Formation of buried p-type conducting layers in diamond

Deeply buried boron doped layers are realized in single crystal diamond using MeV ion implantation. Contact to the buried layers is accomplished using pulsed focused laser irradiation which is selectively absorbed in the implanted layer to form a graphite column up to the surface. The contacts are ohmic over a wide range of applied voltage. Implantation induced defects that are responsible for compensation of the accepters are identified. It is found that removal of these defects requires annealing temperatures of about 1450 degrees C, but once these defects are removed the buried B doped layer displays excellent-activation of the accepters with an activation energy of 0.372 eV. (C) 1997 American Institute of Physics.