Study On The Pulsed Laser Deposited Process, Structure-controlling And Properties Of Iridium Oxide Thin Films

In addition to the low resistivity, super anti-corrosion, IrO₂ thin films possess some other interesting properties, such as excellent diffusion barrier properties preventing the diffusion of elements (O, Zr, Pb, Ti) at high temperature and attractive electrochemical properties. From a practical application point of view, IrO₂ thin films have attracted much attention as for bottom electrode materials in DRAMs and FeRAMs, durable electrode material for chlorine or oxygen evolution, etc. As pH sensor materials, IrO₂ thin films can compensate the defects of the glass electrode, which will aggravate the alkali interference problem and become less stable at higher temperature than 100℃.In the present dissertation, IrO₂ thin films were prepared on the substrates of Si(100), SiO₂/Si(100) and quartz glass respectively by two methods, namely oxidizing Ir films in air and depositing IrO₂ films at oxygen environment. In order to obtain IrO₂ films with high quality, emphasis were given on the effects of pulsed laser deposition (PLD) parameters (such as oxygen pressure, substrate temperature, output energy of laser, distance between target and substrate) and subsequent annealing on the microstructure and properties of IrO₂ films. Besides, according to its applied condition, the stabilities of IrO₂ films in the environment of acidic and alkaline aqueous solution at temperature above 100℃ and high temperature with low oxygen pressure.The experimental results showed that the root mean roughness of Ir films deposited on Si(100) was below than 1nm. After oxidized at atmosphere in the temperature range of 700-850℃, IrO₂ formed at the surface of Ir films and the roughness of IrO₂ films increased with the increase of oxide temperature. Substrates had strong effect on the surface structure of IrO₂ films. The pre-treatment of Si(100) was beneficial to the improvement of the surface of IrO₂ films, at the oxidative temperature of 750℃, the roughness of IrO₂ films deposited on SiO₂/Si(100) substrate was 3.7nm(1×1μm).PLD parameters had strong effect on the phase and structure of IrO₂ films during the course of PLD by using Ir target at an oxygen atmosphere. The optimum conditions of deposited IrO₂ films on Si(100) by PLD were found: oxygen pressure...