A solution of the doping problem for Ga delta-doping layers in Si

We have studied the incorporation of Ga in silicon during the fabrication of delta-doping layers. The delta-function doping profiles were grown by molecular beam deposition following a solid phase epitaxial growth method. Medium-energy ion scattering, secondary ion mass spectrometry, and Rutherford backscattering spectrometry were used to determine the structure and composition of the grown films. The interface velocity of the crystallization front and the diffusion coefficient of the impurity atoms in the Si matrix, both relevant parameters of the growth process, were measured. Optimum growth conditions were found that yield Ga doping profiles of less than 1.0 nm (full width at half maximum), with more than 95% of the buried dopant atoms on lattice sites. For these optimum growth conditions, a model is derived explaining the observed incorporation of the Ga atoms.