Ion-Implanted Germanium Far-Infrared Photodetectors

Abstract

ABSTRACTGermanium Blocked Impurity-Band (BIB) detectors, which have potential applications for space-born far infrared astrophysics observations, have been fabricated by means of boron ion implantation on high-purity Ge substrates. These devices are sensitive beyond the cutoff wavelength of Ge photoconductors doped with shallow acceptors. The extended cutoff wavelength increases with applied bias and can reach up to 200μm at very low dark currents of less than 100 electrons/sec. In order to enhance the photo-response, high-energy (3MeV) implantation has been used to form a thicker infrared-active layer. The influence of both ion-implant energies and post-implant anneals on the performance of detectors will be presented. Generation of excess donors in the boron implanted region has been observed. Their origin and effect of device performance will be discussed.