A simplified model for the vapor – Solid distribution of Silicon Germanium Chemical Vapor Deposition

Abstract

A simplified model of Silicon Germanium Chemical Vapor Deposition is proposed for the determination of Vapor – Solid distributions via any precursor route. The incorporation of the atomic element into the crystal lattice imposes to the chemical precursor the loss of all the ligands. Thus, dichlorosilane, silane, and disilane are discriminated on the basis of the amount of the atomic element brought into the equilibrium, instead of being different chemicals. Experimental trends show the ratio relative to silane is 2 for disilane and about ½ for dichlorosilane. The ratio relative to Si{100} is 0.59 for Si{110} and 0.82 for Si{111} for a growth via dichlorosilane and germane. Furthermore, Silicon Germanium alloy content is controlled by a thermodynamic equilibrium and the theoretical VS distribution is demonstrated for a growth via silane and germane. VS distribution of any chemistry onto any substrate orientation can therefore be estimated with the application of a straightforward corrective coefficient to a reference silane and germane chemistry.