molar to zinc, respectively. The substrates used were heat resistant glass and silicon wafer with oxide layer of 130 nm thick. A non-ionic surfactant was used for coating on silicon wafer. Deposited films by a dip-coating procedure were heated at 600 to 900 to form oxide films. In order to investigate the thin film transistor, zirconia thin film was also deposited between the silicon wafer and zinc oxide layer.By rapid heat treatment, zinc oxide films were oriented with c-axis perpendicular to the substrate surface. The electrical resistivity of the films heated at 500-600℃ ranged 1 to 5 Ωcm, and became larger when heated higher temperature. The film of the lowest resistivity, had a carrier density of 10^<16> cm^3 and a mobility of 1-5 cm^2/Vs. The measurement of electrical conductivity of this film deposited on SiO_2/Si wafer revealed a considerable amount of leakage current through the insulating SiO_2 layer. This leakage was attributed to defects of the SiO2 layer. In order to passivate the SiO_2 layer, cover deposition with Ta_2O_5 or ZrO_2 was examined. The ZrO_2 film with smooth surface was obtained and the film prevented the leakage through the insulating layer. Thus manufactured multilayered film, ZnO/ZrO_2/SiO_2/Si, exhibited an excellent feature as a thin film transistor.