Kinetics of SiHCl3 thermal decomposition based on Cl and Si atom measurements

Cl and Si concentration measurements were performed in highly diluted SiHCl3/Ar mixtures. The reflected shock method in combination with sensitive atomic resonance absorption spectroscopy was applied. In the literature, the initial decomposition step of SiHCl3 has been suggested to be SiHCl3 reversible arrow (k1) SiCl2 + HCl (R1) but this has not yet been established. At 1730 K less than or equal to T less than or equal to 3300 K, 0.8 bar less than or equal to p less than or equal to 4.0 bar, and mixtures of 0.5 to 5 ppm SiHCl3 in argon, a strongly temperature-dependent formation of Cl atoms was observed. The signals were evaluated in terms of the rate coefficient k(2): SiCl2 + M reversible arrow (k2) SiCl+ Cl+ M (R2) k(2) = 5.4(-2.3)(+3.8) x 10(15) exp[-(39,300 +/- 1200)K/T] cm(3) mol(-1) s(-1) Si2H6 is known to be a rapid silicon source at T greater than or equal to 1550 K. In highly diluted Si2H6/Ar mixtures, a very fast consumption of the initial Si atom concentrations was measured when a few parts per million SiHCl3 was added. The signals obtained at 1570 K less than or equal to T less than or equal to 2030 K and p = 1.7 bar were kinetically analyzed and assigned to the reaction of Si atoms with SiCl2. Si + SiCl2 reversible arrow (k4) products (R4) k(4) = 5.6 +/- 0.97 +/- 10(14) cm(3) mol(-1) s(-1) All results were verified and discussed based on computer simulations.