The development of an effective proximity gettering process is a key material engineering consideration for advanced semiconductor devices fabricated on 300-mm silicon wafers. Effective intrinsic gettering can be achieved by applying rapid thermal annealing (RTA) in a gas mixture of ammonia and argon at around 1150°C, which produces the desired "M"-shaped depth profile for the oxygen precipitates in the silicon bulk. The depth of the denuded zone is adjustable, and the peak density of the oxygen precipitates is above 1 × 1010 cm−3. The peak density strongly depends on the RTA temperature and the waferís initial interstitial oxygen concentration, so a higher temperature and higher initial interstitial oxygen concentration in the wafer lead to a higher density of oxygen precipitates. The "M"-shaped profile originates from the vacancy profile produced after cooling down from the RTA process. Utilizing the ammonia/argon gas mixture reduces the RTA temperature so as to obtain a higher density of oxygen precipitates and reduces slip in the wafer, as compared to performing RTA under a gas mixture of nitrogen and argon.

Keywords: RTA, oxygen precipitates, vacancy, proximity gettering, 300-mm silicon wafer