Self-limiting and pattern dependent oxidation of silicon dots fabricated on silicon-on-insulator material

We present a systematic investigation of the oxidation properties of Si dot s fabricated on a silicon-on-insulator (SOI) wafer. Dots with diameters var ying from 9 to 81 nm were structured on a SOI wafer. These dots were oxidiz ed in a dry oxygen atmosphere at 700, 850, and 1000 degrees C. The resultin g structures were investigated using a side view transmission electron micr oscopy (TEM) technique in combination with energy filtered TEM. The dimensi ons of the residual Si and the grown SiO2 were then extracted from the micr ographs and analyzed. The oxidation appears to be retarded as compared to t he well-known planar oxidation. At 700 and 850 degrees C a self-limiting ef fect is observed as well as a clear pattern dependent oxidation at 850 and 1000 degrees C. We attribute these effects to stress buildup in the oxide. The critical stress, causing the self-limiting effect, is calculated using a model that considers the decrease of the reaction rate with increasing st ress perpendicular to the Si surface. (C) 2000 American Institute of Physic s. [S0021-8979(00)02402-6].