CN112331744B - Preparation method of photoelectric detector - Google Patents
Preparation method of photoelectric detector Download PDFInfo
- Publication number
- CN112331744B CN112331744B CN202110010821.3A CN202110010821A CN112331744B CN 112331744 B CN112331744 B CN 112331744B CN 202110010821 A CN202110010821 A CN 202110010821A CN 112331744 B CN112331744 B CN 112331744B
- Authority
- CN
- China
- Prior art keywords
- layer
- semiconductor material
- waveguide
- sub
- forming
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Active
Links
- 238000002360 preparation method Methods 0.000 title abstract description 8
- 230000003287 optical effect Effects 0.000 claims abstract description 140
- 239000000463 material Substances 0.000 claims abstract description 125
- 239000004065 semiconductor Substances 0.000 claims abstract description 113
- 238000000034 method Methods 0.000 claims abstract description 75
- 230000031700 light absorption Effects 0.000 claims abstract description 60
- 239000000758 substrate Substances 0.000 claims abstract description 55
- 230000008569 process Effects 0.000 claims abstract description 50
- 238000005530 etching Methods 0.000 claims abstract description 18
- XUIMIQQOPSSXEZ-UHFFFAOYSA-N Silicon Chemical compound [Si] XUIMIQQOPSSXEZ-UHFFFAOYSA-N 0.000 claims description 26
- 229910052710 silicon Inorganic materials 0.000 claims description 26
- 239000010703 silicon Substances 0.000 claims description 26
- 238000004519 manufacturing process Methods 0.000 claims description 19
- 230000007704 transition Effects 0.000 claims description 18
- 229910052732 germanium Inorganic materials 0.000 claims description 9
- GNPVGFCGXDBREM-UHFFFAOYSA-N germanium atom Chemical compound [Ge] GNPVGFCGXDBREM-UHFFFAOYSA-N 0.000 claims description 9
- 238000005253 cladding Methods 0.000 claims description 8
- 239000012212 insulator Substances 0.000 claims description 8
- 239000002131 composite material Substances 0.000 claims description 6
- 230000007423 decrease Effects 0.000 claims description 4
- 230000001276 controlling effect Effects 0.000 claims 1
- 230000001105 regulatory effect Effects 0.000 claims 1
- 239000002184 metal Substances 0.000 description 25
- VYPSYNLAJGMNEJ-UHFFFAOYSA-N Silicium dioxide Chemical group O=[Si]=O VYPSYNLAJGMNEJ-UHFFFAOYSA-N 0.000 description 18
- 239000000377 silicon dioxide Substances 0.000 description 9
- 235000012239 silicon dioxide Nutrition 0.000 description 9
- 125000006850 spacer group Chemical group 0.000 description 8
- 229910000577 Silicon-germanium Inorganic materials 0.000 description 7
- LEVVHYCKPQWKOP-UHFFFAOYSA-N [Si].[Ge] Chemical compound [Si].[Ge] LEVVHYCKPQWKOP-UHFFFAOYSA-N 0.000 description 6
- 238000000151 deposition Methods 0.000 description 6
- 239000002210 silicon-based material Substances 0.000 description 6
- 238000004088 simulation Methods 0.000 description 6
- 230000005540 biological transmission Effects 0.000 description 5
- 238000005516 engineering process Methods 0.000 description 5
- 230000001939 inductive effect Effects 0.000 description 5
- 238000001020 plasma etching Methods 0.000 description 5
- 230000008021 deposition Effects 0.000 description 4
- 238000001755 magnetron sputter deposition Methods 0.000 description 4
- 239000007769 metal material Substances 0.000 description 4
- 230000008878 coupling Effects 0.000 description 3
- 238000010168 coupling process Methods 0.000 description 3
- 238000005859 coupling reaction Methods 0.000 description 3
- 238000001514 detection method Methods 0.000 description 3
- 238000001259 photo etching Methods 0.000 description 3
- 230000009471 action Effects 0.000 description 2
- 238000005452 bending Methods 0.000 description 2
- 230000009286 beneficial effect Effects 0.000 description 2
- 230000008901 benefit Effects 0.000 description 2
- 239000000969 carrier Substances 0.000 description 2
- 230000008859 change Effects 0.000 description 2
- 238000004891 communication Methods 0.000 description 2
- 229910021419 crystalline silicon Inorganic materials 0.000 description 2
- 230000007547 defect Effects 0.000 description 2
- 230000000694 effects Effects 0.000 description 2
- 239000007772 electrode material Substances 0.000 description 2
- 230000006870 function Effects 0.000 description 2
- 230000006872 improvement Effects 0.000 description 2
- 238000000206 photolithography Methods 0.000 description 2
- 238000010521 absorption reaction Methods 0.000 description 1
- QVGXLLKOCUKJST-UHFFFAOYSA-N atomic oxygen Chemical compound [O] QVGXLLKOCUKJST-UHFFFAOYSA-N 0.000 description 1
- 230000015572 biosynthetic process Effects 0.000 description 1
- 230000000295 complement effect Effects 0.000 description 1
- 230000010485 coping Effects 0.000 description 1
- 238000010586 diagram Methods 0.000 description 1
- 238000009826 distribution Methods 0.000 description 1
- 230000010354 integration Effects 0.000 description 1
- 229910044991 metal oxide Inorganic materials 0.000 description 1
- 150000004706 metal oxides Chemical class 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 229910052760 oxygen Inorganic materials 0.000 description 1
- 239000001301 oxygen Substances 0.000 description 1
- 238000005498 polishing Methods 0.000 description 1
- 230000009467 reduction Effects 0.000 description 1
- 239000000126 substance Substances 0.000 description 1
- 238000009827 uniform distribution Methods 0.000 description 1
Images
Classifications
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
- H01L31/00—Semiconductor devices sensitive to infrared radiation, light, electromagnetic radiation of shorter wavelength or corpuscular radiation and specially adapted either for the conversion of the energy of such radiation into electrical energy or for the control of electrical energy by such radiation; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof
- H01L31/02—Details
- H01L31/0232—Optical elements or arrangements associated with the device
- H01L31/02327—Optical elements or arrangements associated with the device the optical elements being integrated or being directly associated to the device, e.g. back reflectors
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
- H01L31/00—Semiconductor devices sensitive to infrared radiation, light, electromagnetic radiation of shorter wavelength or corpuscular radiation and specially adapted either for the conversion of the energy of such radiation into electrical energy or for the control of electrical energy by such radiation; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof
- H01L31/08—Semiconductor devices sensitive to infrared radiation, light, electromagnetic radiation of shorter wavelength or corpuscular radiation and specially adapted either for the conversion of the energy of such radiation into electrical energy or for the control of electrical energy by such radiation; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof in which radiation controls flow of current through the device, e.g. photoresistors
- H01L31/10—Semiconductor devices sensitive to infrared radiation, light, electromagnetic radiation of shorter wavelength or corpuscular radiation and specially adapted either for the conversion of the energy of such radiation into electrical energy or for the control of electrical energy by such radiation; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof in which radiation controls flow of current through the device, e.g. photoresistors characterised by at least one potential-jump barrier or surface barrier, e.g. phototransistors
- H01L31/101—Devices sensitive to infrared, visible or ultraviolet radiation
- H01L31/102—Devices sensitive to infrared, visible or ultraviolet radiation characterised by only one potential barrier or surface barrier
- H01L31/109—Devices sensitive to infrared, visible or ultraviolet radiation characterised by only one potential barrier or surface barrier the potential barrier being of the PN heterojunction type
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
- H01L31/00—Semiconductor devices sensitive to infrared radiation, light, electromagnetic radiation of shorter wavelength or corpuscular radiation and specially adapted either for the conversion of the energy of such radiation into electrical energy or for the control of electrical energy by such radiation; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof
- H01L31/18—Processes or apparatus specially adapted for the manufacture or treatment of these devices or of parts thereof
- H01L31/1804—Processes or apparatus specially adapted for the manufacture or treatment of these devices or of parts thereof comprising only elements of Group IV of the Periodic System
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02P—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS
- Y02P70/00—Climate change mitigation technologies in the production process for final industrial or consumer products
- Y02P70/50—Manufacturing or production processes characterised by the final manufactured product
Abstract
The embodiment of the invention discloses a preparation method of a photoelectric detector, which comprises the following steps: providing a substrate comprising a first region of semiconductor material; performing an etching process on the first semiconductor material region to form an optical waveguide structure for transmitting an optical signal; the optical waveguide structure comprises a main waveguide part and a sub-waveguide part which are arranged at intervals along a first direction, the main waveguide part and the sub-waveguide part extend along a second direction, and the first direction is perpendicular to the second direction; forming a light absorption layer on the optical waveguide structure for detecting the optical signal transmitted in the optical waveguide structure.
Description
Technical Field
The application relates to the technical field of semiconductors, in particular to a preparation method of a photoelectric detector.
Background
The photoelectric detector is one of key photoelectric devices in optical communication, optical interconnection and photoelectric integration technologies, and has wide application in various fields of military and national economy at present, however, the existing photoelectric detector has the defects that the mode effective refractive index is difficult to regulate and control, the responsivity is low, and the like, and further improvement is needed.
Disclosure of Invention
In view of the above, embodiments of the present invention provide a method for manufacturing a photodetector to solve at least one problem in the related art.
In order to achieve the purpose, the technical scheme of the application is realized as follows:
the embodiment of the invention provides a preparation method of a photoelectric detector, which comprises the following steps:
providing a substrate comprising a first region of semiconductor material;
performing an etching process on the first semiconductor material region to form an optical waveguide structure for transmitting an optical signal; the optical waveguide structure comprises a main waveguide part and a sub-waveguide part which are arranged at intervals along a first direction, the main waveguide part and the sub-waveguide part extend along a second direction, and the first direction is perpendicular to the second direction;
forming a light absorption layer on the optical waveguide structure for detecting the optical signal transmitted in the optical waveguide structure.
In the above scheme, the substrate includes a silicon-on-insulator substrate, and the first semiconductor material region is a region on a top silicon layer of the silicon-on-insulator substrate;
the performing of the etching process on the first semiconductor material region specifically includes: and performing an etching process on the top silicon layer to form the optical waveguide structure.
In the above aspect, the secondary waveguide portion includes a first secondary waveguide portion and a second secondary waveguide portion, and the first secondary waveguide portion and the second secondary waveguide portion are distributed on both sides of the main waveguide portion along the first direction.
In the above-described aspect, at an end of the optical waveguide structure that receives the optical signal, an end surface area of the main waveguide portion is larger than an end surface area of the sub waveguide portion.
In the above aspect, each of the primary waveguide portion and the secondary waveguide portion has a curved waveguide structure, and a radius of the curved waveguide structure is greater than or equal to 10 μm.
In the above aspect, the cross-sectional area of the main waveguide portion decreases and the cross-sectional area of the sub waveguide portion increases in the second direction.
In the foregoing aspect, a distance between two sides of the optical waveguide structure along the first direction is greater than or equal to a dimension of the light absorption layer along the first direction.
In the foregoing aspect, after the forming the optical waveguide structure, the method further includes: forming a cladding layer covering the optical waveguide structure;
forming a transition layer on the covering layer, wherein the material of the transition layer is a composite material of a first semiconductor material and a second semiconductor material;
the forming of the light absorption layer specifically includes: and epitaxially growing a second semiconductor material on the transition layer to form the light absorption layer.
In the foregoing embodiment, the forming the light absorption layer specifically includes: forming the light absorbing layer by epitaxially growing a second semiconductor material;
after the forming the light absorbing layer, the method further comprises:
forming a first semiconductor material layer by epitaxially growing a first semiconductor material, the first semiconductor material layer covering at least two sidewalls of the light absorbing layer in the first direction;
performing a doping process to form a P-type doped region and an N-type doped region in the first semiconductor material layer; along the first direction, the light absorption layer is located between the P-type doped region and the N-type doped region.
In the foregoing embodiment, the forming the light absorption layer specifically includes: forming the light absorbing layer by epitaxially growing a second semiconductor material;
after the forming the light absorbing layer, the method further comprises:
forming a first semiconductor material layer by epitaxially growing a first semiconductor material, the first semiconductor material layer covering at least two sidewalls of the light absorbing layer in the first direction;
performing a doping process to form a P-type doped region, an intrinsic multiplication region and an N-type doped region in the first semiconductor material layer; along the first direction, the light absorption layer is located in the P-type doped region.
In the foregoing embodiment, the forming the light absorption layer specifically includes: forming the light absorbing layer by epitaxially growing a second semiconductor material;
after the forming the light absorbing layer, the method further comprises:
and forming a first semiconductor material layer by epitaxial growth, wherein the first semiconductor material layer covers two side walls of the light absorption layer along the first direction and the upper surface of the light absorption layer.
In the above scheme, the first semiconductor material is silicon; the second semiconductor material is germanium.
The embodiment of the invention provides a preparation method of a photoelectric detector, wherein the method comprises the following steps: providing a substrate comprising a first region of semiconductor material; performing an etching process on the first semiconductor material region to form an optical waveguide structure for transmitting an optical signal; the optical waveguide structure comprises a main waveguide part and a sub-waveguide part which are arranged at intervals along a first direction, the main waveguide part and the sub-waveguide part extend along a second direction, and the first direction is perpendicular to the second direction; forming a light absorption layer on the optical waveguide structure for detecting the optical signal transmitted in the optical waveguide structure. Thus, the photodetector formed by the preparation method provided by the embodiment of the present invention not only forms the main waveguide portion for receiving the optical signal, but also forms the sub-waveguide portion disposed at an interval with the main waveguide portion, and the sub-waveguide portion is utilized to limit the escape of the optical signal, so that the respective structural dimensions of the main waveguide portion and the sub-waveguide portion and the distance between the main waveguide portion and the sub-waveguide portion both affect the mode effective refractive index of the photodetector, and thus the adjustment and control means for increasing the mode effective refractive index of the photodetector based on the technical solution provided by the embodiment of the present application is beneficial to slowly coupling the optical signal from the optical waveguide structure to the light absorption layer, and improving the responsivity of the detector; moreover, by the preparation method provided by the embodiment of the invention, the optical field can be a basic mode when being transmitted in the optical waveguide structure, a high-order mode cannot be excited, and the uniform distribution of optical energy in the optical waveguide structure is ensured, so that the optical field distribution in the light absorption layer can be controlled.
Additional aspects and advantages of the invention will be set forth in part in the description which follows and, in part, will be obvious from the description, or may be learned by practice of the invention.
Drawings
Fig. 1 is a structural sectional view of a photodetector according to an embodiment of the present invention;
FIGS. 2a-2c are cross-sectional views of photodetectors that include optical waveguide structures provided in several different embodiments, respectively;
FIG. 3 is a graph illustrating simulation results of modal effective refractive indices of optical waveguide structures provided in several different embodiments;
FIG. 4 provides a cross-sectional view of a structure for other embodiments of a photodetector;
FIGS. 5a-5b are top views of different embodiments of optical waveguide structures in a photodetector;
fig. 6 is a schematic flow chart of a method for manufacturing a photodetector according to an embodiment of the present invention;
FIGS. 7a-7h are cross-sectional views of device structures in the fabrication process of a photodetector according to an embodiment of the present invention;
fig. 8a-8b are cross-sectional views of device structures in the fabrication process of a photodetector according to another embodiment of the present invention.
Description of reference numerals:
11-buried oxide layer; 12-top silicon layer (first semiconductor material region); 13-a cover layer; 131-a spacer layer;
20-an optical waveguide structure; 21-a main waveguide section; 22-a secondary waveguide section; 221-a first sub-waveguide section; 222-a second sub-waveguide section;
30. 30' -light absorbing layer (second semiconductor material layer); 31. 31' -a light absorbing doped region;
40. 40' -a first layer of semiconductor material; 41. a 41' -P + + doped region; 42. 42' -P type doped region; 43. 43' -N-type doped region; 44. 44' -N + + doped region; 45. 45' -a first portion; 46-intrinsic multiplication region;
a 50-transition layer;
61. 61' -a first metal electrode; 62. 62' -a second metal electrode;
70. 70' -filling layer.
Detailed Description
Exemplary embodiments disclosed in the present application will be described in more detail below with reference to the accompanying drawings. While exemplary embodiments of the present application are shown in the drawings, it should be understood that the present application may be embodied in various forms and should not be limited to the specific embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the disclosure to those skilled in the art.
In the following description, numerous specific details are set forth in order to provide a more thorough understanding of the present application. It will be apparent, however, to one skilled in the art, that the present application may be practiced without one or more of these specific details. In other instances, well-known features have not been described in order to avoid obscuring the present application; that is, not all features of an actual embodiment are described herein, and well-known functions and structures are not described in detail.
In the drawings, the size of layers, regions, elements, and relative sizes may be exaggerated for clarity. Like reference numerals refer to like elements throughout.
It will be understood that when an element or layer is referred to as being "on" … …, "adjacent to … …," "connected to" or "coupled to" other elements or layers, it can be directly on, adjacent to, connected to or coupled to the other elements or layers or intervening elements or layers may be present. In contrast, when an element is referred to as being "directly on … …," "directly adjacent to … …," "directly connected to" or "directly coupled to" other elements or layers, there are no intervening elements or layers present. It will be understood that, although the terms first, second, third, etc. may be used to describe various elements, components, regions, layers and/or sections, these elements, components, regions, layers and/or sections should not be limited by these terms. These terms are only used to distinguish one element, component, region, layer or section from another element, component, region, layer or section. Thus, a first element, component, region, layer or section discussed below could be termed a second element, component, region, layer or section without departing from the teachings of the present application. And the discussion of a second element, component, region, layer or section does not imply that a first element, component, region, layer or section is necessarily present in the application.
Spatial relationship terms such as "under … …", "under … …", "below", "under … …", "above … …", "above", and the like, may be used herein for ease of description to describe the relationship of one element or feature to another element or feature as illustrated in the figures. It will be understood that the spatially relative terms are intended to encompass different orientations of the device in use or operation in addition to the orientation depicted in the figures. For example, if the device in the figures is turned over, then elements or features described as "below" or "beneath" other elements or features would then be oriented "above" the other elements or features. Thus, the exemplary terms "below … …" and "below … …" can encompass both an orientation of up and down. The device may be otherwise oriented (rotated 90 degrees or at other orientations) and the spatial descriptors used herein interpreted accordingly.
The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the application. As used herein, the singular forms "a", "an" and "the" are intended to include the plural forms as well, unless the context clearly indicates otherwise. It will be further understood that the terms "comprises" and/or "comprising," when used in this specification, specify the presence of stated features, integers, steps, operations, elements, and/or components, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and/or groups thereof. As used herein, the term "and/or" includes any and all combinations of the associated listed items.
In order to thoroughly understand the present application, detailed steps and detailed structures will be presented in the following description in order to explain the technical solution of the present application. The following detailed description of the preferred embodiments of the present application, however, will suggest that the present application may have other embodiments in addition to these detailed descriptions.
Silicon photonics is a new generation technology based on silicon and silicon-based substrate materials (such as SiGe/Si, SOI, and the like) and utilizing a large-scale integrated circuit process (or called CMOS process) to develop and integrate optical devices, combines the characteristics of ultra-large-scale and ultra-high-precision manufacturing of the integrated circuit technology and the advantages of ultra-high speed and ultra-low power consumption of the photonic technology, and is a subversive technology for coping with the failure of the moore's law. This structure contributes to scalability in semiconductor wafer fabrication, thereby enabling cost reduction. The photoelectric detector is one of core devices of a silicon photon architecture and has the function of converting an optical signal into an electric signal. However, the direct detection efficiency of the crystalline silicon material in an optical communication waveband is very low due to the energy band structure of the crystalline silicon material, and although the III-V semiconductor material is more suitable for a photoelectric detector, the III-V semiconductor material is incompatible with a silicon process and cannot be effectively integrated with silicon in a single chip; in view of the compatibility of germanium materials with CMOS processes, the art proposes techniques for forming silicon germanium photodetectors using germanium materials as the light absorbing layer material.
The silicon photonic integrated chip can adopt a germanium-silicon material compatible with a CMOS (complementary metal oxide semiconductor) process to realize photoelectric detection, and the silicon material is used as an optical waveguide, and the germanium material absorbs photons.
The current photoelectric detector has the following defects: the process that the optical signal is coupled to the light absorption layer from the optical waveguide structure based on the evanescent wave is not easy to control, so that the mode effective refractive index of the optical waveguide structure is not easy to control, and meanwhile, the coupling efficiency is low, and the responsivity of the device is influenced.
Based on this, the following technical solutions of the embodiments of the present invention are proposed.
An embodiment of the present invention provides a photodetector, including: an optical waveguide structure for transmitting an optical signal, and a light absorption layer for detecting the optical signal transmitted in the optical waveguide structure; wherein the optical waveguide structure includes a main waveguide portion and a sub-waveguide portion, the optical waveguide structure receiving an optical signal through the main waveguide portion and restricting escape of the optical signal through the sub-waveguide portion; the main waveguide portion with vice waveguide portion sets up along first direction interval, light signal is in main waveguide portion with along the transmission of second direction in the vice waveguide portion, first direction with the second direction is perpendicular.
Please refer to fig. 1 in detail. As shown, the photodetector includes: an optical waveguide structure 20, and a light absorbing layer 30.
It should be understood that the photodetector may comprise a substrate. Here, the substrate may be an elemental semiconductor material substrate (e.g., a silicon (Si) substrate, a germanium (Ge) substrate, etc.), a composite semiconductor material substrate (e.g., a silicon germanium (SiGe) substrate, etc.), or a silicon-on-insulator (SOI) substrate, a germanium-on-insulator (GeOI) substrate, etc. In this embodiment, the substrate is taken as an SOI substrate for example, where the SOI substrate includes a bottom substrate (not shown in the figure), a buried oxide layer, and a top silicon layer; the bottom substrate can be a bottom silicon material; the buried oxide layer is positioned on the bottom layer substrate; the oxygen burying layer is a silicon dioxide layer for example; the top silicon layer is located on the buried oxide layer.
In some embodiments, the optical waveguide structure 20 is formed within the top silicon layer; the optical waveguide structure 20 is used for transmitting optical signals; the optical waveguide structure 20 includes a main waveguide portion 21 and a sub-waveguide portion 22, and the optical waveguide structure 20 receives an optical signal through the main waveguide portion 21 and restricts escape of the optical signal through the sub-waveguide portion 22; the main waveguide portion 21 and the sub-waveguide portion 22 are disposed at an interval along a first direction (please refer to an X direction in fig. 1), and the optical signal is transmitted along a second direction (please refer to a Y direction in fig. 1) in the main waveguide portion 21 and the sub-waveguide portion 22, where the first direction is perpendicular to the second direction. Here, the respective structural dimensions of the main waveguide portion and the sub-waveguide portion and the distance between the main waveguide portion and the sub-waveguide portion all affect the mode effective refractive index of the photodetector, so that the adjusting and controlling means for increasing the mode effective refractive index of the photodetector can be provided based on the technical solution provided by the embodiment of the present application, which is beneficial for slowly coupling the optical signal from the optical waveguide structure to the light absorption layer, and improves the responsivity of the detector.
It is to be understood that, in fig. 1, the X direction and the Y direction may be two directions parallel to the plane of the substrate, and the Z direction may be a direction perpendicular to the plane of the substrate; the X direction, the Y direction and the Z direction are vertical to each other.
In some embodiments, the first direction and the second direction may be two directions parallel to a plane of the substrate (e.g., with reference to X-direction and Y-direction in fig. 1, respectively). In other embodiments, the first direction may be any direction perpendicular to the second direction (e.g., any direction within the cross-section shown in fig. 1).
A silicon dioxide material is deposited on the buried oxide layer to form a capping layer 13. The cladding layer 13 covers the optical waveguide structure 20, i.e., the upper surface of the cladding layer 13 is higher than the upper surface of the optical waveguide structure 20.
The photodetector further includes: a light absorbing layer 30 for detecting the optical signal transmitted in the optical waveguide structure 20; the optical waveguide structures 20 and the light absorbing layers 30 are spaced apart in a third direction (see the Z direction in fig. 1), which is perpendicular to the second direction. In a specific embodiment, the first direction, the second direction and the third direction are perpendicular to each other. Here, the third direction may be a direction perpendicular to the plane of the substrate.
In order to detect the optical signal transmitted in the optical waveguide structure, the light absorbing layer is disposed opposite to the optical waveguide structure, and the light absorbing layer is located at an evanescent field position of the optical waveguide structure. In one embodiment, the main waveguide is disposed opposite to the light absorption layer. The superposition area of the projection of the main waveguide part and the light absorption layer along the third direction is larger than that of the projection of the sub waveguide part and the light absorption layer along the third direction; here, an overlapping area of the projection of the sub-waveguide and the light absorbing layer in the third direction may be greater than zero or equal to zero, that is, the projection of the sub-waveguide and the light absorbing layer in the third direction may or may not overlap.
In a specific embodiment, the secondary waveguide part 22 may include a first secondary waveguide part 221 and a second secondary waveguide part 222, and the first secondary waveguide part 221 and the second secondary waveguide part 222 are distributed on both sides of the primary waveguide part 21 along the first direction.
Here, the sub waveguide portion includes a first sub waveguide portion and a second sub waveguide portion, and an overlapping area of the first sub waveguide portion with the projection of the light absorbing layer in the third direction and an overlapping area of the second sub waveguide portion with the projection of the light absorbing layer in the third direction are both smaller than an overlapping area of the main waveguide portion with the projection of the light absorbing layer in the third direction.
Here, as shown in fig. 1, a distance between the main waveguide part 21 and the first sub-waveguide part 221 and a distance between the main waveguide part 21 and the second sub-waveguide part 222 may be equal, or, as shown in fig. 2a, a distance between the main waveguide part 21 and the first sub-waveguide part 221 and a distance between the main waveguide part 21 and the second sub-waveguide part 222 may not be equal.
Here, the number of the sub-waveguide portions 22 is two, that is, the first sub-waveguide portion 221 and the second sub-waveguide portion 222; in other embodiments, the number of the sub-waveguide portions 22 may be one, and in the embodiment shown in fig. 2b, the number of the sub-waveguide portions 22 is one, that is, the sub-waveguide portion 22 includes a first sub-waveguide portion 221 (only the first sub-waveguide portion 221 is described as an example); the first sub waveguide portions 221 are distributed on either side of the main waveguide portion 21 in the first direction.
In one embodiment, at one end of the optical waveguide structure 20 receiving the optical signal, the area of the end surface of the main waveguide portion 21 is larger than that of the end surface of the sub waveguide portion 22. Specifically, the secondary waveguide portion includes a first secondary waveguide portion and a second secondary waveguide portion, and an end surface area of the first secondary waveguide portion and an end surface area of the second secondary waveguide portion are both smaller than an end surface area of the main waveguide portion.
Here, when the number of the sub waveguide sections 22 is plural, the end surface areas of the sub waveguide sections 22 may be equal or may not be equal. In the embodiment shown in fig. 1, the end surface area of the first sub-waveguide portion 221 is equal to the end surface area of the second sub-waveguide portion 222; in the embodiment shown in fig. 2c, the area of the end face of the first sub-waveguide portion 221 is smaller than the area of the end face of the second sub-waveguide portion 222. In an embodiment where the heights of the sub-waveguides 22 are equal (e.g., all formed by etching the top silicon layer of the SOI substrate), the end surfaces of the sub-waveguides 22 are equal in area, specifically, the widths of the sub-waveguides 22 are equal; the area of the end surface of each of the sub waveguide portions 22 is not equal, specifically, the width of each of the sub waveguide portions 22 is not equal.
Fig. 3 is a diagram illustrating simulation results of mode effective refractive indices of optical waveguide structures provided in several different embodiments. As shown in fig. 3, different end surface areas of the main optical waveguide portion and the auxiliary optical waveguide portion generate different mode effective refractive indexes, so that the mode effective refractive index of the optical waveguide structure can be adjusted by adjusting the end surface areas of the main optical waveguide portion and the auxiliary optical waveguide portion. As shown in a, the width of the main waveguide is 400nm, the widths of the first and second sub-waveguides are both 100nm, the distance between the first sub-waveguide and the main waveguide and the distance between the second sub-waveguide and the main waveguide are both 100nm, and simulation results show that the mode effective refractive index of the photodetector with such an optical waveguide structure is 2.2612. As shown in b, the width of the main waveguide is 400nm, the widths of the first and second sub-waveguides are both 300nm, the distance between the first sub-waveguide and the main waveguide and the distance between the second sub-waveguide and the main waveguide are both 100nm, and the mode effective refractive index of the photodetector with such an optical waveguide structure is 2.2886 through simulation. As shown in c, the width of the main waveguide is 550nm, the widths of the first sub-waveguide and the second sub-waveguide are both 300nm, the distance between the first sub-waveguide and the main waveguide and the distance between the second sub-waveguide and the main waveguide are both 100nm, and the mode effective refractive index of the photodetector with such an optical waveguide structure is 2.5242 through simulation. As shown in d in the figure, the width of the main waveguide is 550nm, the widths of the first sub-waveguide and the second sub-waveguide are both 500nm, the distance between the first sub-waveguide and the main waveguide and the distance between the second sub-waveguide and the main waveguide are both 100nm, and the mode effective refractive index of the photodetector with such an optical waveguide structure is 2.5482 through simulation.
In one embodiment, a distance between both sides of the optical waveguide structure 20 in the first direction is greater than or equal to a dimension of the light absorbing layer 30 in the first direction.
The photodetector further includes: a spacer layer 131 and a transition layer 50 between the optical waveguide structure 20 and the light absorbing layer 30; wherein the spacer layer 131 is located on the optical waveguide structure 20; the transition layer 50 is located on the spacer layer 131, and the material of the transition layer 50 is a composite material of a first semiconductor material and a second semiconductor material; the light absorbing layer 30 is a second semiconductor material layer epitaxially grown on the transition layer 50. Here, by forming the transition layer 50, the growth quality of the light absorbing layer to be formed later can be effectively improved.
The spacer layer 131 is a portion of the cladding layer 13 above the optical waveguide structure 20; the spacer layer is made of silicon dioxide, and can prevent photogenerated carriers generated in the light absorption layer from diffusing to the optical waveguide structure.
In some embodiments, as shown in fig. 1, the photodetector further includes an epitaxially grown first semiconductor material layer 40, a P-type doped region 42 and an N-type doped region 43 being formed within the first semiconductor material layer 40; along the first direction, the light absorption layer 30 is located between the P-type doped region 42 and the N-type doped region 43 of the first semiconductor material layer 40.
Here, the P-type doped region 42 may be a P + doped region; the N-type doped region 43 may be an N + doped region.
In a specific embodiment, a P + + doped region 41 and an N + + doped region 44 may also be formed in the first semiconductor material layer 40. The light absorption layer 30 is located between the P-type doped region and the N-type doped region of the first semiconductor material layer 40, and specifically includes: the light absorbing layer 30 is located between the P + doped region and the N + doped region.
The light absorbing layer 30 further includes a light absorbing doped region 31 within the P-type doped region 42 and the N-type doped region 43. The part of the light absorption doped region 31 located in the P-type doped region 42 is doped P-type; the portion of the light absorbing doped region 31 located within the N-type doped region 43 is N-doped. It should be understood that the light absorbing layer 30 includes an intrinsic region, which is a core region for detecting an optical signal transmitted in the optical waveguide structure, in addition to the light absorbing doped region 31.
In the embodiment shown in FIG. 1, the dimension of the light absorption layer 30 along the X direction is 600nm to 1200nm, and the dimension along the Z direction is 300nm to 600 nm. In an embodiment where the first direction is the same as the X direction and the third direction is the same as the Z direction, the dimension of the light absorbing layer 30 along the first direction is 600nm to 1200nm, and the dimension along the third direction is 300nm to 600 nm.
In other embodiments, as shown in fig. 4, the photodetector further includes an epitaxially grown first semiconductor material layer 40 'having a P-type doped region 42', an intrinsic multiplication region 46, and an N-type doped region 43 'formed within the first semiconductor material layer 40'; along the first direction, the light absorption layer 30 'is located in the P-type doped region of the first semiconductor material layer 40'.
Here, the P-type doped region 42' may be a P + doped region; the N-type doped region 43' may be an N + doped region.
In a specific embodiment, a P + + doped region 41 ' and an N + + doped region 44 ' may also be formed in the first semiconductor material layer 40 '. The light absorption layer 30 'is located in the P-type doped region of the first semiconductor material layer 40', and specifically includes: the light absorbing layer 30' is located within the P + doped region.
The light absorbing layer 30 ' also includes light absorbing doped regions 31 ' within the P-type doped regions 42 '. The portion of the light-absorbing doped region 31 'located in the P-type doped region 42' is P-type doped.
It will be appreciated that the photodetector may be an avalanche photodetector. By arranging the intrinsic multiplication region, the avalanche multiplication effect can be further enhanced, and the detection effect is improved.
In the embodiment shown in FIG. 4, the dimension of the light absorption layer 30' along the X direction is 600nm to 1000nm, and the dimension along the Z direction is 200nm to 400 nm. In an embodiment where the first direction is the same as the X direction and the third direction is the same as the Z direction, the dimension of the light absorbing layer 30' in the first direction is 600nm to 1000nm, and the dimension in the third direction is 200nm to 400 nm.
In one embodiment, a first metal electrode 61 is disposed on the P + + doped region 41; a second metal electrode 62 is disposed on the N + + doped region 44.
A filling layer 70 is formed on the first semiconductor material layer 40; the first metal electrode 61 and the second metal electrode 62 include portions located within the filling layer 70, and upper surfaces of the first metal electrode 61 and the second metal electrode 62 are higher than an upper surface of the filling layer 70.
With continued reference to fig. 1, the first semiconductor material layer 40 further includes a portion (see 45 in fig. 1, hereinafter referred to as "first portion" 45) overlying the light absorbing layer 30. In other words, the upper surface of the light absorption layer 30 is lower than the upper surface of the first semiconductor material layer 40, and specifically includes: the top end of the light absorbing layer 30 is embedded in the first semiconductor material layer 40.
Here, the first portion 45 is an intrinsic layer.
On one hand, the first part can play a role in protecting the light absorption layer, so that the reliability of the device is improved; on the other hand, the first part can be used as an auxiliary mask in the doping process, so that the point aligning error and the angle error are reduced, the accuracy of the size of a doped region is improved, and the light absorption layer is protected from being doped to a certain extent.
In an embodiment of the present invention, the first semiconductor material is silicon; the second semiconductor material is germanium. As such, the photodetector is, for example, a silicon germanium photodetector; the light absorption layer is a germanium absorption layer; the optical waveguide structure can be a silicon waveguide; the transition layer is made of germanium-silicon.
In some embodiments, as shown in fig. 5a, the primary waveguide portion 21 and the secondary waveguide portion 22 each have a curved waveguide structure having a radius greater than or equal to 10 μm. The main waveguide 21 and the sub waveguide 22 have the same tendency of bending change. The main waveguide part and the auxiliary waveguide part are designed into a bent waveguide structure, so that the action lengths of the optical waveguide structure and the light absorption layer can be enhanced, and the responsivity and the bandwidth of the device are improved. In practical application, the curved waveguide structure may be a wavy line-shaped structure; the extending direction of the curved waveguide structure is consistent with the length direction of the light absorption layer.
In other embodiments, as shown in fig. 5b, the cross-sectional area of the main waveguide 21 decreases and the cross-sectional area of the sub-waveguide 22 increases along the second direction, i.e. along the transmission direction of the optical signal.
Further, the interval between the main waveguide portion and the sub-waveguide portion may be constant; in order to meet the requirements of adjusting the effective refractive index of different modes, the distance between the two can also be changed along the transmission direction of the optical signal.
The embodiment of the present invention further provides a method for manufacturing a photodetector, referring to fig. 6 specifically, as shown in the drawing, the method includes the following steps:
The following describes the method for manufacturing the photodetector of the present invention in further detail with reference to specific examples.
Fig. 7a to 7h are schematic cross-sectional views of device structures of a photodetector provided in an embodiment of the present invention during a manufacturing process.
First, referring to fig. 7a, a step 601 is performed to provide a substrate comprising a first semiconductor material region. The substrate may be an elemental semiconductor material substrate (e.g., a silicon (Si) substrate, a germanium (Ge) substrate, etc.), a composite semiconductor material substrate (e.g., a silicon germanium (SiGe) substrate, etc.), or a silicon-on-insulator (SOI) substrate, a germanium-on-insulator (GeOI) substrate, etc.
In the embodiment of the present invention, the substrate is an SOI substrate as an example, and the first semiconductor material region is a region where the top silicon layer 12 of the SOI substrate is located. The SOI substrate further comprises a buried oxide layer 11 underlying the top silicon layer 12 and a bottom substrate (not shown); the bottom substrate is a bottom silicon material; the buried oxide layer 11 is positioned on the bottom substrate; the buried oxide layer 11 is, for example, a silicon dioxide layer.
Next, referring to fig. 7b, step 602 is executed to perform an etching process on the first semiconductor material region 12 to form an optical waveguide structure 20 for transmitting an optical signal; the optical waveguide structure includes a main waveguide portion 21 and a sub-waveguide portion 22 spaced apart from each other along a first direction (see X direction in fig. 1), where the main waveguide portion 21 and the sub-waveguide portion 22 extend along a second direction (see Y direction in fig. 1), and the first direction is perpendicular to the second direction.
It should be noted that, in this embodiment, the first direction and the second direction are two directions parallel to the plane of the substrate (specifically, refer to the X direction and the Y direction in fig. 1, respectively).
The performing an etching process on the first semiconductor material region 12 specifically includes: an etching process is performed on the top silicon layer 12 to form the optical waveguide structure 20.
The etching process comprises photoetching, inductive plasma etching and other processes.
In an embodiment, the secondary waveguide portion 22 includes a first secondary waveguide portion 221 and a second secondary waveguide portion 222, and the first secondary waveguide portion 221 and the second secondary waveguide portion 222 are distributed on two sides of the primary waveguide portion 21 along the first direction.
Here, as shown in fig. 1, a distance between the main waveguide part 21 and the first sub-waveguide part 221 and a distance between the main waveguide part 21 and the second sub-waveguide part 222 may be equal, or, as shown in fig. 2a, a distance between the main waveguide part 21 and the first sub-waveguide part 221 and a distance between the main waveguide part 21 and the second sub-waveguide part 222 may not be equal.
Here, the number of the sub-waveguide portions 22 is two, that is, the first sub-waveguide portion 221 and the second sub-waveguide portion 222; in other embodiments, the number of the secondary waveguide 22 may be one. In the embodiment shown in fig. 2b, the number of the sub-waveguide portions 22 is one, that is, the sub-waveguide portion 22 includes a first sub-waveguide portion 221 (only the first sub-waveguide portion 221 is described as an example); the first sub waveguide portions 221 are distributed on either side of the main waveguide portion 21 in the first direction.
In one embodiment, at one end of the optical waveguide structure 20 receiving the optical signal, the area of the end surface of the main waveguide portion 21 is larger than that of the end surface of the sub waveguide portion 22.
Here, when the number of the sub waveguide sections 22 is plural, the end surface areas of the sub waveguide sections 22 may be equal or may not be equal. In the embodiment shown in fig. 1, the end surface area of the first sub-waveguide portion 221 is equal to the end surface area of the second sub-waveguide portion 222; in the embodiment shown in fig. 2c, the area of the end face of the first sub-waveguide portion 221 is smaller than the area of the end face of the second sub-waveguide portion 222. Since in the present embodiment, the optical waveguide structure 20 is formed by performing an etching process on the first semiconductor material region 12 (for example, by etching on the top silicon layer of the SOI substrate), the heights of the respective sub-waveguide portions 22 are formed to be equal, and thus the end surface areas of the respective sub-waveguide portions 22 are equal, specifically, the widths of the respective sub-waveguide portions 22 are equal; the area of the end surface of each of the sub waveguide portions 22 is not equal, specifically, the width of each of the sub waveguide portions 22 is not equal.
In some embodiments, as shown in fig. 5a, the primary waveguide portion 21 and the secondary waveguide portion 22 each have a curved waveguide structure having a radius greater than or equal to 10 μm. The main waveguide 21 and the sub waveguide 22 have the same tendency of bending change. The main waveguide part and the auxiliary waveguide part are designed into a bent waveguide structure, so that the action lengths of the optical waveguide structure and the light absorption layer can be enhanced, and the responsivity and the bandwidth of the device are improved. In practical application, the curved waveguide structure may be a wavy line-shaped structure; the extending direction of the curved waveguide structure is consistent with the length direction of the light absorption layer.
In other embodiments, as shown in fig. 5b, the cross-sectional area of the main waveguide 21 decreases and the cross-sectional area of the sub-waveguide 22 increases along the second direction, i.e. along the transmission direction of the optical signal.
Further, the interval between the main waveguide portion and the sub-waveguide portion may be constant; in order to meet the requirements of adjusting the effective refractive index of different modes, the distance between the two can also be changed along the transmission direction of the optical signal.
Next, fig. 7c and 7d are referenced.
Referring initially to fig. 7c, after forming the optical waveguide structure 20, the method further includes: forming a cladding layer 13 covering the optical waveguide structure 20; specifically, a silicon dioxide material may be deposited on the buried oxide layer 11, forming a capping layer 13; the cladding layer 13 covers the optical waveguide structure 20, i.e., the upper surface of the cladding layer 13 is higher than the upper surface of the optical waveguide structure 20.
In an actual process, after the formation of the covering layer 13, a step of planarizing the upper surface of the covering layer 13 may be further included, and specifically, a Chemical Mechanical Polishing (CMP) process may be used to make the covering layer 13 have a substantially flat upper surface.
The part of the covering layer 13 above the optical waveguide structure 20 is a spacing layer 131; the spacer layer may prevent photogenerated carriers generated within the light absorbing layer from diffusing into the light waveguide structure.
Referring next to fig. 7d, an epitaxial growth process is performed to form a transition layer 50 on the capping layer 13, wherein the material of the transition layer 50 is a composite material of the first semiconductor material and the second semiconductor material.
Specifically, the transition layer 50 is located above the spacer layer 131, i.e., the transition layer 50 is located above the optical waveguide structure 20.
Here, by forming the transition layer 50, the growth quality of the light absorbing layer to be formed later can be effectively improved.
The epitaxial growth process may specifically be a selective epitaxial growth process.
Next, referring to fig. 7e, step 603 is performed to form a light absorption layer 30 on the optical waveguide structure 20 for detecting the optical signal transmitted in the optical waveguide structure 20.
The forming of the light absorption layer 30 specifically includes: a second semiconductor material is epitaxially grown on the transition layer 50 to form the light absorbing layer 30.
Specifically, the light absorbing layer 30 is located above the optical waveguide structure 20, i.e., the optical waveguide structure is disposed opposite to the light absorbing layer; more specifically, the light absorbing layer 30 is located directly above the main waveguide 21. The overlapping area of the projection of the main waveguide 21 and the light absorbing layer 30 in the third direction is larger than the overlapping area of the projection of the sub waveguide 22 and the light absorbing layer 30 in the third direction; here, the overlapping area of the projection of the sub-waveguide 22 and the light absorbing layer 30 in the third direction may be greater than zero or equal to zero, that is, the projection of the sub-waveguide 22 and the light absorbing layer 30 in the third direction may or may not overlap.
The sub waveguide portion 22 includes a first sub waveguide portion 221 and a second sub waveguide portion 222, and an overlapping area of the first sub waveguide portion 221 and a projection of the light absorbing layer 30 in the third direction and an overlapping area of the second sub waveguide portion 222 and a projection of the light absorbing layer 30 in the third direction are both smaller than an overlapping area of the main waveguide portion 21 and a projection of the light absorbing layer 30 in the third direction.
Here, the process of epitaxially growing the second semiconductor material may be specifically a selective epitaxial growth process.
In one embodiment, a distance between both sides of the optical waveguide structure 20 in the first direction is greater than or equal to a dimension of the light absorbing layer 30 in the first direction.
Next, in some embodiments, after forming the light absorbing layer 30, the method further comprises: a first semiconductor material layer 40 is formed by epitaxially growing a first semiconductor material, and the first semiconductor material layer 40 covers at least two sidewalls of the light absorbing layer 30 in the first direction.
In other embodiments, referring to fig. 7f, after forming the light absorbing layer 30, the method further comprises: a first semiconductor material layer 40 is formed by epitaxially growing a first semiconductor material, and the first semiconductor material layer 40 covers both sidewalls of the light absorbing layer 30 in the first direction and an upper surface of the light absorbing layer 30.
The process of epitaxially growing the first semiconductor material may specifically be a selective epitaxial growth process.
In an actual process, after the first semiconductor material layer 40 is formed, a step of planarizing the upper surface of the first semiconductor material layer 40 may further be included, and specifically, a CMP process may be used to make the first semiconductor material layer 40 have a substantially flat upper surface.
Next, referring to fig. 7g, a doping process is performed to form a P-type doped region 42 and an N-type doped region 43 in the first semiconductor material layer 40; along the first direction, the light absorption layer 30 is located between the P-type doped region 42 and the N-type doped region 43.
Here, the P-type doped region 42 may be a P + doped region; the N-type doped region 43 may be an N + doped region.
In a specific embodiment, a P + + doped region 41 and an N + + doped region 44 may also be formed in the first semiconductor material layer 40. The light absorption layer 30 is located between the P-type doped region 42 and the N-type doped region 43, and specifically includes: the light absorbing layer 30 is located between the P + doped region and the N + doped region.
The first semiconductor material layer 40 further includes a portion (see 45 in fig. 7g, hereinafter referred to as "first portion" 45) covering the light absorption layer 30. In other words, the upper surface of the light absorption layer 30 is lower than the upper surface of the first semiconductor material layer 40, and specifically includes: the top end of the light absorbing layer 30 is embedded in the first semiconductor material layer 40.
Here, the first portion 45 is an intrinsic layer.
The light absorbing layer 30 further includes a light absorbing doped region 31 within the P-type doped region 42 and the N-type doped region 43. The part of the light absorption doped region 31 located in the P-type doped region 42 is doped P-type; the portion of the light absorbing doped region 31 located within the N-type doped region 43 is N-doped.
In the embodiment shown in fig. 7g, the width of the light absorption layer 30 ranges from 600nm to 1200nm, and the thickness ranges from 300nm to 600 nm. Here, the width of the light absorbing layer 30 specifically refers to the dimension of the light absorbing layer 30 in the X direction, and since the first direction is the same as the X direction in the present embodiment, the dimension of the light absorbing layer 30 specifically in the first direction is 600nm to 1200 nm; the thickness of the light absorbing layer 30 specifically refers to the dimension of the light absorbing layer 30 in the direction perpendicular to the substrate plane, i.e., the dimension in the Z direction, and since the third direction is the same as the Z direction in the present embodiment, the dimension of the light absorbing layer 30 specifically in the third direction is 300nm to 600 nm.
Next, referring to fig. 7h, on the first semiconductor material layer 40, a filling layer 70 is formed.
The material of the fill layer 70 may include silicon dioxide.
In a practical process, the filling layer 70 may be formed by depositing a certain thickness of silicon dioxide material and performing a planarization process.
Then, the method further comprises: forming a first metal electrode 61 and a second metal electrode 62 disposed perpendicular to the substrate plane direction (please refer to the Z direction in fig. 1); said first metal electrode 61 and said second metal electrode 62 are in contact with said P + + doped region 41 and said N + + doped region 44, respectively;
the two metal electrodes can be manufactured by utilizing the processes of photoetching, inductive plasma etching windowing, magnetron sputtering deposition of metal materials and the like.
The upper surfaces of the first metal electrode 61 and the second metal electrode 62 should be higher than the upper surface of the filling layer 70. Specifically, forming a window in the filling layer 70 by using photolithography and etching (such as inductive plasma etching) to expose the P + + doped region 41 and the N + + doped region 44; and filling an electrode material (such as a magnetron sputtering deposition metal material) in the window to form the first metal electrode 61 and the second metal electrode 62.
Fig. 8a-8b are cross-sectional views of device structures in the fabrication process of a photodetector according to another embodiment of the present invention. This embodiment differs from the previous embodiments in that the steps shown in fig. 8a-8b are performed after the photodetector has been prepared using the steps shown in fig. 7a-7 f.
As shown in fig. 8a, after the step shown in fig. 7f is performed, a doping process is performed to form a P-type doped region 42 ', an intrinsic multiplication region 46 and an N-type doped region 43 ' in the first semiconductor material layer 40 '; along the first direction, the light absorption layer 30 'is located in the P-type doped region 42'. Specifically, along the first direction, the P-type doped region 42 'includes portions at both sides of the light absorbing layer 30'.
Here, the P-type doped region 42' may be a P + doped region; the N-type doped region 43' may be an N + doped region.
In a specific embodiment, a P + + doped region 41 ' and an N + + doped region 44 ' may also be formed in the first semiconductor material layer 40 '. The light absorption layer 30 ' is located in the P-type doped region 42 ' of the first semiconductor material layer 40 ', and specifically includes: the light absorbing layer 30' is located within the P + doped region.
The first semiconductor material layer 40 'further includes a portion (see 45' in fig. 8a, hereinafter referred to as "first portion" 45 ') overlying the light absorbing layer 30'. In other words, the upper surface of the light absorption layer 30 'is lower than the upper surface of the first semiconductor material layer 40', and specifically includes: the top end of the light absorbing layer 30 'is embedded in the first semiconductor material layer 40'.
Here, the first portion 45' is an intrinsic layer.
The light absorbing layer 30 ' also includes light absorbing doped regions 31 ' within the P-type doped regions 42 '. The portion of the light-absorbing doped region 31 'located in the P-type doped region 42' is P-type doped. Specifically, both sides of the light absorbing layer 30 'include the light absorbing doped regions 31' along the X direction.
In the embodiment shown in FIG. 8a, the width of the light absorbing layer 30' ranges from 600nm to 1000nm, and the thickness ranges from 200nm to 400 nm. Here, the width of the light absorbing layer 30 ' specifically refers to the dimension of the light absorbing layer 30 ' along the X direction, and since the first direction is the same as the X direction in the present embodiment, the dimension of the light absorbing layer 30 ' specifically along the first direction is 600nm to 1000 nm; the thickness of the light absorbing layer 30 ' specifically refers to the dimension of the light absorbing layer 30 ' in the direction perpendicular to the substrate plane, i.e., the dimension in the Z direction, and since the third direction is the same as the Z direction in the present embodiment, the dimension of the light absorbing layer 30 ' specifically in the third direction is 200nm to 400 nm.
Next, referring to fig. 8b, a filling layer 70 'is formed on the first semiconductor material layer 40'.
The material of the fill layer 70' may include silicon dioxide.
In a practical process, the filling layer 70' may be formed by depositing a certain thickness of silicon dioxide material and performing a planarization process.
Then, the method further comprises: forming a first metal electrode 61 'and a second metal electrode 62' disposed perpendicularly to the substrate plane direction; said first metal electrode 61 'and said second metal electrode 62' are in contact with said P + + doped region 41 'and said N + + doped region 44', respectively;
the two metal electrodes can be manufactured by utilizing the processes of photoetching, inductive plasma etching windowing, magnetron sputtering deposition of metal materials and the like.
The upper surfaces of the first and second metal electrodes 61 ' and 62 ' should be higher than the upper surface of the filling layer 70 '. Specifically, forming a window in the filling layer 70 ' by using a photolithography and etching (e.g., inductive plasma etching) process to expose the P + + doped region 41 ' and the N + + doped region 44 '; and filling an electrode material (such as a magnetron sputtering deposition metal material) in the window to form the first metal electrode 61 'and the second metal electrode 62'.
Thus, the fabrication of the photodetector is substantially completed. Some interconnect processes may be involved later and will not be discussed further herein.
It should be noted that the embodiments of the method for manufacturing the photodetector and the photodetector provided by the embodiments of the present invention belong to the same concept; technical features in technical solutions described in the embodiments may be arbitrarily combined without conflict, and are not described herein again.
The above description is only exemplary of the present application and should not be taken as limiting the scope of the present application, as any modifications, equivalents, improvements, etc. made within the spirit and principle of the present application should be included in the scope of the present application.
Claims (10)
1. A method of fabricating a photodetector, the method comprising:
providing a substrate comprising a first region of semiconductor material;
performing an etching process on the first semiconductor material region to form an optical waveguide structure for transmitting an optical signal; the optical waveguide structure comprises a main waveguide part and a sub-waveguide part which are arranged at intervals along a first direction, the main waveguide part and the sub-waveguide part extend along a second direction, and the first direction is perpendicular to the second direction; in the second direction, a sectional area of the main waveguide portion decreases, and a sectional area of the sub waveguide portion increases; the secondary waveguide portion includes a first secondary waveguide portion and a second secondary waveguide portion, the first secondary waveguide portion and the second secondary waveguide portion being distributed on both sides of the primary waveguide portion in the first direction; the optical waveguide structure receives an optical signal through the main waveguide part, and the main waveguide part and the auxiliary waveguide part are used for regulating and controlling the mode effective refractive index of the photoelectric detector; the optical signal is transmitted in the second direction in the main waveguide section and the sub-waveguide section; the main waveguide part and the auxiliary waveguide part are both provided with a bent waveguide structure;
forming a light absorption layer on the optical waveguide structure for detecting the optical signal transmitted in the optical waveguide structure.
2. The method of claim 1, wherein the substrate comprises a silicon-on-insulator substrate, and the first region of semiconductor material is a region on a top silicon layer of the silicon-on-insulator substrate;
the performing of the etching process on the first semiconductor material region specifically includes: and performing an etching process on the top silicon layer to form the optical waveguide structure.
3. The method according to claim 1, wherein an end surface area of the first sub waveguide portion and an end surface area of the second sub waveguide portion are each smaller than an end surface area of the main waveguide portion at an end of the optical waveguide structure that receives the optical signal.
4. The method of manufacturing a photodetector according to claim 1,
the radius of the curved waveguide structure is greater than or equal to 10 μm.
5. The method of manufacturing a photodetector according to claim 1,
the distance between two sides of the optical waveguide structure along the first direction is larger than or equal to the size of the light absorption layer along the first direction.
6. The method of manufacturing a photodetector according to claim 1,
after forming the optical waveguide structure, the method further comprises: forming a cladding layer covering the optical waveguide structure;
forming a transition layer on the covering layer, wherein the material of the transition layer is a composite material of a first semiconductor material and a second semiconductor material;
forming the light absorption layer specifically includes: and epitaxially growing a second semiconductor material on the transition layer to form the light absorption layer.
7. The method of manufacturing a photodetector according to claim 1,
forming the light absorption layer specifically includes: forming the light absorbing layer by epitaxially growing a second semiconductor material;
after forming the light absorbing layer, the method further comprises:
forming a first semiconductor material layer by epitaxially growing a first semiconductor material, the first semiconductor material layer covering at least two sidewalls of the light absorbing layer in the first direction;
performing a doping process to form a P-type doped region and an N-type doped region in the first semiconductor material layer; along the first direction, the light absorption layer is located between the P-type doped region and the N-type doped region.
8. The method of manufacturing a photodetector according to claim 1,
forming the light absorption layer specifically includes: forming the light absorbing layer by epitaxially growing a second semiconductor material;
after forming the light absorbing layer, the method further comprises:
forming a first semiconductor material layer by epitaxially growing a first semiconductor material, the first semiconductor material layer covering at least two sidewalls of the light absorbing layer in the first direction;
performing a doping process to form a P-type doped region, an intrinsic multiplication region and an N-type doped region in the first semiconductor material layer; along the first direction, the light absorption layer is located in the P-type doped region.
9. The method of manufacturing a photodetector according to claim 1,
forming the light absorption layer specifically includes: forming the light absorbing layer by epitaxially growing a second semiconductor material;
after forming the light absorbing layer, the method further comprises:
and forming a first semiconductor material layer by epitaxial growth, wherein the first semiconductor material layer covers two side walls of the light absorption layer along the first direction and the upper surface of the light absorption layer.
10. The method of any one of claims 6 to 9, wherein the first semiconductor material is silicon; the second semiconductor material is germanium.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202110010821.3A CN112331744B (en) | 2021-01-06 | 2021-01-06 | Preparation method of photoelectric detector |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202110010821.3A CN112331744B (en) | 2021-01-06 | 2021-01-06 | Preparation method of photoelectric detector |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN112331744A CN112331744A (en) | 2021-02-05 |
| CN112331744B true CN112331744B (en) | 2021-11-05 |
Family
ID=74302436
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202110010821.3A Active CN112331744B (en) | 2021-01-06 | 2021-01-06 | Preparation method of photoelectric detector |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN112331744B (en) |
Families Citing this family (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN113035982B (en) * | 2021-03-03 | 2022-09-02 | 中国电子科技集团公司第三十八研究所 | All-silicon-doped multi-junction electric field enhanced germanium optical waveguide detector |
| CN113284963B (en) * | 2021-04-22 | 2021-12-03 | 北京邮电大学 | Interdigital guided mode photoelectric detector |
| CN114256375B (en) * | 2021-12-29 | 2023-08-08 | 武汉光谷信息光电子创新中心有限公司 | Avalanche photodetector and preparation method thereof |
| CN117334777A (en) * | 2021-12-30 | 2024-01-02 | 淮阴工学院 | Method for manufacturing photoelectric detector integrated with double absorption regions |
| CN116500721B (en) * | 2023-06-27 | 2023-10-24 | 北方集成电路技术创新中心(北京)有限公司 | Semiconductor structure and forming method thereof |
Citations (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP1107318A2 (en) * | 1999-12-10 | 2001-06-13 | Nec Corporation | Semiconductor photodetector |
| JP2010225893A (en) * | 2009-03-24 | 2010-10-07 | Nec Corp | Semiconductor light receiving element, method of manufacturing the same, optical wiring, and optical-wireless conversion module |
| CN107768459A (en) * | 2017-10-24 | 2018-03-06 | 超晶科技（北京）有限公司 | Laser and detector of a kind of indium phosphorus nitrogen bismuth material and preparation method thereof and use material and preparation method thereof |
| CN110931575A (en) * | 2019-10-24 | 2020-03-27 | 重庆邮电大学 | Waveguide photodetector monolithically integrated with DBR cladding and reflector |
| CN111211182A (en) * | 2018-11-19 | 2020-05-29 | 上海新微技术研发中心有限公司 | Waveguide type photoelectric detector and manufacturing method thereof |
| CN111933742A (en) * | 2020-07-30 | 2020-11-13 | 武汉光谷信息光电子创新中心有限公司 | Avalanche photodetector and preparation method thereof |
Family Cites Families (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| KR100547777B1 (en) * | 2003-06-03 | 2006-01-31 | 삼성전자주식회사 | Optical detection device using optical waveguide having horizontal light restraint and manufacturing method thereof |
| US9755096B2 (en) * | 2014-03-10 | 2017-09-05 | Elenion Technologies, Llc | Lateral Ge/Si avalanche photodetector |
-
2021
- 2021-01-06 CN CN202110010821.3A patent/CN112331744B/en active Active
Patent Citations (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP1107318A2 (en) * | 1999-12-10 | 2001-06-13 | Nec Corporation | Semiconductor photodetector |
| JP2010225893A (en) * | 2009-03-24 | 2010-10-07 | Nec Corp | Semiconductor light receiving element, method of manufacturing the same, optical wiring, and optical-wireless conversion module |
| CN107768459A (en) * | 2017-10-24 | 2018-03-06 | 超晶科技（北京）有限公司 | Laser and detector of a kind of indium phosphorus nitrogen bismuth material and preparation method thereof and use material and preparation method thereof |
| CN111211182A (en) * | 2018-11-19 | 2020-05-29 | 上海新微技术研发中心有限公司 | Waveguide type photoelectric detector and manufacturing method thereof |
| CN110931575A (en) * | 2019-10-24 | 2020-03-27 | 重庆邮电大学 | Waveguide photodetector monolithically integrated with DBR cladding and reflector |
| CN111933742A (en) * | 2020-07-30 | 2020-11-13 | 武汉光谷信息光电子创新中心有限公司 | Avalanche photodetector and preparation method thereof |
Also Published As
| Publication number | Publication date |
|---|---|
| CN112331744A (en) | 2021-02-05 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| CN112331744B (en) | Preparation method of photoelectric detector | |
| CN111933742B (en) | Avalanche photodetector and preparation method thereof | |
| US8817354B2 (en) | Optical device having reduced optical leakage | |
| JP5232981B2 (en) | SiGe photodiode | |
| US7800193B2 (en) | Photodiode, method for manufacturing such photodiode, optical communication device and optical interconnection module | |
| EP2888619B1 (en) | Method and apparatus for reducing signal loss in a photo detector | |
| US8467637B2 (en) | Waveguide path coupling-type photodiode | |
| US8723125B1 (en) | Waveguide end-coupled infrared detector | |
| CN111628036B (en) | Photoelectric detector with resonant waveguide structure | |
| CN112018211B (en) | Avalanche photodetector and preparation method thereof | |
| CN110880539B (en) | Waveguide integrated avalanche photodiode | |
| US7736927B2 (en) | Method for the production of an anti-reflecting surface on optical integrated circuits | |
| CN108828797B (en) | Silicon-based electro-absorption modulator and preparation method thereof | |
| CN110896112B (en) | Waveguide integrated GeSn photoelectric detector and manufacturing method thereof | |
| CN112038441A (en) | Waveguide-coupled silicon-based photoelectric detector and preparation method thereof | |
| US10942315B2 (en) | Reducing back reflection in a photodiode | |
| EP3961727A2 (en) | Diode with light-sensitive intrinsic region | |
| WO2008080428A1 (en) | Waveguide photodetector in germanium on silicon | |
| CN112331727B (en) | Photoelectric detector | |
| CN105932077A (en) | Silicon infrared optical detector structure and manufacturing method therefor | |
| CN114400267B (en) | Photoelectric detector integrated with double absorption areas and preparation method thereof | |
| US20220131017A1 (en) | In-situ cap for germanium photodetector | |
| WO2012054436A1 (en) | Three dimensional solar power systems and methods of making same | |
| CN113471325A (en) | Silicon-based detector with asymmetric junction and preparation method thereof | |
| CN114497265A (en) | Avalanche photoelectric detector |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PB01 | Publication | ||
| PB01 | Publication | ||
| SE01 | Entry into force of request for substantive examination | ||
| SE01 | Entry into force of request for substantive examination | ||
| GR01 | Patent grant | ||
| GR01 | Patent grant |