GaAsP Photo-cathode process improvement

Intevac has been manufacturing high performance III-V semiconductor photocathode-based electron bombarded sensors for low light level imaging and photon detection for over fifteen years. The focus has been long-range target identification at 1.5 microns, light detection and ranging at 1.06 microns, and VIS-NIR night vision systems. Intevac’s wide range of sensors and detector products have been optimized for these applications using high quantum efficiency (QE) gallium arsenide (GaAs) and indium gallium arsenide/indium phosphide (InGaAs/InP) photocathodes. Intevac has invested heavily in transitioning its core photocathode manufacturing processes from single-wafer, metal organic chemical vapor deposition (MOCVD) development tools to state-of-the-art, multi-wafer MOCVD production tools for high volume, low cost manufacturing. Several high priority Navy programs require the use of detectors and sensors with high performance in the blue-green portion of the electromagnetic spectrum. These devices have typically been manufactured using gallium arsenide phosphide (GaAsP) photocathodes in order to achieve optimum QE in the blue-green wave-band. Historically, Intevac’s MOCVD development tools have not been able to produce GaAsP photocathodes with stable QE and wafer yield. The purpose of this SBIR is to develop a process to consistently produce high yield, high QE GaAsP photocathodes using Intevac’s state-of-the-art MOCVD production tools.