Integral stress in ion-implanted silicon

A theoretical model of production and relaxation of stress in ion-implanted silicon is proposed. It is based on the assumptions that the point defects are the source of mechanical stress and that the relaxation of stress is due to the viscous flow of ion-irradiated silicon. The integrated stress acting in a damaged layer has been studied as a function of the Ar+-ion current density j=0.01-1 μA cm-2, ion energy E0=40-160 keV, substrate temperature T=78-500 K and dose in the range up to 1016 Ar+ cm-2. It was shown that the maximum integral stress values induced in silicon are of the order of 100 N m-1. The maximum is reached at a dose of about 1014 Ar4 cm-2 that corresponds to the silicon-amorphization dose. Stress due to implanted ions is essential for the high-dose region (>1015 Ar+ cm-2) and it dominates at high temperatures of the substrate. (author)