Apparatus Comprising an Avalanche Photodiode
AssigneePrinceton Lightwave, Inc.
InventorsMark Allen Itzler, Rafael Ben-Michael
Life of this patent
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Abstract
Avalanche photodiodes are provided, wherein the APDs provide both high optical coupling efficiency and low dark count rate. The APDs are formed such that their cap layer has an active region of sufficient width to enable high optical coupling efficiency but the APD still exhibits a low dark count rate. These cap layers have a device area with an active region and an edge region, wherein the size of the active region is substantially matched to the mode-field diameter of an optical beam, and wherein the size of the edge region is made small so as to reduce the number of defects included. These APD designs maintain a substantially uniform gain and breakdown voltage, as necessary for practical use.
Claims21
1-25. (canceled)
A photodiode comprising a semiconductor layer for providing avalanche multiplication of electrical carriers, wherein said semiconductor layer has a thickness, Tc, and wherein said semiconductor layer comprises:
- an active region;
- and
- an edge region having an edge-region width, wherein said edge-region width is in the range of substantially 0.5Tc to substantially 3Tc.
A photodiode comprising a semiconductor layer for providing avalanche multiplication of electrical carriers, wherein said semiconductor layer has a thickness, Tc, and wherein said semiconductor layer comprises:
- an active region that has an active-region width that is within the range of substantially 0.25Tc to substantially 2Tc, wherein said active-region is doped with a first dopant to a first junction depth, and wherein said first junction depth is within the range of approximately 0.5Tc to approximately 0.98Tc;
- and
- an edge region that has an edge-region width that is within the range of approximately 0.5Tc to approximately 3Tc, wherein said edge region and said active region are contiguous, and wherein said edge-region is doped with a second dopant to a second junction depth, and further wherein said second junction depth has an average junction depth that is less than said first junction depth;
- wherein said active region has a substantially uniform breakdown voltage, Vba, and wherein said edge region has a substantially uniform breakdown voltage, Vbe, and further wherein Vbe is greater than or equal to 0.9Vba.
Dependencies are inferred from the claim text.