Impact of a Cooling Process on the Dopant Activity of Platinum in Silicon

摘要

In this work we show that the cooling rate following a platinum diffusion strongly influences the electrical conductivity in weakly phosphorus doped silicon. Diffusions were performed at the temperature of 910℃ for 16 hours. Spreading resistance profile analyses clearly show an retype to p-type conversion under the surface when samples are slowly cooled. A compensation of the phosphorus donors is only observed when samples are quenched. This mechanism is reversible. One Pt related deep level located at 0.427 eV is assumed to be at the origin of the type conversion mechanism. Its concentration increases during the cooling step when a low cooling rate is applied. This platinum related acceptor center is likely associated with fast interstitial Pt atoms or intrinsic point defects.