INFLUENCE OF SUBSTRATE TEMPERATURE AND ARGON FLOW RATE ON GROWTH OF TiO2 THIN FILMS BY MOCVD

• Main Author: ARIEF MUSTAJAB ENHA MARYONO (NIM : 10210091); Pembimbing : Pepen Arifin, Ph.D, MUHAMMAD
• Format: Final Project
• Language: Indonesia
• Online Access: https://digilib.itb.ac.id/gdl/view/20307
• Institution: Institut Teknologi Bandung

This experiment identifies the influence of substrate temperature and Argon flow rate on growth of TiO2 thin films by MOCVD. Properties of thin films as well as <br /> <br /> <br /> crystal structure, surface morphology, stoichiometry, and growth rate were investigated with related to influence of these growth parameters. Titanium dioxide (TiO2) known as material with high functionality, environmental friendly, and has many application. TiO2 as thin film has many important roles for optical and electronic applications. Among several methods for thin film growth, MOCVD offers advantages of high density and high purity film, good adhesion on substrate, and also can grow uniform and homogen film on relatively large area and complex surface. Another advantage is growth temperature can be relatively low. For growth high quality films, growth condition in MOCVD should be optimized. A systematic and comprehensive study is needed to optimize several growth parameters. Among several studies, the experimental ex-situ study to identify influence of growth parameters on growth mechanism and film properties is widely used to optimize thin film growth by MOCVD. This experiment focused in study on influence of substrate temperature and Argon <br /> <br /> <br /> flow rate. These growth parameters related to energy required for growth process and mass transport of vapour precursor. Influence of both growth parameters important to be identified on growth of TiO2 thin films in order to get optimal growth condition for high quality thin films. In this experiment, TiO2 thin films grown in two series of growth conditions. First series grown with several substrate temperatures, from 350 oC to 500 oC, and the second with several Argon flow rates, from 50 sccm to 200 sccm. Both series of films characterized with XRD, SEM, and EDS technique. The result from thin <br /> <br /> <br /> film characterizations were interpreted and analyzed, related to the influence of growth parameters, as well crystal structure, surface morphology, stoichiometry, <br /> <br /> <br /> and growth rate. TiO2 thin films which grown at substrate temperature within range 350 oC to 500 oC, have polycrystalline structure with anatase phase. Form and size of crystal grains depend on growth characteristic influenced by temperature substrat, as well explained by real structure zone model. At these range of temperatures, TiO2 thin films have some carbon within films from 2,13 % up to 3,05 % which intrude on <br /> <br /> <br /> TiO2 thin films stoichiometry. At temperature below 400 oC, growth of TiO2 thin films limited by surface chemical kinetic with activation energy 86,47 kJ/mol. At temperature above 400 oC, thin films growth limited by mass transport phenomena with activation energy 9,07 kJ/mol. TiO2 thin films also have been grown with Argon flow rate from 50 sccm and substrate temperature 500 oC. Grain size of films grown larger with increasing of <br /> <br /> <br /> Argon flow rate. The thickness of films also increasing as faster Argon flow rate. This concern related to increasing of growth rate with faster Argon flow rate, <br /> <br /> <br /> because growth mechanism in this temperature limited by mass transport phenomena which one of influencing aspect is gas flow rate. In this thin film growth with several Argon flow rates, TiO2 thin films still have some carbon <br /> <br /> <br /> composition within films from 1,05 % to 3,95 %. The Influence of substrate temperatures and Argon flow rates on several properties of TiO2 thin films, including crystal structure, surface morphology, form and size of crystal grain, also growth kinetics have been identified. However, dependability of both growth parameters with quantity of carbon within TiO2 thin <br /> <br /> <br /> films have not been identified yet. It needs more detailed study on influence of other growth parameters, as like as Oxygen flow rate, to restrain quantity of <br /> <br /> <br /> carbon within TiO2 thin films. With the result that high purity and good stoichiometric TiO2 thin films can be achieved.