Oxygen gettering on buried layers at post-implantation annealing of hydrogen implanted Czochralski silicon

We investigated oxygen gettering by buried defect layers at post-implantation annealing of hydrogen implanted Czochralski (Cz) grown silicon. Hydrogen ions were implanted into p-type Ct and for comparison into p-type float zone (Fz) silicon at energies of 180 keV and doses of 2.7.10(16) cm(-2). For comparison helium implantation (E = 300 keV, D = 10(16) cm(-2)) was carried out, too. Annealing was done at temperatures between 400 degrees C and 1200 degrees C in a forming gas ambient. Hydrogen and oxygen concentration profiles were measured by secondary ion mass spectroscopy (SIMS). Spreading resistance analysis was used to obtain the resitivity profiles of the annealed samples. It is shown that the buried defect layers act as effective getter canters for hydrogen and oxygen atoms at appropriate heat treatments. The very effective oxygen gettering in hydrogen implanted Cz silicon is attributed to a hydrogen enhanced diffusion of oxygen towards buried defect layers. The observed changes of the resistivity after post-implantation annealing can be explained by oxygen precipitation and hydrogen enhanced thermal donor (TD) formation processes.