Ion Implanted N-Type Contact for High-Purity Germanium Radiation Detectors

Thin large-area n+ contacts on high-purity germanium detectors have been produced by implantation of 25 keV phosphorous ions. The contacts show leakage current of < 10-9 A up to fields of > 2000 V/cm. Unannealed lattice damage may still limit the maximum applied field, but proper surface treatment prior to implantation and subsequent annealing steps have resulted in a dramatic improvement in the applied field. Spectra are presented which demonstrate that the n+ window is thin and the spectrometer performance is excellent.