Photodetector and method for forming the same
AssigneeTaiwan Semiconductor Manufacturing Company, Ltd.
InventorChan-Hong Chern
Life of this patent
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Abstract
A photodetector is provided. The photodetector includes a cathode electrode in a semiconductor layer, a light absorption material at least partially embedded in the semiconductor layer, an anode electrode over the light absorption material, and a lower buffer layer electrically connecting between the cathode electrode and the light absorption material. The lower buffer layer includes first SiGe layers vertically stacked and spaced apart from each other, and atomic percentages of germanium in the first SiGe layers increase in order as a level of a first SiGe layer increases from bottom to top.
Claims20
A photodetector, comprising:
- a cathode electrode in a semiconductor layer;
- a light absorption material at least partially embedded in the semiconductor layer;
- an anode electrode over the light absorption material;
- and
- a lower buffer layer electrically connecting between the cathode electrode and the light absorption material, wherein the lower buffer layer includes first SiGe layers vertically stacked and spaced apart from each other, and atomic percentages of germanium in the first SiGe layers increase in order as a level of a first SiGe layer increases from bottom to top.
A photodetector, comprising:
- a first superlattice structure comprising multiple pairs of silicon layer/silicon germanium layer;
- an intrinsic germanium on the first superlattice;
- a second superlattice structure on the intrinsic germanium, the second superlattice structure comprising multiple pairs of silicon layer/silicon germanium layer;
- a first electrode region on the second superlattice structure;
- a semiconductor layer surrounding the first superlattice structure and the intrinsic germanium;
- and
- a second electrode region in the semiconductor layer and spaced apart from the intrinsic germanium.
A method for forming a photodetector, comprising:
- implanting a dopant into a semiconductor layer to form a bottom electrode region;
- recessing the semiconductor layer to form a cavity;
- sequentially forming a first Si layer, a first SiGe layer, a second Si layer and a second SiGe layer on the semiconductor layer in the cavity, wherein a first germanium concentration of the first SiGe layer is lower than a second germanium concentration of the second SiGe layer;
- forming an intrinsic germanium on the second SiGe layer in the cavity;
- and
- forming a top electrode region over the intrinsic germanium.
Dependencies are inferred from the claim text.