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Baesweiler, Germany

Hempel F.,INP Greifswald | Lang N.,INP Greifswald | Zimmermann H.,INP Greifswald | Stramke S.,ELTRO GmbH | Ropcke J.,INP Greifswald
Measurement Science and Technology | Year: 2010

Boron trichloride (BCl3) is used as a source gas in various industrial plasma applications. The online monitoring of its ground state concentration in the plasma process reactor is vital for improved insight into the plasma chemistry and to increase productivity, reliability and reproducibility of the process. Infrared absorption spectroscopy was applied for in situmeasurements of absolute densities of BCl3 and HCl in planar microwave plasma sources as well as in an industrial pulsed dc discharge reactor. In this paper procedures for the determination of HITRAN format line strength data files for BCl3 are described together with results of concentration measurements. The results show the influence of the discharge parameters on the dissociation of BCl3 and its conversion to HCl. Observations using tuneable diode lasers are compared with measurements using quantum cascade lasers and the applicability of this diagnostic technique for industrial plasma process monitoring is shown. © 2010 IOP Publishing Ltd.

Lang N.,INP Greifswald | Hempel F.,INP Greifswald | Stramke S.,ELTRO GmbH | Ropcke J.,INP Greifswald
Japanese Journal of Applied Physics | Year: 2011

In situ measurements are reported giving insight into the plasma chemical conversion of the precursor BCl3 in industrial applications of boriding plasmas. For the online monitoring of its ground state concentration, quantum cascade laser absorption spectroscopy (QCLAS) in the mid-infrared spectral range was applied in a plasma assisted chemical vapor deposition (PACVD) reactor. A compact quantum cascade laser measurement and control system (Q-MACS) was developed to allow a flexible and completely dust-sealed optical coupling to the reactor chamber of an industrial plasma surface modification system. The process under the study was a pulsed DC plasma with periodically injected BCl3 at 200 Pa. A synchronization of the Q-MACS with the process control unit enabled an insight into individual process cycles with a sensitivity of 10-6cm-1· Hz-1/2. Different fragmentation rates of the precursor were found during an individual process cycle. The detected BCl3 concentrations were in the order of 1014 molecules-cm-3. The reported results of in situ monitoring with QCLAS demonstrate the potential for effective optimization procedures in industrial PACVD processes. © 2011 The Japan Society of Applied Physics.

Hamann S.,INP Greifswald | Borner K.,TU Bergakademie Freiberg | Burlacov I.,TU Bergakademie Freiberg | Spies H.-J.,TU Bergakademie Freiberg | And 3 more authors.
Review of Scientific Instruments | Year: 2015

A laboratory scale plasma nitriding monitoring reactor (PLANIMOR) has been designed to study the basics of active screen plasma nitriding (ASPN) processes. PLANIMOR consists of a tube reactor vessel, made of borosilicate glass, enabling optical emission spectroscopy (OES) and infrared absorption spectroscopy. The linear setup of the electrode system of the reactor has the advantages to apply the diagnostic approaches on each part of the plasma process, separately. Furthermore, possible changes of the electrical field and of the heat generation, as they could appear in down-scaled cylindrical ASPN reactors, are avoided. PLANIMOR has been used for the nitriding of steel samples, achieving similar results as in an industrial scale ASPN reactor. A compact spectrometer using an external cavity quantum cascade laser combined with an optical multi-pass cell has been applied for the detection of molecular reaction products. This allowed the determination of the concentrations of four stable molecular species (CH4, C2H2, HCN, and NH3). With the help of OES, the rotational temperature of the screen plasma could be determined. © 2015 AIP Publishing LLC.

Huchel U.,ELTRO GmbH | Stramke S.,ELTRO GmbH | Stramke M.,ELTRO GmbH
HTM - Journal of Heat Treatment and Materials | Year: 2015

The constant, stable and high product and process stability and the competitiveness on world market level are base requirements on all modern production processes. Nitriding increases the resistance against wear and corrosion properties and improves strength. Negligible shape changes and corrigible dimensional changes make it possible, that nitrided parts can be used without additional machining. So the advantages of nitrided layers are used in more and more applications. Beside quality aspects costs decide which treatment will be used. Based on a process analysis the article shows how costs and quality can be influenced in plasma nitriding processes. © Carl Hanser Verlag GmbH & Co. KG.

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