PROCESS FOR THE PREPARATION OF SILICON WAFERS HAVING A CONTROLLED DISTRIBUTION OF OXYGEN PRECIPITATE NUCLEATION CENTERS

摘要

A PROCESS FOR THE PREPARATION OF SILICON WAFERS HAVING A NON-UNIFORM DISTRIBUTION OF A OXYGEN PRECIPITATE NUCLEATION CENTERS. SILICON WAFERS HAVING A CONTROLLED DISTRIBUTION OF OXYGEN PRECIPITATE NUCLEATION CENTERS ARE PREPARED BY HEATING THE WAFER IN A MANNER TO CREATE A TEMPERATURE GRADIENT ACROSS THE THICKNESS OF THE WAFER FOR A PERIOD OF TIME. UPON A SUBSEQUENT OXYGEN PRECIPITATION HEAT TREATMENT, THOSE REGIONS OF THE WAFER WHICH WERE RAPIDLY HEATED TO A TEMPERATURE IN EXCESS OF ABOUT 900 °C WILL FORM A DENUDED ZONE WHEREAS THOSE REGIONS OF THE WAFER WHICH DID NOT ACHIEVE A TEMPERATURE IN EXCESS OF ABOUT 900 °C DURING THE RAPID HEATING WILL FORM OXYGEN PRECIPITATES.