KINETICS OF FORMATION OF STRUCTURE DEFECTS IN A SURFACE-LAYER OF SILICON DURING THERMAL-OXIDATION

A study was made of the kinetics of formation and evolution of microdefects in a surface layer of silicon at the boundary with an oxide formed by thermal oxidation. The study was carried out as a function of the oxide thickness. Wafers of n-type Si:P with the phosphorus concentration N(P) = 5 X 10(16) cm-3 and the (111) orientation were oxidized in a vapor consisting of H2O + 4% HCl at 1000-degrees-C. The oxidation time was varied from 4 to 360 min. The nature and density of these microdefects on the surface of silicon under the oxide was examined visually in a metallographic microscope by etching in Sirtl's selective solution after previous removal of the SiO2 oxide by etching.