Claims
- 1. A sensor for converting radiant energy into electrical signals comprising:
- a crystalline substrate having a first and second surface including means for passing radiant energy into said substrate,
- said substrate including doping atoms for generating electronic charge in response to the absorption of radiant energy and including impurity atoms of a first type which diffuse readily throughout the substrate at times said substrate is above 900.degree. C.,
- a first electrode formed in said first surface,
- a second electrode formed in said second surface,
- means for coupling a first voltage across said first and second electrodes to attract electronic charge to said first electrode, and a layer having a damaged crystalline lattice structure formed in said substrate to getter impurity atoms of said first type from said substrate at times when said substrate is above 900.degree. C. to enhance the majority carrier lifetime of the substrate material.
- 2. The sensor of claim 1 wherein said layer is formed by diffusing a high conentration of impurity atoms of a second type in said crystalline substrate to alter and disrupt the crystalline lattice structure.
- 3. The sensor of claim 2 wherein said high concentration of impurity atoms of a second type is at least 10.sup.19 atoms cm.sup.-3.
- 4. The sensor of claim 2 wherein said layer is in the range from 0.7 to 1 micrometer thick.
- 5. The sensor of claim 2 wherein said crystalline substrate is silicon, said majority carriers are holes and said impurity atoms of a first type include gold.
- 6. The sensor of claim 2 wherein said crystalline substrate is silicon, said majority carriers are holes and said impurity atoms of a first type include silver.
- 7. The sensor of claim 2 wherein said layer is formed in part by raising its temperture to at least 900.degree. C.
- 8. The sensor of claim 2 wherein said crystalline substrate is germanium.
- 9. The sensor of claim 2 wherein said crystalline substrate is an alloy of germanium.
- 10. The sensor of claim 2 wherein said crystalline substrate is an alloy of silicon.
- 11. The sensor of claim 1 wherein said layer is formed in said first surface of said substrate.
GOVERNMENT CONTRACT
The government has rights in this invention pursuant to contract under DAAG-53-76-C-0170 awarded by the Defense Logistics Agency.
US Referenced Citations (3)