By Electron Beam Evaporation Preparation Of Doped Zirconia Films

Much attention has been paid on pure or doped zirconia thin films because of their high melting point, low heat conductivity, high ionic conductivity and chemical durability. In the case of metal-oxide-semiconductor (MOS) devices and high-temperature superconductor (HTS) wires, zirconia epitaxial thin films are promising buffer layers and have been intensely studied in the past two decades. The growth of epitaixal films with desired crystalline orientation and smooth surface plays a key role in these applications. In this thesis, the alumina doped and yttria doped zirconia thin films were deposited by electron beam evaporation on Si(100) substrates. The main research work and conclusions are as follow:1. The thin films were a mixture of Zr5Al3O0.34 and ZrO2 when the evaporating material is comprised of 16.3 mol% and 32.7 mol% alumina.2. A series of deposition experiments were performed using the 16.3mol% alumina doped zirconia evaporating source material. It was found that the resultant thin films were amorphous at substrate temperature (Ts) below 400℃. The films began to crystallize at 700℃and showed strong polycrystalline character at 750-800℃. No evident crystallization was present when electron beam flux was below 30mA. The films with best crystallization were obtained when flux was 40-50mA. Further increasing the flux, the crystallization became worse. The optimal deposition parameters were found to be: substrate temperature 750℃and flux 40mA. Using this optimal deposition parameters, (112) preferential orientation Zr5Al3O0.34 thin films were prepared.3. The amorphous films deposited at low temperatures were annealed at high temperature. The results showed weak crystallization even the anneal temperature was as high as 900℃.4. Ion texturing (ITEX) experiments were carried out on 16.3 mol% alumina doped zirconia thin films by oblique ion bombardment. The effect of bombardment energy on the crystallization was studied by fixing the ion dosage and incidence angle. After bombardment, the amorphous films became weak crystallized. On the contrary,...