Plasma diagnostics of hybrid magnetron sputtering and pulsed laser deposition J.G. Jones ⁎ , C. Muratore, A.R. Waite, A.A. Voevodin Air Force Research Laboratory, Materials and Manufacturing Directorate Wright-Patterson AFB, OH, 45433-7746, United States Available online 28 September 2006 Abstract This paper investigates the use of advanced triggering to synchronize a pulsed laser ablated plasma from a ceramic target with a pulsed DC sputtering plasma from a metal target for the purposes of depositing nanocomposite thin-films at low substrate temperatures. A digital oscilloscope and a programmable delay generator were used to prescribe the synchronization time of the two plasmas and frequency of discharge of the laser. Films were grown with different times of synchronization and subsequently characterized using X-ray diffraction and XPS. A multichannel analyzer was used to monitor the plasma emissions to determine spatial evolution of the synchronized pulsed plasma and a spectrometer was used to determine if additional spectra were generated through the interaction of the two plasmas. The studies did not show a clear presence of a new chemical compound formed in the hybrid plasma, but indicated an enhancement of the laser ablated plasma excitation in the presence of pulsed magnetron plasma process. This additional plasma excitation occurred at certain timing of the two pulsed plasma sources and was used to produce a Zr(Y)O 2 /Mo film containing crystalline ZrO 2 . Present results indicate that crystalline ceramic films can be deposited at low substrate temperature in which the film crystallinity is enhanced based on the synchronization timing. © 2006 Published by Elsevier B.V. Keywords: Magnetron sputtering; Pulsed laser deposition; Synchronization; Plasma; Film growth 1. Introduction Magnetron sputtering combined with pulsed laser deposition (MSPLD) forms a unique hybrid process in which a high energy laser capable of depositing oxide materials is combined with the efficient process of magnetron sputtering of metals for depositing low temperature tribological coatings, such as nanocomposites with multiple materials embedded in metal or ceramic matrix [1,2]. These nanocomposite coatings will ideally contain solid lubricants that can operate in different environments, with part of the nanocomposite being a phase of hard nanocrystalline structures that resist coating wear [3,4]. One of the challenges in preparing such composites is obtaining crystalline or nanocrystalline ceramic phases while trying to avoid excessive substrate temperatures that can deteriorate embedded solid dichalcogenide and carbon lubricants, cause grain growth of metallic lubricants, or soften the substrate material. In the interest of maintaining a low substrate temperature, such as below 300 °C, while still obtaining a required degree of ceramic phase crystallinity, the use of synchronization of the laser ablation plume with the pulsed DC magnetron sputtering process is investigated. In a typical MSPLD configuration, the laser ablation process is operated simultaneously without synchroniza- tion with the pulsed DC magnetron sputtering process [1,2]. For example, in the low temperature deposition of yttria stabilized zirconia (YSZ) and molybdenum (Mo) tribological coatings [5] the result is an amorphous film in which the metal content and oxide components can be adjusted based on the deposition conditions. Nanocrystallinity of YSZ phase at low substrate temperatures is required for improved abrasion wear resistance. The synchroniza- tion of the laser process with the sputtering process in this paper was applied to utilize a high energy of the laser plume for increased mobility of the deposited atoms at low substrate temperatures and promotion of crystalline phase growth. This synchronization was accomplished by configuring a digital oscilloscope to continuously monitor pulsed sputtering voltage and generate a digital reference signal for each transition from negative to positive voltage. Based on this time reference, a delay generator regulated time of the laser pulse in reference to the magnetron pulse throughout the deposition Surface & Coatings Technology 201 (2006) 4040 – 4045 www.elsevier.com/locate/surfcoat ⁎ Corresponding author. E-mail address: john.jones@wpafb.af.mil (J.G. Jones). 0257-8972/$ - see front matter © 2006 Published by Elsevier B.V. doi:10.1016/j.surfcoat.2006.08.096