Influence of Cu Concentration on the Getter Efficiency of Dislocations and Oxygen Precipitates in Silicon Wafers

Abstract

Two getter tests were carried out in order to study the getter efficiency of oxygen precipitates in silicon samples contaminated with low and high Cu concentration. The samples were pre-treated by RTA followed by annealing in the temperature range between 700 °C and 1000 °C for various times in order to establish different concentrations and different sizes of oxygen precipitates in the samples. From the analysis of the results of the normalized inner surface and the gettering efficiency, it was deduced that in highly contaminated samples Cu precipitates more easily at dislocations than at the surface of oxygen precipitates. Contrarily, in the samples contaminated with low Cu concentration the presence of dislocations does not improve the getter efficiency. Cu precipitates were found at the edge of a plate-like precipitate in a sample with low Cu concentration.