Processes for suppressing minority carrier lifetime degradation in silicon wafers

摘要

Processes for suppressing minority carrier lifetime degradation in silicon wafers are disclosed. The processes involve quench cooling the wafers to increase the density of nano-precipitates in the silicon wafers and the rate at which interstitial atoms are consumed by the nano-precipitates.

主权项

1. A process to suppress minority carrier lifetime degradation related to a minority carrier lifetime degradation defect in a silicon wafer comprising boron, boron being present in the wafer in a concentration of at least about 1013 atoms/cm3, the degradation defect comprising a fast-diffusing component and a dimeric oxygen-containing component, the process comprising:
heating the silicon wafer to a temperature T1, which is sufficient to dissolve pre-existing nano-precipitates of the fast-diffusing component of the degradation defect; cooling the silicon wafer from T1 to a temperature T2 at a cooling rate R1 of at least about 100° C./sec; and cooling the silicon wafer from T2 to a temperature T3 at a cooling rate R2, wherein the ratio of R1 to R2 is at least about 2:1.