Pulsed laser deposition of Nd:YAG on Si with substrate bias voltage Roman Rumianowski a,* , Franciszek Rozploch b , Roman S. Dygdala b , Slawomir Kulesza b , Przemyslaw Plo ´ciennik b , Andrzej Wojtowicz b a Warsaw University of Technology, Lukasiewicza 17, 09-400 Plock, Poland b Institute of Physics, Nicholas Copernicus University, Grudziadzka 5/7, 87-100 Torun, Poland Received 8 January 2001; accepted 21 April 2002 Abstract Polycrystalline yttrium aluminum garnet (Y 3 Al 5 O 12 ) thin films doped with neodymium have been prepared by the pulsed laser deposition (PLD) method on (1 1 1)-oriented Si wafers. Effect of external DC electrical field applied between substrate and target on the crystal quality was investigated. The growth process was carried out at a rather moderate substrate temperature of 500 8C. Obtained films were characterized by the X-ray diffraction (XRD) complete with radioluminescence spectroscopy (RLS). Intensive radioluminescence spectra of such films are reported for the first time. Laser-produced plasma plume investigations by means of time-of-flight (TOF) mass spectrometer were performed as well. Obtained results clearly indicate that the chemical composition of the plasma plume depends on the target–substrate bias voltage. # 2002 Elsevier Science B.V. All rights reserved. PACS: 07.75; 81.15.F Keywords: Plasma processing; Epitaxy; Growth 1. Introduction Studies of neodymium-doped thin films of YAG focus much interest due to their technological appli- cations in optoelectronic systems. Growth of the doped material is found to be much more difficult than the undoped one because of the fact that doping with Nd 3þ ions decreases stability of the fourfold coordination of aluminum within the YAG lattice. Polycrystalline Nd-doped Y 3 Al 5 O 12 ceramics show highly efficient laser oscillations at 1064 nm bringing an alternative to Nd:YAG single crystals [1]. Several deposition techniques were employed to deposit Nd:YAG thin films, but only a few publications on pulsed laser deposition (PLD) of YAG have been reported [2,3]. Another optical thin garnet films were also successfully fabricated by PLD [4–8]. Presented paper deals with experimental investigation of the post-plasma plume and the quality of the deposited layer, which were influenced by external electric field. The technique of the plume characterization is based on the time-of-flight (TOF) spectroscopy. In order to understand physical processes in such a plume, TOF spectra are measured at different experimental condi- tions. Then, they are analyzed in terms of the chemical Applied Surface Science 193 (2002) 261–267 * Corresponding author. Fax: þ48-24-262-7494. E-mail address: arrum@poczta.onet.pl (R. Rumianowski). 0169-4332/02/$ – see front matter # 2002 Elsevier Science B.V. All rights reserved. PII:S0169-4332(02)00488-9