Investigations on the correlation between growth rate and gate oxide integrity of Czochralski-grown silicon

Abstract

Czochralski-grown silicon crystals show two concentric regions providing gate oxide layers of markedly different breakdown stability. The two regions are separated by a “wreath”, several millimeters in width, that is built-up from microdefects which act as nucleation centres for the formation of oxidation induced stacking faults. The core region of inferior gate oxide integrity (GOI) becomes smaller in diameter with decreasing pulling speed. The three regions have been extensively characterized by numerous analytical techniques. The most striking difference between the inner and outer regions, besides the GOI, is the enhanced oxygen precipitation in the core region occurring after annealing. An attempt is undertaken to analyze the defect structure in the different regions, its origin, correlation with growth and annealing processes, and its effect on the GOI.