PIN radiation detectors and other test-structures have been fabricated on a FZ, high resistivity (2 kΩ·cm), n-type silicon substrate by a process that features three different, alternative extrinsic-gettering techniques. Extremely-low leakage-current values have been measured regardless of the gettering technique adopted, this confirming the effectiveness of gettering procedures in limiting the detector leakage current. In particular, devices exploiting a phosphorus-doped polysilicon backside layer as gettering site have shown the best results in terms of leakage-current and generation-lifetime values. Results from the electrical and optical characterization of such devices are reported and discussed.