The growth mechanism of SiO₂ thin film on Si(100) and Si(111) by ozone was investigated using various surface/interface analytical techniques such as XPS, STM, AFM, SHG (Second Harmonic Generator), and MEIS (Medium E nergy Ion Scattering spectroscopy). Two different ozone generators were fabricated and used for the investigation. The first ozone generator, which was used for the study of the initial oxidation, supplies low pressure (<10^-2 Pa) and high purity (>80%) ozone gas by vaporization of pure liquid ozone at low temperature (< 100 K). The second ozone generator, used mainly for the oxide film growth, supplies high pressure (1 atm) ozone gas with concentration <30% by desorbing ozone adsorbed on silica-gel.

Through the comparison of ozone oxidation to the oxidation with molecular oxygen, followings were made clear. i) Atomic oxygen dissociated from ozone molecules at Si surface directly attacks backbond of Si, hence it can oxidize hydrogen -terminated Si which oxygen molecules can not. ii) Formation of suboxide at the SiO₂/Si interface is suppressed, leading to stable Si-O-Si network formation even at low pressure and low temperature condition. iii) The oxide thin film growth proceeds in layer-by-layer manner, and the interface keeps the original step/terrace structures at the interface after the growth of about 1 nm thick oxide film. In addition to these features, the existence of no (or very thin) structural transition layers was suggested for the ozone oxide film by the MEIS experiments and the etching experiment with dilute HF solution, while those experiments for thermally grown oxide showed the existence of the transition layers with thickness about 1 nm. Based on these results, the superior features and growth mechanism of SiO₂ by ozone will be discussed.

The system for plasma enhanced chemical vapour deposition of TiN and (TiAl)N hard coatings was studied by means of the Langmuir probe technique to obtain better control of the film growth. Two planar reactors with showerhead grounded electrode and powered substrate holder were used for this study. The substrate were heated up to 500° C. A negative pulses were applied to the substrate holder. A mixture of argon, hydrogen and nitrogen and tinaniumtetrachlorid and/or aluminumtrichlorid were used as the working gas. The electron density, electron temperature and plasma potential were investigated in dependence on the pressure, power, reactor temperature and working gas composition. It has been found that both the plasma potential and the electron density decreased with pressure and this tendency was independent of the composition of the working gas. The highest value of the electron density was 2.0x10¹⁶m^-3 at 1.5mbar and this value decreased to 6.9x10¹⁵m^-3 at 2.5 mbar. Simultaneously a drop of the plasma potential from 0 V at 1.5 mbar down to -23V at 2.5mbar was observed. Addition of the reactive gas caused a further decrease of the plasma potential under -50V. The rise in the reactor temperature resulted in an enhancement of the plasma potential. The plasma potential changed from -29V at 120°C up to -0.7V at 410°C with simultaneous increase in the electron density from 5.7x10¹⁵m^-3 up to 3.5x10¹⁶m^-3. The measurements during the deposition process indicate very good stability of the plasma used for the deposition of (TiAl)N whereas some instability occurs during deposition of TiN. A significant difference in the ion current of about a factor 8 between particular positions indicated different gas composition at various positions in the reactor. This corresponded with different Ti/Al ration found in films deposited at various positions on the substrate holder.

One of us, Petr Spatenka, acknowledges financial support by the Grant Agency of Czech Republic, Grant No. 202/98/0116.

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1 A. J. Steckl, J. Devrajan, S. Tlali, H. E. Jackson, C. Tran, S. N. Gorin and L. M. Ivanova, Appl. Phys. Lett. 69 (1996) 3824.

Silver Indium Telluride (AgInTe₂) films have been grown by Hot Wall Epitaxy (HWE) technique onto the KCl substrate kept at different temperatures in vacuum of 1x10^-5 torr. The experimental conditions are optimised to obtain better crystallinity of the films. Besides Scanning and Transmission electron microscopy, the electrical conductivity, Hall mobility and carrier concentration as a function of temperature are investigated.

Observations reveal that the electrical conductivity of films increases with the increase in temperature and show higher mobility when compared to those prepared on glass substrate. The films appear to be p-type; thus, indicating holes as dominant charge carrier. Results on electron microscopy indicate that HWE grown AgInTe₂ films show comparatively better crystallinity and crystallite size increases with the increase in substrate temperature.