Structure and formation method of semiconductor device with photodetector
A semiconductor device structure and a formation method are provided. The method includes forming a p-type doped region and an n-type doped region in a semiconductor substrate. The method also includes partially removing the semiconductor substrate to form a recess exposing portions of the p-type doped region and the n-type doped region. The method further includes epitaxially growing a buffer layer along sidewalls and a bottom of the recess. In addition, the method includes epitaxially growing a photo-sensing structure over the buffer layer. The photo-sensing structure contains germanium and tin.
1 . A method for forming a semiconductor device structure, comprising:
forming a p-type doped region and an n-type doped region in a semiconductor substrate;
partially removing the semiconductor substrate to form a recess exposing portions of the p-type doped region and the n-type doped region;
forming a buffer layer along sidewalls and a bottom of the recess; and
epitaxially growing a photo-sensing structure over the buffer layer, wherein the photo-sensing structure contains germanium and tin, and the photo-sensing structure is closer to a bottom of the semiconductor substrate than the n-type doped region.
2 . The method for forming a semiconductor device structure as claimed in claim 1 , wherein the buffer layer and the photo-sensing structure are epitaxially grown in-situ in a process chamber.
3 . The method for forming a semiconductor device structure as claimed in claim 2 , further comprising:
forming a silicon germanium cap directly on the photo-sensing structure.
4 . The method for forming a semiconductor device structure as claimed in claim 3 , wherein the silicon germanium cap is epitaxially grown in-situ in the process chamber.
5 . The method for forming a semiconductor device structure as claimed in claim 4 , further comprising:
forming a nitrogen-containing stressor layer over the silicon germanium cap.
6 . The method for forming a semiconductor device structure as claimed in claim 1 , wherein the photo-sensing structure has an atomic concentration of tin within a range from about 1% to about 15%.
7 . The method for forming a semiconductor device structure as claimed in claim 1 , further comprising:
forming a silicon germanium buffer layer along the sidewalls and the bottom of the recess before the buffer layer is formed.
8 . The method for forming a semiconductor device structure as claimed in claim 1 , wherein the photo-sensing structure is formed to have an inner portion and an outer portion, the outer portion is closer to a bottom of the buffer layer than the inner portion, the inner portion has a first atomic concentration of tin, the outer portion has a second atomic concentration of tin, and the first atomic concentration of tin is higher than the second atomic concentration of tin.
9 . The method for forming a semiconductor device structure as claimed in claim 1 , wherein the buffer layer is substantially free of tin.
10 . A method for forming a semiconductor device structure, comprising:
forming a p-type doped structure and an n-type doped structure surrounded by a substrate;
partially removing the substrate to form a recess partially exposing the p-type doped structure and the n-type doped structure;
forming a buffer layer along sidewalls and a bottom of the recess, wherein the buffer layer extends across a top and a bottom of the p-type doped structure; and
epitaxially growing a photo-sensing structure over the buffer layer, wherein the photo-sensing structure is a germanium-based epitaxial structure that contains tin.
11 . The method for forming a semiconductor device structure as claimed in claim 10 , wherein the buffer layer and the photo-sensing structure are epitaxially grown in-situ in a process chamber.
12 . The method for forming a semiconductor device structure as claimed in claim 10 , further comprising:
forming a second p-type doped structure and a second n-type doped structure, wherein the second p-type doped structure is over the p-type doped structure, the second n-type doped structure is over the n-type doped structure, the second p-type doped structure has a higher dopant concentration than the p-type doped structure, and the second n-type doped structure has a higher dopant concentration than the n-type doped structure.
13 . The method for forming a semiconductor device structure as claimed in claim 12 , further comprising:
forming a first semiconductor-metal compound structure over the second p-type doped structure, wherein the first semiconductor-metal compound structure contains p-type dopants;
forming a second semiconductor-metal compound structure over the second n-type doped structure, wherein the second semiconductor-metal compound structure contains n-type dopants;
forming a first conductive feature over the first semiconductor-metal compound structure; and
forming a second conductive feature over the second semiconductor-metal compound structure.
14 . The method for forming a semiconductor device structure as claimed in claim 10 , further comprising:
epitaxially growing a silicon germanium cap on the photo-sensing epitaxial structure; and
epitaxially growing a silicon cap on the silicon germanium cap, wherein the silicon cap is separated from the photo-sensing epitaxial structure by the silicon germanium cap.
15 . A method for forming a semiconductor device structure, comprising:
forming a p-type doped structure and an n-type doped structure at least partially surrounded by a substrate;
partially removing the substrate to form a recess extending into the p-type doped structure and an n-type doped structure; and
forming a photo-sensing structure over a bottom of the recess, wherein a portion of the photo-sensing structure is between the p-type doped structure and the n-type doped structure, the photo-sensing structure extends across a top and a bottom of the p-type doped structure, and the photo-sensing structure contains germanium and tin.
16 . The method for forming a semiconductor device structure as claimed in claim 15 , further comprising:
forming a buffer layer at least partially surrounded by the substrate before the photo-sensing structure is formed, wherein the buffer layer extends along a bottom and sidewalls of the photo-sensing structure.
17 . The method for forming a semiconductor device structure as claimed in claim 15 , further comprising:
epitaxially growing a first cap on the photo-sensing structure; and
epitaxially growing a second cap on the first cap, wherein the second cap is separated from the photo-sensing structure by the first cap.
18 . The method for forming a semiconductor device structure as claimed in claim 17 , wherein the first cap has a higher atomic concentration of germanium than the second cap.
19 . The method for forming a semiconductor device structure as claimed in claim 15 , wherein the photo-sensing structure is formed closer to a bottom of the substrate than the p-type doped structure.
20 . The method for forming a semiconductor device structure as claimed in claim 15 , further comprising:
forming an isolation structure extending into the substrate; and
forming a mask element covering the isolation structure, wherein the photo-sensing structure protrudes upward beyond a top of the mask element.