L. Teulé-Gay

Study of the transport of titanium neutrals and ions in the post-discharge of a high power pulsed magnetron sputtering device

This paper deals with the diagnostics of a high power pulsed magnetron sputtering device (HPPMS). The HPPMS plasma was spatially and temporally characterized in the post-discharge using optical absorption spectroscopy and Langmuir probe time resolved measurements. A circular titanium target was used, the buffer gas was argon and the pressure was fixed at 4 Pa. The titanium densities (neutrals and ions) were measured by a pulsed resonant absorption spectroscopy technique. We found an ionization degree higher than 0.5. Comparison beetween the experimental results and a simple one-dimensional model of diffusion shows that in these conditions, the transport of neutral and ionized sputtered atoms is mainly controlled by diffusion (ambipolar diffusion for ions).

Determination of titanium temperature and density in a magnetron vapor sputtering device assisted by two microwave coaxial excitation systems

We present an optical absorption diagnostic technique devoted to the simultaneous determination of titanium density and temperature during sputtering of Ti. These measurements were performed in a type of ionized physical vapor deposition reactor, consisting of a magnetron sputtering device assisted by two microwave systems for the ionization of the sputtered vapor of the magnetron. Our goal is to optimize the ionization in this reactor in order to improve the deposition process (film quality, recovery of the layers, etc.) compared to standard magnetron sputtering systems. In order to determine both titanium neutral and ion densities, we have used a titanium hollow cathode vapor lamp powered with pulsed power supply. Measurements were carried out at different positions in the reactor at different pressures (1–15 Pa). We have studied the effect of magnetron current from 100 mA to 2 A and of microwave power from 100 W to 1 kW. At lower pressures, we have shown that the titanium is not thermalized close to th...

New type of plasma reactor for thin film deposition: magnetron plasma process assisted by microwaves to ionise sputtered vapour

Abstract A new type of plasma reactor for thin film deposition has been designed: a magnetron-sputtering device assisted by microwave applicators to ionise the sputtered vapour of the magnetron. Ionizing the vapour has several advantages: improvement of the film quality, deposition on substrates with complex shapes, enhancement and control of the reactivity. The reactor consists of a planar rectangular magnetron cathode (22 cm×9 cm) and of two coaxial-type microwave applicators located perpendicularly to the substrate–magnetron axis, on both sides of the sputtered vapour flow. This reactor can operate on a wide pressure range: from 0.2 to 60 Pa. Several in-situ diagnostics have been performed to characterise the process in argon gas with chromium and titanium targets. Electron density of the order of 10 11 –10 12 cm −3 and electron temperature of 1.5–2 eV were measured in the microwave plasma by a cylindrical Langmuir probe; emission of metallic ions (Cr + , Ti + ) was clearly identified when the microwave plasma is turned on; concentration of Cr or Ti atoms was measured by absorption spectroscopy, a decrease of this concentration is observed when the microwave power is increased. Characterisation of thin titanium films was performed ex-situ by Rutherford backscattering spectroscopy (RBS) for Ti content and nuclear reaction analysis (NRA) for oxygen contamination. Film density was deduced from RBS and NRA measurements and X-ray reflectometry. Oxygen contamination in the film is clearly decreased when microwave plasma is turned on and with a bias applied to the substrate.

Spatial characterization of an IPVD reactor : neutral gas temperature and interpretation of optical spectroscopy measurements

This paper deals with the characterization of an ionized physical vapour deposition (IPVD) reactor using an additional microwave plasma. The IPVD reactor was spatially characterized using optical emission spectroscopy, optical absorption spectroscopy and Langmuir probe measurements. A rectangular titanium target was used, the buffer gas was argon and the pressure was fixed at 4 Pa. The influence of the microwave power (between 0 and 900 W) and the magnetron discharge current (0.5 and 2 A) on the densities of the titanium species (neutral and ionic), argon emission line intensity and titanium and argon temperature variations was investigated. The titanium temperature and densities were measured using the pulsed resonant absorption spectroscopy technique. The neutral and ion fluxes on the substrate were deduced from these measurements. It was found that the ratio (Ti+)/(Tin) increases by a factor of 30 when additional microwave plasma is used. Moreover, we point out the temperature as a key parameter in plasma diagnostic interpretations.

Recent Developments on Ionized Physical Vapour Deposition: Concepts, Determination of the Ionisation Efficiency and Improvement of Deposited Films

While most of the IPVD reactors use radio-frequency (RF) coils to create additional ionization, we developed an alternative technique consisting of a home made magnetron sputtering device in which the ionization of the emitted sputtered vapor is achieved by two microwave antennas. Langmuir probe measurements were used to determine electronic density and temperature. Emission optical spectroscopy has been performed and argon and titanium line intensities have been measured, showing an increase of Ti+* to Ti* line intensity ratio. Optical absorption spectroscopy using a titanium hollow cathode lamp powered with a pulsed power supply has also been performed to determine the ionized fraction of the sputtered vapor. Preliminary results are also given for a conventional IPVD system (with RF loops) used for the deposition of Ti-based biomaterials.