In-Situ Optical Emission Spectra of Ti, TiN and TiSi 2 Plasma During Thin Film Growth by Pulsed Laser Evaporation
- PDF / 240,446 Bytes
- 5 Pages / 420.48 x 639 pts Page_size
- 59 Downloads / 201 Views
IN-SITU OPTICAL EMISSION SPECTRA OF Ti, TiN AND TiSi 2 PLASMA DURING THIN FILM GROWTH BY PULSED LASER EVAPORATION S. Pramanick and J. Narayan Department of Materials Science and Engineering, North Carolina State University, Raleigh NC 27695.
ABSTRACT The first optical emission spectra of Ti, TiN and TiSi2 plasma during growth of thin films by pulsed laser evaporation has been reported. A KrF excimer laser (248nm) with pulsewidth of 45ns operating on 5Hz repitition rate was used for deposition of refractory metal thin films using varying laser fluence of 4J/cm 2 to 15J/cm 2 . Most of the radiative species seen in plasma belongs to atomic neutrals and ionic species such as Ti I, Ti II, Si I, Si II and N 11. Emission spectra was mostly dominated by neutral and ionic emission from Titanium (Ti I and Ti II).
INTRODUCTION Pulsed laser evaporation (PLE) has emerged as the dominant technique for growth of stoichiometric thin films because it has produced high Tc superconducting thin films of better quality than those obtained by all other deposition technique [1,2]. In the last few years, PLE has been used, increasingly, for the deposition of compound thin films such as TiN, TiSi2, CoSi2, BaTiO3, PbTiO3 etc. [3,4]. Lately much of efforts in our group has been devoted to the growth of TiN, TiSi2, CoSi2 thin films. In ULSI processing, silicides are increasingly being used for S/D contact metallization and local interconnects for polysilicon gate with TiN acting as a diffusion barrier. PLE has the advantage of producing silicides [4] and TiN films with a very sharp interface [3], which is essential for low junction leakage of submicron MOSFET. The deposition mechanism involved in PLE is not very well understood. Most of the experimental and theoretical research by groups working in this field has been devoted to understand the mechanism involved in YBCO high Tc superconducting thin film growth [5,6,7]. In PLE, the physical processes of thin film deposition can be divided into three regimes: 1) interaction of laser beam with bulk target, 2) initial isothermal expansion, and 3) adiabatic expansion of HT-HP plasma leading to the thin film deposition [5]. It has been now known that the YBCO and PrBCO plasmas consists of two components : 1) neutral and ionic atomic beams with a high velocity component, and 2) a low velocity component involving molecular species [6]. This has been independently confirmed by optical emission spectroscopy [6] and quadropole mass spectroscopy [8]. We have studied the optical emission from laser produced plasma of Ti, TiN and TiSi2 during thin film growth to understand the nature of growth by PLE and of the species present in these plasmas. It will be of practical importance to be able to relate the quality of thin film growth with the species present and with the complex transport processes invol-,ed in plasma plume.
Mat. Res. Soc. Symp. Proc. Vol. 250. ©1992 Materials Research Society
126
EXPERIMENTAL FIBEROPTIC CABLE
MULTIPLE TARGET HOLDER
Figure I. Schematic diagram for pulsed laser deposit
Data Loading...
