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Keywords:

  • Copper cyclopentadienyltriethylphosphine;
  • Copper film;
  • Gas-phase monitoring;
  • Mass spectrometry;
  • MOCVD;
  • Thermal decomposition

Abstract

Application of mass spectrometry (MS) for the investigation of metal-organic (MO)CVD processes is demonstrated through the example of the deposition of copper films from copper(I) cyclopentadienyltriethylphosphine (CpCuPEt3). In-situ MS, where a miniature hot-wall CVD reactor built in the time-of-flight mass analyzer, is used to investigate the decomposition mechanism of the precursor during low-pressure (LP) MOCVD. On line MS is used to explore the gas phase upon copper film production as a function of temperature in a cold-wall MOCVD reactor operating under 10 Torr. The two MS techniques provide compatible information which illustrates the vapor behavior of the precursors on the growing surface, and correlates all changes in the composition of the gas phase with the growth rate of Cu films in any stage of the deposition process. In agreement with reported experimental results, a monotonic increase in the intensity of the precursor and a decrease in the intensity of the products are observed with deposition time at low deposition temperature, indicating a gradual decrease in the growth rate. This behavior is attributed to the saturation of the growing surface with adsorbed triethylphosphine which hinders precursor supply to the deposition zone. It is shown, through the example of the co-deposition of Al-Cu films from dimethylamine alane and CpCuPEt3, that there is no mutual interaction of the precursors in the gas phase.