Geiger mode avalanche photodiode
First Claim
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1. An avalanche photodiode comprising:
- a semiconductor depletion region;
an anode;
a cathode;
wherein incident photons having a wavelength in the blue end of the visible spectrum are absorbed in the depletion region so as to generate charge carriers, and wherein the charge carriers undergo impact ionization in the depletion region so as to generate an avalanche current in the photodiode.
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Abstract
A avalanche mode photodiode array (102) is fabricated using a silicon on insulator wafer and substrate transfer process. The array includes a plurality of photodiodes (100). The photodiodes (100) include an electrically insulative layer (206), a depletion region (204), and first (208) and second (210) doped regions. An interconnection layer (212) includes electrodes (214, 216) which provides electrical connections to the photodiodes. The photodiode array (102) is carried by a handle wafer (217).
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Citations
34 Claims
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1. An avalanche photodiode comprising:
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a semiconductor depletion region; an anode; a cathode; wherein incident photons having a wavelength in the blue end of the visible spectrum are absorbed in the depletion region so as to generate charge carriers, and wherein the charge carriers undergo impact ionization in the depletion region so as to generate an avalanche current in the photodiode. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10)
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11. A method of manufacturing an array of avalanche photodiodes using a silicon on insulator wafer, which wafer includes a substrate, a silicon layer, and a buried oxide layer disposed physically between the substrate and the silicon layer, the method comprising:
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forming a plurality of avalanche photodiodes in the silicon layer, the photodiodes including an anode, a cathode, and a depletion region; forming a plurality of electrodes in electrical communication with the anodes and cathodes of respective photodiodes, wherein the plurality of electrodes are disposed on a side of the silicon layer which is opposite the buried oxide layer; forming a plurality of isolation regions by etching a plurality of trenches which extend to the buried oxide layer which isolates each of the plurality of photodiodes from adjacent photodiodes; and removing the substrate, whereby the photodiodes are illuminated through the buried oxide layer. - View Dependent Claims (12, 13, 14, 15, 16, 17)
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18. A photodiode array produced using a silicon on insulator wafer, which wafer includes a substrate, a silicon layer, and a buried oxide layer disposed physically between the substrate and the silicon layer, wherein the photodiode array is produced using a process comprising:
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forming a plurality of avalanche photodiodes in the silicon layer, the photodiodes including an anode, a cathode, and a depletion region; forming a plurality of electrodes in electrical communication with the anodes and cathodes of respective photodiodes, wherein the plurality of electrodes are disposed on a side of the photodiodes opposite the buried oxide layer; attaching a handle wafer to the silicon on insulator wafer, wherein the electrodes are disposed physically between the handle wafer and the photodiodes; forming a plurality of isolation regions by etching a plurality of trenches which extend to the buried oxide layer which isolates each of the plurality of photodiodes from adjacent photodiodes; and removing the substrate from the silicon on insulator wafer, whereby the photodiodes are illuminated through the buried oxide layer. - View Dependent Claims (19)
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20. An avalanche photodiode comprising:
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a first doped semiconductor region which forms a cathode of the photodiode; a second doped semiconductor region which forms an anode of the photodiode; a third semiconductor region in optical communication with a light receiving face of the photodiode, wherein substantially all of the third semiconductor region is depleted when the photodiode is operated in the avalanche mode; an interconnection layer including a first electrode in electrical communication with the first doped semiconductor region and a second electrode in electrical communication with the second doped semiconductor region, wherein the third semiconductor region is disposed physically between the interconnection layer and the light receiving face. - View Dependent Claims (21, 22, 23, 24, 25, 26, 27, 28, 29, 30)
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31. An apparatus comprising:
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an examination region; an object support adapted to support an object under examination in the examination region; a radiation detector array including; a radiation sensitive face which faces the examination region; an array of avalanche photodiodes, wherein each photodiode includes an anode, a cathode, and a depletion region, wherein photons absorbed in the depletion region of a photodiode generate charge carriers, and wherein the charge carriers undergo impact ionization in the depletion region of the photodiode so as to generate an avalanche current in the photodiode; an interconnection layer including a plurality of electrodes which provide electrical connections to the photodiodes, wherein the interconnection layer is disposed on a side of the photodiode array which is opposite the radiation receiving face, and wherein the interconnection layer contains a quenching resistor. - View Dependent Claims (32, 33, 34)
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Specification