On the mechanism of carrier scattering at oxide precipitates in Czochralski silicon

摘要

Oxygen precipitation (OP) in Czochralski (CZ) silicon has been extensively and intensively studied in the past decades due to its significance for improving manufacturing yield of integrated circuits. Nevertheless, how OP affects the carrier transportation in CZ silicon has hardly been addressed. Here, we report that the carrier mobility is decreased to a certain extent while the carrier concentration is nearly unchanged due to significant OP in CZ silicon. Interestingly, such a decrease in mobility can be offset by copper (Cu) decoration of oxygen precipitates via Cu drive-in anneal at appropriate temperatures. It is clarified that the charges associated with the oxygen precipitate/silicon interface states exert additional scattering effect on the carrier transportation, leading to the decrease of carrier mobility as mentioned above. We believe that the present work gains an insight into OP in CZ silicon from the electrical point of view.