The x-ray imaging system comprises an x-ray source for producing an x-ray beam having an energy of at least 30 kVp and an x-ray detector. The x-ray detector comprises a solid state integrated circuit having a silicon substrate and a plurality of charge storage devices. The detector is responsive to x-rays of at least 30 keV to directly produce free electrons which interact with the charge storage devices.

X-ray imaging system and solid state detector therefor

A review of radiation-induced displacement damage effects in semiconductor devices is presented, with emphasis placed on silicon technology. The history of displacement damage studies is summarized, and damage production mechanisms are discussed. Properties of defect clusters and isolated defects are addressed. Displacement damage effects in materials and devices are considered, including effects produced in silicon particle detectors, visible imaging arrays, and solar cells. Additional topics examined include NIEL scaling, carrier concentration changes, random telegraph signals, radiation hardness assurance, and simulation methods for displacement damage. Areas needing further study are noted.

Displacement Damage Effects in Irradiated Semiconductor Devices

Two important classes of radiation damage to the scientific CCD are discussed, namely bulk and ionization effects. Bulk damage or displacement damage is a process in which silicon atoms are displaced from their normal lattice positions by high energy photons or particles. Single atomic displacements or cluster defect damage in silicon is produced depending on the energy and type of radiation experienced by the detector. Bulk damage creates trapping sites within the CCD's signal channel which in turn degrades CTE performance. Ionization-induced damage induces a buildup of charge in the CCD's gate insulator causing the sensor's drive operating windows to shift (i.e. flat-band shift). In addition, ionization damage creates unwanted electronic sites at the gate's interface causing the CCD's dark current to increase. >

Radiation damage in scientific charge-coupled devices

Photonic imagers are being increasingly used in space systems, where they are exposed to the space radiation environment. Unique properties of these devices require special considerations for radiation effects. This paper summarizes the evolution of radiation effects understanding in infrared detector technology, charge coupled devices, and active pixel sensors. The paper provides a discussion of key radiation effects developments and a view of the future of the technologies from a radiation effects perspective.

Radiation effects on photonic imagers-a historical perspective

This article presents a new technology for fabrication of a single-phase CCD. This new technology called virtual phase (VP) employs only a single level gate structure, and is, therefore, ideally suited for fabrication of large-area high-performance devices with high yield, The fundamentals of operation of VP CCD's are discussed, and the advantages and limitations of this new technology are presented. The design, fabrication, and operation of a 490 × 328 TV compatible VP imager is described, and performance parameters as well as imagery are presented.

Virtual phase technology: A new approach to fabrication of large-area CCD's

The permanent ionizing and neutron radiation-induced degradation in silicon charge-coupled devices, (CCD's), along with transient upset effects, are reviewed. The operation of a threshold voltage insensitive CCD input technique in a total dose radiation environment is evaluated. CCD structural design rules for decreasing ionizing radiation sensitivity are presented. The increased total ionizing dose tolerance of CCD's fabricated with a radiation hard oxide is described. Liquid nitrogen temperature irradiation effects in CCD's are discussed.

J. Killiany

Papers

Radiation Effects on Silicon Charge-Coupled Devices