Oxygen Concentration In Sputtering Gas Research Articles

Influence of oxygen concentration in sputtering gas on piezoelectric response of aluminum nitride thin films

The authors have investigated the influence of oxygen concentration in sputtering gas on the piezoelectric response of aluminum nitride (AlN) thin films prepared on silicon substrates. The piezoelectric response strongly depends on the oxygen concentration, and changes from +6.8to−7.0pC∕N with increasing oxygen concentration from 0% to 1.2%. The polar direction drastically inverts from the Al polarity to N polarity. When the oxygen concentration in sputtering gas was 1.2%, the oxygen concentration in the AlN films was 7at.%. Furthermore, the growth rate of the AlN films gradually decreases with increasing oxygen concentration in sputtering gas.

The metal–insulator transition induced in Bi 2Sr 1.93Cu 1.01O 6+ δ thin films by oxygen concentration in sputtering gas

Bi 2Sr 1.93Cu 1.01O 6+ δ thin films were deposited onto SiTiO 3 substrates by using DC magnetron sputtering. The structural characterization was carried out by X-ray diffraction. The effect of different oxygen pressures ( f O 2 ) in the sputtering gas on the electrical resistivity of thin films is presented. The value of sheet resistance per CuO 2 layer, R Q, is larger than the conventional quantum resistance, but is in agreement with the value estimated for 2D disordered systems. The log(1/ T) behaviour of ρ( T), in the region of the metal–insulator (MI) transition, is analyzed in a non-Fermi liquid model with a singular density of states in the presence of randomly distributed non-magnetic impurities.

Fabrication and magnetic properties of metal/cobalt ferrite composite thin films

To improve the saturation magnetization (Ms) of cobalt ferrite thin films, metal/cobalt ferrite composite thin films were prepared by controlling the sputtering conditions such as oxygen concentration in sputtering gas, substrate temperature, composition of the thin films. With decreasing the oxygen ratio from 50% to 5% in sputtering gas and increasing the substrate temperature from room temperature to 400 °C, the Ms of the thin films was increased and the coercivity (Hc) decreased. The result was attributed to deposition of the metal/cobalt ferrite thin films. With increasing the metal ratio in the thin films, preferred orientation of (111) of cobalt ferrite was worsened in the thin films. The metal deposited in the thin films was identified as cobalt with (002) preferred orientation. In higher cobalt content than the stoichiometric composition of CoFe2O4, the thin films with high Ms and Hc could be deposited in the wide substrate temperature range of 200–400 °C. We can prepare the metal/cobalt ferrite composite thin films with Ms about 580 emu/cm3 and Hc 1700 Oe by controlled the sputtering conditions. The thin films are thought to be applicable to the magnetic recording media with high recording density.

Preparation of Vanadium Oxide Thin Films by Radio-Frequency Magnetron Sputtering

Vanadium oxide thin films were prepared by the r.f. magnetron sputtering using vanadium metal powder as the target. The results are summarized as follows;(1) The deposition rate depended largely on the deposition parameters, such as sputtering power, gas pressure and oxygen concentration in the Ar-O2 gas atmosphere.(2) The films deposited at room temperature were amorphous. When the substrate temperatures were above 200°C, crystalline films were obtained.(3) With the increase of oxygen concentration in sputtering gas, the composition of thin films was transformed as follows: V→VO2→V4O9→V2O5.