EFFECT OF INTERSTITIAL OXYGEN ON FORMATION OF AMORPHOUS SIOX LAYER INDIRECTLY BONDED CZOCHRALSKI SILICON-WAFERS

We have investigated the effect of interstitial oxygen in CZ silicon w afers on the formation of the amorphous SiO(x) layer (x = 0.2-0.3 afte r annealing at 1100-degrees-C for 2 h) at the interface in directly bo nded silicon wafers using high-resolution transmission electron micros copy (HR-TEM) and energy dispersive X-ray (EDX). As the annealing time became longer, the thickness and the oxygen concentration in this lay er increased, depending on the concentration of interstitial oxygen in wafers. These changes are caused by the diffusion of oxygen atoms fro m the bulk toward the bonded interface. However, they must not play su ch an important role in the initial stage of the formation of this lay er because the layer existed discontinuously and was not affected by r otational misorientation or the microroughness.