Kinetics of the decomposition of disilane on a silicon growth surface into two non-identical radicals

Abstract

Kinetic theory is used to treat the characteristics of the decomposition of the disilane molecule into two non-identical radicals in a wide range of growth temperatures and at low gas pressure in the reactor. The conditions for determining surface concentration are established and the possibility of the existence of an unambiguous relationship between the rates of decomposition $${v_{SI{H_3}}}$$ and $${v_{SI{H_4}}}$$ various fragments of the molecule is demonstrated. A strong dependence of the rate of decomposition of the molecules of the working gas on its pressure was revealed, which suggests that the film growth rate is mainly dependent on the rate and mode of the pyrolysis process on the surface of the growing layer. It is shown that a model of disilane decomposition into two non-identical fragments with the concurrent transfer of all the hydrogen atoms of the molecule onto the silicon growth surface is most preferrable for an adequate description of the pyrolysis process at temperatures within 400–800°C. Non-physical features of the temperature dependences of the kinetic coefficients appearing in the model of decomposition of disilane into two identical radicals is completely eliminated if the hydrogen atoms are transferred onto the growth surface at the chemisorption stage.