(Invited) Microdefects in Czochralski-Grown Silicon Crystals and Their Application to Gettering Technique

Microdefects in Czochralski-grown (CZ) silicon crystals are induced by thermal treatments used in an LSI process. They are detrimental to device performance, if they are formed near the surface. The microdefects originate in the precipitation of oxygen involved in CZ crystals. However, it is possible to reduce the microdefect density after thermal treatments without decreasing the oxygen concentration by controlling crystal growth condition. On the other hand, the microdefects serve as gettering sites for both harmful impurities and surface defects, if their formations are confined to the interior of the wafer. This is called the intrinsic gettering (I-G) phenomenon. The I-G technique is successfully applied to a lifetime improvement, a heavy metal gettering, and an elimination of surface defects.