Low-energy electron interactions with chlorotrimethylsilane (Si(CH3)3Cl), dichlorodimethylsilane (Si(CH3)2Cl2) and chloromethyldimethylsilane (SiH(CH3)2(CH2Cl))

Rationale Silane derivatives are widely used in industrial plasmas for manufacturing lighting devices, solar cells, displays, etc. Models of technological plasmas require quantitative data. The rate coefficients (k) and the activation energies (E-a) of thermal electron attachment for chlorotrimethylsilane (Si(CH3)(3)Cl), dichlorodimethylsilane (Si(CH3)(2)Cl-2) and chloromethyldimethylsilane (SiH(CH3)(2)(CH2Cl)) are reported. This is important for understanding the basic processes occurring in plasmas. Methods The pulsed Townsend technique (known as the electron swarm method) has been applied for the measurements. In this technique, electrons generated by a laser, under a uniform electric field, traverse to an anode and induce a charge on it. In the buffer gas charge grows linearly, but in the presence of a scavenger, electrons are captured, and thus the rate of charge increase slows down with time. From the shape of the pulse, the kinetic parameters are determined. Results Kinetic parameters from the study of thermal electron attachment by Si(CH3)(3)Cl, Si(CH3)(2)Cl-2 and SiH(CH3)(2)(CH2Cl) were determined for the first time. The corresponding rate coefficients at 298 K are equal to (9.56 +/- 0.02) x 10(-11), (6.62 +/- 0.02) x 10(-11) and (1.24 +/- 0.05) x 10(-11) cm(3) s(-1) and E-a values are equal to 0.29 +/- 0.01, 0.24 +/- 0.01 and 0.31 +/- 0.01 eV for Si(CH3)(3)Cl, Si(CH3)(2)Cl-2 and SiH(CH3)(2)(CH2Cl), respectively. The experiment was performed in the 298-378 K temperature range. Conclusions The presented results provide important new information about fundamental quantities such as rate coefficients and activation energies for thermal electron capture by chlorinated derivatives of silane. These data can further advance our understanding of thermal electron interactions with chlorosilanes that can be used to control the important species in the plasmas of many modern technologies.