Papers by Author: Zdenek Hubička

Abstract: Thin films of SiC have been deposited using a hollow cathode sputtering technique. Several methods have been used including DC, RF, and pulsed sputtering. The films reported here have been deposited using DC and pulsed sputtering.

Abstract: This work analyzes the processing of Pb(Zr,Ti)O3 (PZT) thin films directly on copper-coated polymer films. PZT thin film deposition was performed onto the metallized Kapton® films using a single RF plasma jet. In order to reduce the interaction of PZT and Cu during the initial growth stage, an ultrathin amorphous TiO2-x seeding layer was sputter-deposited prior to PZT deposition. The film texture was a mixture of (111)-oriented perovskite nanocrystals, rutile and pyrochlore. Topography and piezoelectric in-plane and out-of-plane response of the films were evaluated using a commercial AFM adapted for piezoforce measurements. The as-deposited films were self-polarized with polarization pointing at the surface of the sample. Polarization was switchable and a piezoelectric hysteresis was obtained.

Abstract: Pulse modulated double hollow cathode RF plasma jet system with two separate independent nozzles made of BaTiO3 (BTO) and SrTiO3 (STO) was used for deposition of BSTO thin films on Si and on multi-layer Si/SiO2/TiO2/Pt substrates. Dielectric properties of BSTO layers strongly depend on ratio composition expressed by parameter x = Ba/(Ba+Sr) and on accuracy in presence of other elements. Space resolved optical emission spectroscopy (OES) was used mainly for monitoring of concentration of particles sputtered from the hollow cathode and for feedback correction of power supplied in both nozzles because applied power was responsible for sputtering speed of Ba and Sr particles. Main attention was focused on relation between ratio of spectral intensity of Ba, Ba+, Sr and Sr+ lines close to substrate and ratio of Ba and Sr concentration in the deposited film. 2D map of emission lines intensity distribution for Ba, Ba+, Sr, Sr+, Ti, Ar, and Ar+ for double hollow cathode plasma jet system with BTO and STO nozzles was created. OES was also used for observing of excess of Ti particles in final layer with negative effect on layer properties and for measurement of rotational temperature of OH radicals. Preliminary results of all these optical measurements are published in this paper. Deposited thin films were analyzed by X-ray diffraction, which confirmed presence of BSTO and STO perovskite phase in the films, by atomic force microscopy (AFM), by electron microprobe and by micro-Raman scattering measurement.

Abstract: Technology aspects and characterization of BaxSr1-xTiO3 (BST) films fabricated with low pressure plasma jet technique are presented. BST films were deposited on silicon coated with Pt/TiO2/SiO2 and on bare Si substrates. The nozzles-type RF hollow cathode has been fabricated from hot pressed BaTiO3, SrTiO3, and BST ceramics. Controlling of RF voltage, RF current and substrate temperature allowed us to deposit reproducible films with controlled grain size. Hysteresis loops, ellipsometric and micro-Raman investigation results are presented and discussed.