Effective gettering of oxygen by high dose, high energy boron buried layers

We examined the gettering of oxygen by high energy implanted boron in the 3×10 cm to 2×10¹⁵ cm^-2 dose range. Boron implants getter oxygen effectively by enhancing the nucleation rate of oxygen precipitates at the buried layer peak depth. This process occurs over a wide range of annealing conditions. Vacancies resulting from the implant also enhance the nucleation rate, this effect is slight and limited to low anneal temperatures. Oxygen is gettered only to precipitates, no peaks were observed in pre-denuded wafers. Buried layers are effective at reducing surface oxygen levels in undenuded Czochralski silicon. A 1.5 MeV, 1×10¹⁵ cm^-2 boron implant followed by a 1 hour furnace anneal reduces the oxygen level In undenuded silicon down to <2×10¹⁷ cm^-3. This level is typical of denuded silicon, suggesting that buried layers can be a low cost and reduced cycle time alternative to denuded bulk wafers