Some Observations on Oxygen Precipitation/Gettering in Device Processed Czochralski Silicon

Abstract

Several results of our experimental program studying the relationship between the properties of the silicon starting material and N‐channel MOS dynamic RAM circuit performance is described. The thermal history and oxygen and carbon concentrations control the silicon material properties and much of the subsequent circuit performance. The beneficial effect of intrinsic gettering due to precipitation of oxygen in the bulk on MOS dynamic RAM refresh performance will be shown. Equivalent thermal processes will result in similar circuit performance only when the silicon material is equivalent. Some circumstantial evidence is also presented for a degrading effect of high concentrations of carbon in the starting material.