Effects of stress on solid-phase epitaxial regrowth and corner defect generation in As+-implanted, two-dimensional amorphized Si

Abstract

The effect of stress induced by chemical vapor deposited SiO2 films on the solid-phase epitaxial regrowth and the corner defect generation in As (+)-implanted, two-dimensional amorphized Si has been studied. A trench structure was used to form the two-dimensional amorphous layer and to induce the stress in the Si substrate. As implantation with an energy of 80 keV and a dose of 3 x 10(15)/cm(2) completely amorphized a 100-nm-thick silicon surface layer under the trench bottom and produced a curved amorphous/crystalline interface under the bottom corner of the trench. The stress level in the chemical vapor deposited SiO2 films was varied by using different deposition techniques. It was found that, in the sample with a high-tensile stressed chemical vapor deposited SiO2 film as a trench fill, a notch was formed in the amorphous/crystalline interface after annealing at 500 degreesC for 4 h and microtwins were formed on {1 1 1} planes after annealing at 650 degreesC for 60 min under the bottom corner of the trench. The notch formation and the corner defect generation were explained by the effect of the shear stress induced by the chemical vapor deposited SiO2, films on the activation barrier of solid-phase epitaxial regrowth. (C) 2001 Published by Elsevier Science B.V.