Excimer Laser Dopant Activation of Backside Illuminated CCD's
Patent, Filed 14 Aug 95, patented 18 Nov 97
DEPARTMENT OF THE NAVY WASHINGTON DC
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A method uses an excimer laser to activate previously implanted dopant species in the backside of a backside-illuminated CCD or to incorporate dopant ions from a gaseous ambient into the backside of a backside-illuminated CCD and simultaneously activate. The controlled ion implantation of the backside and subsequent thin layer heating by the short wavelength pulsed excimer laser energy activates the dopant and provides for an improved dark current response and improved spectral response. The energy of the pulsed excimer laser is applied uniformly across a backside-illuminated CCD in a very thin layer of the semiconductor substrate usually silicon material that requires annealing to uniformly activate the dopant. The very thin layer of the material can be heated to exceedingly high temperatures on a nanosecond time scale white the bulk of the delicate CCD substrate remains at low temperature. Repair of semiconductor dies by effecting a uniform annealing enables salvage and utilization of otherwise discardable components by bringing their dark current response to within an acceptable range.
- Electrical and Electronic Equipment
- Lasers and Masers