Co-implantation of Be+O and Mg+O into GaN

Beryllium and magnesium were co-implanted with oxygen into GaN at precise donor-to-acceptor ratios of 0.5–2. High activation efficiency was achieved for Be+O co-implants at a donor–acceptor ratio of 2 and anneal temperatures of 1050–1100 °C. The activation process was not a simple, single-step mechanism. Hall data indicated a relatively low (⩽100 meV) ionization energy for Be in the co-implanted samples. This process may have application in improving p-ohmic contact resistance by selective area Be+O implantation. By sharp contrast Mg+O co-implants produced n-type conductivity under all conditions.