Pierre-Yves Jouan

Impact of magnetron configuration on plasma and film properties of sputtered aluminum nitride thin films

We have investigated the growth of the c-axis oriented aluminum nitride (AlN) thin films on (100) silicon by reactive dc magnetron sputtering at low temperature, considering the effect of the magnet configuration on plasma and film properties. It appears that a magnet modification can significantly modify both the plasma characteristics and the film properties. Electrical and optical characterizations of the plasma phase highlight that depending on the magnet configuration, two very different types of deposition process can be involved in the same deposition chamber. On the one hand, with a balanced magnetron (type 1), the deposition process enhances the production of AlN dimers in the plasma phase and enables to synthesize AlN films with different preferential orientations (100, 002, and even 101). On the other hand, a strongly unbalanced magnetron (type 2) provides a limited production of AlN species in the plasma phase and a strong increase in the ratio of ions to metal atom flux on the growing films. ...

HiPIMS Ion Energy Distribution Measurements in Reactive Mode

In this paper, mass spectrometry was used to measure the ion energy distributions of the main species during the sputtering of an aluminum target in a reactive Ar + N2 mixture. Both conventional magnetron sputtering (dc) and high-power impulse magnetron sputtering (HiPIMS) were used. It appears that, in the HiPIMS, N+ and Al+ ions are significantly more energetic (up to 70 eV) than in the dc (<;40 eV). Furthermore, the HiPIMS Al+ signal is two orders of magnitude greater than in the dc, and time-resolved measurements indicate that most of the ion flux hits the substrate during the OFF time of the impulse sequence.

Epitaxial growth of aluminum nitride on AlGaN by reactive sputtering at low temperature

We report the synthesis of 1μm thick single crystalline aluminum nitride films by dc magnetron sputtering on AlGaN∕GaN layer grown on sapphire substrate at low temperature (substrate temperature <250°C). The microstructure of c-axis oriented AlN films deposited on Si (100) and AlGaN ⟨0001⟩ substrates was studied by x-ray diffraction, selected area electron diffraction, and transmission electron microscopy. The optimization of process parameters, involving low energetic ion bombardment on film surface (20–30eV) during the growth, leads to an increase in the surface mobility and thus promotes AlN epitaxial growth on AlGaN substrate at 250°C.

Process- and optoelectronic-control of NiOx thin films deposited by reactive high power impulse magnetron sputtering

In this contribution, based on the analyses of the discharge behavior as well as final properties of the deposited Ni-O films during reactive high power impulse magnetron sputtering discharge, we have demonstrated that monitoring the oxygen flow rate leads to 4 different regimes of discharge. Tuning the oxygen partial pressure allows deposition of a large range of chemical compositions from pure nickel to nickel-deficient NiOx (x > 1) in the poisoned mode. Investigation of the plasma dynamics by time-resolved optical emission spectroscopy suggests that the discharge behavior in the poisoned mode principally comes from the higher contribution of both oxygen and argon ions in the total ionic current, leading to a change in the ion induced secondary electron emission coefficient. Additionally, material characterizations have revealed that optoelectronic properties of NiOx films can be easily tuned by adjusting the O/Ni ratio, which is influenced by the change of the oxygen flow rate. Stoichiometric NiO films...