Low-temperature formation of local Al contacts to a-Si:H-passivated Si wafers

We have passivated boron-doped, low-resistivity crystalline silicon wafers on both sides by a layer of intrinsic, amorphous silicon (a-Si:H). Local aluminum contacts were subsequently evaporated through a shadow mask. Annealing at 210degreesC in air dissolved the a-Si:H underneath the Al layer and reduces the contact resistivity from above 1 Omega cm(2) to 14.9 m Omega cm(2). The average surface recombination velocity is 124 cm/s for the annealed samples with 6% metallization fraction. In contrast to the metallized regions, no structural change is observed in the non-metallized regions of the annealed a-Si:H film, which has a recombination velocity of 48 cm/s before and after annealing. Copyright (C) 2004 John Wiley Sons, Ltd.