THE EFFECT OF HYDROGEN ANNEALING ON OXYGEN PRECIPITATION BEHAVIOR ANDGATE OXIDE INTEGRITY IN CZOCHRALSKI SI WAFERS

We investigated the effect of hydrogen annealing in the temperature ra nge from 850 to 1200 degrees C on oxygen precipitation and gate oxide integrity in Czochralski Si wafers. The bulk microdefect density of dy namic random access memory thermal simulation wafers showed a strong d ependence on the ramp-up rate conditions of hydrogen annealing. The ga te oxide integrity improved after hydrogen annealing at temperatures a bove 1000 degrees C. However, for better stability of the gate oxide i ntegrity after the heat treatment, higher temperature annealing is nec essary. We observed that the effect of hydrogen annealing was limited to the near surface, because the gate oxide integrity of hydrogen-anne aled wafers degraded to that for nonannealed wafers after repolishing.