Chemical Vapour Deposition of Copper on Si(111) and SiO sub 2 Substrates

• Published in: Journal of crystal growth 1992-06, Vol.121 (1-2), p.223-234
• Main Authors: Lampe-Onnerud, C, Jansson, U, Harsta, A, Carlsson, J-O
• Format: Article
• Language: English
• ISSN: 0022-0248

Chemical vapour deposition of Cu and Cu sub 3 Si using solid CuCl as the Cu source has been investigated. It ws found that the evaporation of CuCl from the solid powder was a critical step in the process. The evaporation rate, and hence the partial pressure of CuCl, was dependent mainly on two factors: (i) deviation from equilibrium evaporation and (ii) formation of oxygen-containing compounds on the powder surface. The potential use of CuCl as a Cu source in CVD was demonstrated for three substrate conditions: SiO sub 2 , Si(111) and patterned Si(1211)/SiO sub 2 wafers. For SiO sub 2 , thin Cu films (resistivity 3.3 mu Omega cm) were deposited at 500 deg C from a CuCl/H sub 2 /Ar gas mixture. For Si(111) substrates, Cu sub 3 Si was invariably formed in the temperature range 350-500 deg C using either a CuCl/Ar or a CuCl/H sub 2 /Ar gas mixture. The Cu sub 3 Si phase showed a strong epitaxial relationship with the Si(111) substrates, especially at higher deposition temperatures. At lower deposition temperatures or with H sub 2 present in the vapour, elemental Cu in the form of particles was formed on top of the Cu sub 3 Si layer. The selectivity of the CuCl process was demonstrated on a patterned Si(111)/SiO sub 2 substrate. Finally, rather high Cl concentrations were detected on the surface of the films, indicating that the desorption of Cl-containing molecules may play an important role in the deposition process.