Pulsed laser diffusion of thin hole-barrier contacts in high purity germanium for gamma radiation detectors

A new method for the formation of hole-barrier contacts in high purity germanium (HPGe) is described, which consists in the sputter deposition of a Sb film on HPGe, followed by Sb diffusion produced through laser annealing of the Ge surface in the melting regime. This process gives rise to a very thin (<= 100 nm) n-doped layer, as determined by SIMS measurement, while preserving the defect-free morphology of HPGe surface. A small prototype of gamma ray detector with a Sb laser-diffused contact was produced and characterized, showing low leakage currents and good spectroscopy data with different gamma ray sources.