APPLICATION OF TECHNOLOGY:
- Medical Imaging
- Other Digital Scanning technologies
- Inexpensive and efficient
- High quantum efficiency without thinning
- Backlighting in the blue wavelenths; improved red wavelength performance
- Ease of fabrication
Stephen Holland at Berkeley Lab has developed an invention that comprises a combination of a low resistivity, or electrically conducting, silicon layer that is transparent to long or short wavelength photons and is attached to the backside of a photon-sensitive layer of silicon, such as a silicon wafer or chip. The window is applied to photon sensitive silicon devices such as photodiodes, charge-coupled devices, active pixel sensors, low-energy x-ray sensors and other radiation detectors. The silicon window is applied to the back side of a photosensitive silicon wafer or chip so that photons can illuminate the device from the backside without interference from the circuit printed on the frontside. A voltage sufficient to fully deplete the high-resistivity photosensitive silicon volume of charge carriers is applied between the low-resistivity back window and the front, patterned, side of the device. This allows photon-induced charge created at the backside to reach the front side of the device and to be processed by any circuitry attached to the front side. Using the inventive combination, the photon sensitive silicon layer does not need to be thinned beyond standard fabrication methods in order to achieve full charge-depletion in the silicon volume. In one embodiment, the inventive backside window is applied to high resistivity silicon to allow backside illumination while maintaining charge isolation in CCD pixels.
STATUS: U.S. Patent #6,025,585. Available for licensing in all fields of use, including use for positron emission tomography, as well as x-ray imaging of all kinds, with the exception of the field of photodiodes to perform single photon nuclear medicine procedures.
REFERENCE NUMBER: IB-1204
SEE THESE OTHER BERKELEY LAB TECHNOLOGIES IN THIS FIELD:
- High Quantum Efficiency Charge Coupled Device, IB-1204A
- High Efficiency Micro-Scale Light-Concentrating Arrays for Digital Imaging, IB-2279
FOR MORE INFORMATION PLEASE SEE: