Silicon Preferred Orientation Of Strontium Barium Niobate Thin Films By Magnetron Sputtering Deposition

Strontium barium niobium (Sr_xBa_1-xNb₂O₆, 0.2100X) possesses the largest diagonal electro-optic coefficient, excellent piezoelectric, pyroelectric properties and photorefractive sensitivity. SBN has currently been investigated as a potential material for many micro-device applications such as ferroelectric waveguide electro-optic modulators, DRAM and infrared detectors, etc. Transparent Conductive Oxide (TCO) is an important material in opto-electronic devices. It is now applied widely as electrodes of solar battery, liquid crystal display, against frost glass of car etc. The designing, fabricating and characterizing of SBN and ITO films have become the key focuses of film optoelectronics due to their considerable application potential.Since the lattice mismatch between Silicon substrates and SBN thin films is so large that it has been proven difficulty growing prefered orientated SBN films directly on Si substrate, with Potassium ions doped SBN (KSBN) film as the buffer layer, highly c-axis preferred oritated SBN films were successfully grown on Si substrate. In this manuscript, SBN thin films with highly crystallization characteristics have been deposited on Si substrates by radio frequency (RF) reactive magnetron sputtering process. The microstructural and electric properties of the deposited films were characterized by x-ray diffractometer (XRD), atomic force microscopy (AFM), semiconductor parameter analyzer. The results indicated that the preferred orientation of SBN films was influenced by many deposition parameters such as PA_r/P_O2, sputtering pressure P_s, substrate temperature T_s RF power and annealing temperature Ta. At the parameters of PA_r/Po2=2/1, P_s =1.0Pa, T_s =300℃, P =300W and T_a=800℃, the SBN films showed an excellent preferred orientation along the c-axis, with smoothened morphology. The p-n junction effect was also found in our ITO/SBN/KSBN/Si structures, which is the characteristics of semiconductor materials, the junction effect has the close relationship with the presence of the buffer layer and the crystalline properties of SBN thin films.ITO thin film with high transmission and low electric resistance was grown by the RF magnetron sputtering. The microstructural, electric properties and optical properties of the deposited films were measured by x-ray diffractometer (XRD), reflectometertransmission spectrophotometer. The results indicated that the ITO films was heavily influenced by annealing temperature, when the annealing temperature was about 200℃ the transmission and electric resistance is improved. The transmission and electric resistance is further improved when the ITO films was post-annealed at 300℃ and 400℃, The electric resistance was reduced as the PA_r/P_O2 was greater than 1: 120, by the contrast the electric resistance was increased when the sputtering pressure P_s was greater than 1.0Pa. The sputtering power has weak affection to ITO films.When substrate temperature T_s was 200℃ and 100℃, the electric resistance was shown inhomogeneous on substrates, the same phenomenon was not found when the substrate temperature was 300℃ and 400℃, respectively. It indicated that the incident angle of sputtering particle and migration rate on the substrate has primary contributions to the electric resistance on glass substrate when the ITO film was grown at low temperature.