Indium antimonide (InSb) photodiode with ring contact and square bonding pod. InSb photodiodes were fabricated by AFRL and University of Dayton for mid-wave infrared detection. (AFRL Image) Photodiodes Doped by Ion Implantation Show Promise for Advanced Photodiode Fabrication by Beverly Thompson, AFRL/RYOX Sensors 11/23/2011 - WRIGHT-PATTERSON AIR FORCE BASE, Ohio -- Researchers at AFRL and the University of Dayton collaborated to fabricate indium antimonide (InSb) photodiodes for mid-wave infrared (MWIR) detection. These photodiodes were doped using ion implantation, which provides greater control over doping profiles than the commonly used thermal diffusion technique. This improved control could provide a method for producing advanced photodiode structures such as avalanche photodiodes (APD) for high performance detection in the MWIR. The researchers performed a detailed study on the implantation depths and thermal annealing affects on the doping profile. They determined that software modeling accurately predicted the doping profile for implant energies in the 20-160keV range, suggesting ion implantation is a viable technique for producing buried doping layers, a prerequisite for the fabrication of advanced diode structures. The development of this photodiode fabrication process is a stepping stone toward the development of MWIR imaging arrays. Imaging arrays fabricated in AFRL facilities will allow the integration of polarimetric and plasmonic structures into the fabrication process, for next-generation imaging array technology. These advanced structures will allow arrays to combine polarimetry, MWIR, and other imaging modalities for more versatile imagers in very small low-power form factors.