Analysis of Electron Transport Coefficients in SiH4 Gas Using Boltzmann Equation in the Presence of Applied Electric Field

Abstract

Monosilane (SiH4) plasma has numerous applications in plasma processing, transport coefficients are better to understanding and modeling of these gas discharge processes. The electron swarms in a monosilane gas under influence of uniform electric field can be calculated using two term approximation of Boltzmann equation for the range 1 ≤ E/N ≤ 1000 Td (1 Td= 1x10-17 V.cm2). The effective ionization coefficient's (α-η)/N and electron swarm parameters are calculated and compared with experimental and theoretical values of drift velocity, characteristic energy, mean electron energy and ionization coefficient. The critical field strength (E/N)cr.is calculated from the effective ionization curves. A set of electron molecule collisions has been assembled for monsilane gas which gave a good fit between the calculated and experimental values over the range of E/N investigated. The calculated distribution functions (EEDF) are found to be non-Maxwellian, having energy variations which reflect the important electron / molecule energy exchange processes. In addition, the percentages of energy lost by different types of elastic and inelastic collisions are given as a function of electric field strength E/N.

Keywords

• Swarm parameters EEDF Effective ionization coefficient. Plasmas Boltzmann equation