The Study On Preparation And Properties Of Amorphous Al₂O₃Thin Films By RF Magnetron Sputtering

Thin film transistor (TFT), which mainly consists of deposited semiconductor,metal and insulator film, is the core component of flat panel display. At present, theinsulating layer of the TFT is usually made of SiO2. With the development ofelectronic device, SiO2thin film is not able to meet the needs of TFT. As a new kindof dielectric material, Al2O3is used to replace the SiO2to produce TFT. Al2O3has alot of advantages, such as low preparation cost, chemical stability, excellent physicalproperties etc. In addition, the amount of Al is very abundant in our country.Therefore, the research on Al2O3thin film has the great theoretical significance andpractical value.In this paper, Al2O3thin films were prepared on the glass and the flexiblesubstrate (polyimide, PI) by radio frequency magnetron sputtering process in whichthe target material was high purity Al2O3powder. The different experimentalconditions to produce Al2O3film, such as oxygen flux and sputtering power andsputtering time, were researched and optimized. Then the Probe Profilometer, X rayDiffraction (XRD), Atomic Force Microscopy (AFM) and Ultraviolet-visibleSpectrophotometer (UV-vis Spectrophotometer) were used to analyze the influence ofpreparation process parameters on the surface morphology and optical properties ofAl2O3films.The experimental results show that: the Al2O3films with different characteristicshave been prepared under the different process parameters, such as power, targetdistance, the amount of oxygen and sputtering time. The microstructures of all theprepared Al2O3films are amorphous. With the decrease of oxygen flow, the increaseof the sputtering power and the extension of sputtering time, the thickness of Al2O3films will increase; with the increase of oxygen flow, the decrease of the sputteringpower and the extension of sputtering time, the particle size and roughness of Al2O3films will lower; and with the increase of oxygen flow, the increase of the sputteringpower and the reduction of sputtering time, the Al2O3films would have a wider bandgap, which the maximum is up to4.21eV.Besides being a new dielectric material, the Al2O3films are also widely usedin the packaging field. Considering the band gap of the prepared amorphous Al2O3films is likely to be compatible for antibacterial. The paper studied the antimicrobialproperty of the amorphous Al2O3films referring to the traditional photocatalytic oxidefilms (such as CdO, ZnO, SnO2). It turns out that the amorphous Al2O3films reflectbetter antimicrobial property comparing with other oxide films. The antibacterial rateafter24hour is up to98.6%. In addition, the antimicrobial property of SnO2:F thinfilm has also been investigated. Through F element doping and optimization ofprocess conditions (the amount of oxygen:0,1,2sccm), the antimicrobial rate ofSnO2films is up to99.4%.