Delta-Doped CCDs as Low-Energy-Particle Detectors

Charge-coupled devices (CCDs) of a type developed previously for imaging in ultraviolet light have been found to be useful as detectors of electrons and other charged particles with kinetic energies as low as about 100 eV. Heretofore, solid-state electronic devices have generally not been useful for detecting particles with kinetic energies below the keV range. The devices in question are back-side-illuminated silicon CCDs with p+ delta (δ) doping at their back-side interfaces between silicon and surface layers of silicon dioxide. Such a device at an earlier stage of development was described in "Growth of δ-Doped Layer on Silicon CCD" (NPO-18688) in the Laser Tech Briefs edition of NASA Tech Briefs, Vol. 19, No. 2 (February 1995), page 11.