Method of fabricating a single photon avalanche diode imaging sensor
First Claim
1. A method of fabricating an avalanche photodiode pixel, the method comprising:
- growing a second doped semiconductor layer on a first doped semiconductor layer having a first doping concentration, wherein the second doped semiconductor layer is grown with a second doping concentration, and wherein the second doped semiconductor layer is of an opposite majority charge carrier type as the first doped semiconductor layer;
forming a doped contact region having a third doping concentration in the second doped semiconductor layer, wherein the second doped semiconductor layer is disposed between the doped contact region and the first doped semiconductor layer, and wherein the doped contact region is of a same majority charge carrier type as the second doped semiconductor layer, and wherein the third doping concentration is greater than the second doping concentration; and
forming a guard ring region in the second doped semiconductor layer, wherein the guard ring region is of an opposite majority charge carrier type as the second doped semiconductor layer, and wherein the guard ring region extends entirely through the second doped semiconductor layer and surrounds the doped contact region.
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Abstract
A method of fabricating an avalanche photodiode pixel includes growing a second doped semiconductor layer on a first doped semiconductor layer having a first doping concentration. The second doped semiconductor layer is grown with a second doping concentration and is of an opposite majority charge carrier type as the first doped semiconductor layer. A doped contact region having a third doping concentration is formed in the second doped semiconductor layer between the doped contact region and the first doped semiconductor layer. The doped contact region is of a same majority charge carrier type as the second doped semiconductor layer. The third doping concentration is greater than the second doping concentration. A guard ring region is formed in the second doped semiconductor layer, is of an opposite majority charge carrier type as the second doped semiconductor layer, and extends through the second doped semiconductor layer surrounding the doped contact region.
83 Citations
23 Claims
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1. A method of fabricating an avalanche photodiode pixel, the method comprising:
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growing a second doped semiconductor layer on a first doped semiconductor layer having a first doping concentration, wherein the second doped semiconductor layer is grown with a second doping concentration, and wherein the second doped semiconductor layer is of an opposite majority charge carrier type as the first doped semiconductor layer; forming a doped contact region having a third doping concentration in the second doped semiconductor layer, wherein the second doped semiconductor layer is disposed between the doped contact region and the first doped semiconductor layer, and wherein the doped contact region is of a same majority charge carrier type as the second doped semiconductor layer, and wherein the third doping concentration is greater than the second doping concentration; and forming a guard ring region in the second doped semiconductor layer, wherein the guard ring region is of an opposite majority charge carrier type as the second doped semiconductor layer, and wherein the guard ring region extends entirely through the second doped semiconductor layer and surrounds the doped contact region. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10)
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11. A method of image sensor system fabrication, the method comprising:
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forming a first doped semiconductor layer on a substrate, wherein the first doped semiconductor layer is grown with a first doping concentration; forming a second doped semiconductor layer on the first doped semiconductor layer, wherein the second doped semiconductor layer is grown with a second doping concentration, and wherein the second doped semiconductor layer is of an opposite majority charge carrier type as the first doped semiconductor layer; forming a plurality of avalanche photodiode pixels, wherein the plurality of avalanche photodiode pixels include a doped contact region disposed in the second doped semiconductor layer, and wherein the doped contact region is of a same majority charge carrier type as the second doped semiconductor layer and has a greater doping concentration than the second doped semiconductor layer; forming a guard ring region which extends entirely through the second doped semiconductor layer, wherein the guard ring region is of an opposite majority charge carrier type as the second doped semiconductor layer, and wherein the guard ring region separates individual pixels in the plurality of avalanche photodiode pixels; and connecting a logic wafer to the second doped semiconductor layer, wherein the second doped semiconductor layer is disposed between the logic wafer and the first doped semiconductor layer. - View Dependent Claims (12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23)
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Specification