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 210°C in air dissolved the a‐Si:H underneath the Al layer and reduces the contact resistivity from above 1 Ω cm2to 14·9 m Ω cm2. 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.