INTEGRAL STRESS IN ION-IMPLANTED SILICON

A theoretical model of production and relaxation of stress in ion-impl anted silicon is proposed. It is based on the assumptions that the poi nt defects are the source of mechanical stress and that the relaxation of stress is due to the viscous flow of ion-irradiated silicon. The i ntegrated stress acting in a damaged layer has been studied as a funct ion of the Ar+-ion current density j = 0.01-1 mu A cm(-2), ion energy E-0 = 40-160 keV, substrate temperature T = 78-500 K and dose in the r ange up to 10(16) Ar+ cm(-2). It was shown that the maximum integral s tress values induced in silicon are of the order of 100 N m(-1). The m aximum is reached at a dose of about 10(14) Ar+ cm(-2) that correspond s to the silicon-amorphization dose. Stress due to implanted ions is e ssential for the high-dose region (>10(15) Ar+ cm(-2)) and it dominate s at high temperatures of the substrate.