DELETERIOUS EFFECTS OF AN OXIDIZING DRIVE-IN AMBIENT ON IMPLANTED ARSENIC EMITTERS IN (111) SILICON

In 〈111〉-oriented silicon, annealing high-dose (∼1×1016/cm2) implanted layers of arsenic in an ambient containing more than a few tenths of 1% oxygen in nitrogen results in dislocation networks that extend well beyond the implanted regions. As the oxygen concentration in the drive-in step is increased, the lateral extent and density of the dislocation loops increases. Electrically, the extended dislocation loops cause leaky emitter-base junctions and also emitter-to-collector leakage of the punch-through type. By controlling the drive-in ambient to 0.1% oxygen in nitrogen, we have prevented the formation of these extended dislocations for arsenic doses up to 2×10 16/cm2.