Characteristics of the material improvement process for silicon on sapphire by solid phase epitaxial regrowth

Abstract

A comprehensive matrix study of the material modification of chemical vapor deposited silicon on sapphire has been made. The modification is effected by applying twice the process of ion implantation with 28 Si+ ions followed by solid phase epitaxial regrowth (SPEG) induced by furnace annealing. The matrix consisted of varying the fluences for the first and second implantation from just above the critical fluence for forming an amorphous phase to 7×1015cm−2. The defect reduction was studied for each sample of the matrix. This study has shown that the density of defects at the silicon/sapphire interface and silicon surface depends on both implantations. The deposited damage energy peak position is estimated to occur at a depth ∼Rp for a substrate temperature of 330 K during implantation. The position of the damage peak affects the estimated damage at the silicon sapphire interface which controls the aluminum outdiffusion. The major reduction in the defect density has already occurred for fluences of the two implantations such that the amorphous regions terminate within about 200 Å of each other. Using the width of the random yield portion of the channeled spectra for MeV 3He+ ions overestimates the width of the amorphous layer.