Optical sensing apparatus
An optical sensing apparatus including: a substrate including a first material; an absorption region including a second material different from the first material; an amplification region formed in the substrate and configured to collect at least a portion of the photo-carriers from the absorption region and to amplify the portion of the photo-carriers; an interface-dopant region formed in the substrate between the absorption region and the amplification region; a buffer layer formed between the absorption region and the interface-dopant region; one or more field-control regions formed between the absorption region and the interface-dopant region and at least partially surrounding the buffer layer; and a buried-dopant region formed in the substrate and separated from the absorption region, where the buried-dopant region is configured to collect at least a portion of the amplified portion of the photo-carriers from the amplification region.
1 . An optical sensing apparatus comprising:
a substrate comprising a first material;
an absorption region comprising a second material different from the first material, the absorption region configured to receive an optical signal and generate photo-carriers in response to receiving the optical signal;
an amplification region formed in the substrate and configured to collect at least a portion of the photo-carriers from the absorption region and to amplify the portion of the photo-carriers;
an interface-dopant region formed in the substrate between the absorption region and the amplification region;
a buffer layer formed between the absorption region and the interface-dopant region; one or more field-control regions formed between the absorption region and the interface-dopant region and at least partially surrounding the buffer layer, wherein one or more properties of the one or more field-control regions are different from corresponding one or more properties of the buffer layer; and
a buried-dopant region formed in the substrate and separated from the absorption region, wherein the buried-dopant region is configured to collect at least a portion of the amplified portion of the photo-carriers from the amplification region.
2 . The optical sensing apparatus of claim 1 , wherein the one or more properties of the one or more field-control regions are different from the corresponding one or more properties of the buffer layer so as to form, under a reverse bias breakdown voltage, one or more punch-through regions and one or more blocking regions in the amplification region, wherein the one or more blocking regions are adjacent to the one or more field-control regions and the one or more punch-through regions are adjacent to the buffer layer.
3 . The optical sensing apparatus of claim 2 , wherein the one or more properties of the one or more field-control regions include a peak dopant concentration or a dopant depth.
4 . The optical sensing apparatus of claim 3 , wherein the one or more properties of the buffer layer include a peak dopant concentration or a dopant depth.
5 . The optical sensing apparatus of claim 4 , wherein a peak dopant concentration of the one or more field-control regions is higher than a peak dopant concentration of the buffer layer.
6 . The optical sensing apparatus of claim 4 , wherein a dopant depth of the one or more field-control regions is deeper than a dopant depth of the buffer layer.
7 . The optical sensing apparatus of claim 1 ,
wherein the absorption region includes a p-doped region,
wherein the interface-dopant region is p-doped,
wherein the one or more field-control regions are p-doped, and
wherein the buried-dopant region is n-doped.
8 . The optical sensing apparatus of claim 1 , wherein the interface-dopant region further comprises:
one or more first interface-dopant regions and one or more second interface-dopant regions at least partially surrounding the one or more first interface-dopant regions,
wherein a peak dopant concentration of the one or more first interface-dopant regions is lower than a peak dopant of the one or more second interface-dopant regions, or a dopant depth of the one or more first interface-dopant regions is deeper than a dopant depth of the one or more second interface-dopant regions.
9 . The optical sensing apparatus of claim 1 , wherein the buried-dopant region further comprises:
one or more first buried-dopant regions and one or more second buried-dopant regions at least partially surrounding the one or more first buried-dopant regions,
wherein a peak dopant concentration of the one or more first buried-dopant regions is higher than a peak dopant of the one or more second buried-dopant regions, or a dopant depth of the one or more first buried-dopant regions is deeper than a dopant depth of the one or more second buried-dopant regions.
10 . The optical sensing apparatus of claim 1 , further comprising one or more sidewall-dopant regions surrounding the absorption region.
11 . The optical sensing apparatus of claim 1 , wherein the absorption region has a gradient doping profile.
12 . The optical sensing apparatus of claim 1 , wherein the first material comprises silicon and the second material comprises germanium.
13 . The optical sensing apparatus of claim 1 , wherein the absorption region is at least partially embedded in the substrate.
14 . The optical sensing apparatus of claim 1 , wherein the absorption region is formed over a first surface of the substrate.
15 . The optical sensing apparatus of claim 14 , further comprising a lens structure formed over a second surface of the substrate, wherein the first surface is opposite to the second surface.
16 . The optical sensing apparatus of claim 15 , wherein the lens structure comprises a silicon microlens structure or a metalens structure.
17 . The optical sensing apparatus of claim 1 , wherein the buffer layer has a thickness not less than 50 nm.
18 . An optical sensing apparatus comprising:
a substrate comprising a first material;
an absorption region comprising a second material different from the first material, the absorption region configured to receive an optical signal and generate photo-carriers in response to receiving the optical signal;
an amplification region formed in the substrate configured to collect at least a portion of the photo-carriers from the absorption region and to amplify the portion of the photo-carriers;
multiple interface-dopant regions formed in the substrate between the absorption region and the amplification region, wherein a distance between two interface-dopant regions of the multiple interface-dopant regions is below a threshold value; and
a buried-dopant region formed in the substrate and separated from the absorption region, wherein the buried-dopant region is configured to collect at least a portion of the amplified portion of the photo-carriers from the amplification region,
wherein under a reverse bias breakdown voltage, multiple blocking regions are formed in the amplification region adjacent to the multiple interface dopant regions, and multiple punch-through regions are formed in the amplification region and in between any two adjacent blocking regions of the multiple blocking regions.
19 . The optical sensing apparatus of claim 18 , wherein the threshold value is 500 nm.