Abstract. Mathematical solutions to the diffusion equation are considered for the case in which the diffusion coefficient varies as some power of the concentration, i.e. D=kCⁿ. For the 'constant source' set of boundary conditions, explicit solutions can be found using a self-similar technique; for the 'infinite source' set of conditions, approximate solutions can be found. They agree very well with previously published calculations using relatively laborious numerical techniques. A procedure is described whereby the errors involved in the approximation can be determined. Diffusion coefficients of the form D=kCⁿ are important in semiconductor diffusion. The diffusion of zinc in GaAs is taken as an example and theoretical profiles are plotted. Their agreement with experimentally determined profiles is discussed.

Print publication: Issue 11 (1 August 1976)