阅读说明：本技术 波导型GePb红外光电探测器及其制造方法 (Waveguide type GePb infrared photoelectric detector and manufacturing method thereof ) 是由 汪巍 方青 涂芝娟 曾友宏 蔡艳 王庆 王书晓 余明斌 于 2019-03-28 设计创作，主要内容包括：本发明涉及光电子技术领域,尤其涉及一种波导型GePb红外光电探测器及其制造方法。所述波导型GePb红外光电探测器,包括硅衬底以及均位于所述硅衬底表面的波导层和器件结构；所述器件结构包括沿垂直于所述硅衬底的方向依次叠置的下接触层、吸收层和上接触层,所述吸收层的材料为Ge<Sub>1-x</Sub>Pb<Sub>x</Sub>,其中,0<x<1；所述波导层中的光信号通过倏逝波耦合进入所述器件结构。本发明使得光电探测器在短波红外到中波红外波段都能实现高效吸收。(The invention relates to the technical field of photoelectrons, in particular to a waveguide type GePb infrared photoelectric detector and a manufacturing method thereof. The waveguide type GePb infrared photoelectric detector comprises a silicon substrate, a waveguide layer and a device structure, wherein the waveguide layer and the device structure are positioned on the surface of the silicon substrate; the device structure comprises a lower contact layer, an absorption layer and an upper contact layer which are sequentially stacked in the direction perpendicular to the silicon substrate, wherein the absorption layer is made of Ge 1‑x Pb x Wherein, 0<x<1; the above-mentionedOptical signals in the waveguide layer are coupled into the device structure by evanescent waves. The invention enables the photoelectric detector to realize high-efficiency absorption in the short-wave infrared to medium-wave infrared bands.)

1. A waveguide type GePb infrared photoelectric detector is characterized by comprising a silicon substrate, a waveguide layer and a device structure, wherein the waveguide layer and the device structure are positioned on the surface of the silicon substrate; the device structure comprises a lower contact layer, an absorption layer and an upper contact layer which are sequentially stacked along the direction perpendicular to the silicon substrate, wherein the absorption layer is made of a materialGe_1-xPb_xWherein, 0<x<1; the optical signal in the waveguide layer is coupled into the device structure by evanescent waves.

2. The waveguiding GePb infrared photodetector of claim 1, wherein the device structure further comprises:

a first buffer layer between the lower contact layer and the absorber layer;

a second buffer layer between the absorber layer and the upper contact layer.

3. The waveguide type GePb infrared photodetector of claim 2, wherein the first buffer layer and the second buffer layer are both Ge or SiGe.

4. The waveguide type GePb infrared photodetector of claim 1, wherein the material of the waveguide layer is silicon; the lower contact layer is made of a silicon material with first doped ions; the material of the upper contact layer is Ge material with second doping ions, and the second doping ions are opposite to the first doping ions in conduction type.

5. The waveguide-type GePb infrared photodetector of claim 1, wherein 0.001< x < 0.02.

6. A manufacturing method of a waveguide type GePb infrared photoelectric detector is characterized by comprising the following steps:

providing a silicon substrate;

forming a waveguide layer on the surface of the silicon substrate;

forming a device structure on the surface of the silicon substrate, wherein the device structure comprises a lower contact layer, an absorption layer and an upper contact layer which are sequentially stacked along the direction vertical to the silicon substrate, and the absorption layer is made of Ge_1-xPb_xWherein, 0<x<1; the optical signal in the waveguide layer is coupled into the waveguide layer by evanescent waveThe device structure is described.

7. The method of manufacturing a waveguide-type GePb infrared photodetector according to claim 6, wherein the silicon substrate includes a bottom layer silicon, a buried oxide layer, and a top layer silicon which are stacked in this order along an axial direction thereof; the specific steps for forming the waveguide layer on the surface of the silicon substrate comprise:

and etching the top silicon layer to form the waveguide layer and define a device region in the top silicon layer.

8. The method of claim 7, wherein the step of forming a device structure on the surface of the silicon substrate comprises:

implanting first doping ions into the device region to form the lower contact layer;

forming a first buffer layer on the lower contact surface;

forming an absorption layer on the surface of the first buffer layer;

forming a second buffer layer on the surface of the absorption layer;

and forming an upper contact layer on the surface of the second buffer layer.

9. The method of claim 8, wherein the step of forming an absorption layer on the surface of the lower contact layer comprises:

depositing a Ge material on the surface of the lower contact layer to form a pre-absorption layer;

injecting Pb ions from the surface of the pre-absorption layer, which is far away from the lower contact layer, and forming Ge as the material_1-xPb_xThe absorbing layer of (1).

10. The method of claim 6, wherein 0.001< x < 0.02.

Technical Field

The invention relates to the technical field of photoelectrons, in particular to a waveguide type GePb infrared photoelectric detector and a manufacturing method thereof.

Background

The photoelectric detector has wide application, covers various fields of military and national economy, and is mainly used for ray measurement and detection, industrial automatic control, photometric measurement and the like in visible light and short wave infrared bands.

The infrared photoelectric detector has wide application in the fields of communication, night vision, guidance, astronomical observation, biomedical treatment and the like. The infrared detectors commonly used today are mainly group iii-v material photodetectors and group ii-v material photodetectors. However, the iii-v materials and ii-v materials have a problem of incompatibility with the Si-based CMOS (Complementary Metal oxide semiconductor) standard process platform, increasing device cost and reducing device reliability.

Compared with the traditional III-V family infrared photoelectric detector and II-V family infrared photoelectric detector, the IV family infrared photoelectric detector is compatible with the Si-based CMOS process in the preparation process, and has the potential advantages of small volume, easy integration, low cost, high performance and the like. Ge photodetectors based On Si substrates or SOI (Silicon On Insulator) substrates have gained wide application in the fields of communications and sensing. However, when the wavelength of a single Ge material is greater than 1.55 micrometers, the absorption coefficient is sharply reduced, so that the Ge photodetector cannot meet the detection requirements of short-wave infrared and even middle-infrared bands, and the detection range of the Ge photodetector is limited. Therefore, a vertical GeSn infrared photodetector has appeared in the prior art, so as to solve the problem that the Ge photodetector cannot meet the detection requirements of short wave infrared and even middle infrared wave bands. However, epitaxial growth of GeSn materials is extremely challenging, limited by the extremely low solid solubility of Sn in Ge.

Therefore, how to widen the detection range of the Ge photodetector is a technical problem to be solved urgently at present.

Disclosure of Invention

The invention provides a waveguide type GePb infrared photoelectric detector and a manufacturing method thereof, which are used for solving the problem that the detection range of the existing Ge photoelectric detector is narrow.

In order to solve the above problems, the present invention provides a waveguide type GePb infrared photodetector, which comprises a silicon substrate, and a waveguide layer and a device structure both located on the surface of the silicon substrate; the device structure comprises a lower contact layer, an absorption layer and an upper contact layer which are sequentially stacked in the direction perpendicular to the silicon substrate, wherein the absorption layer is made of Ge_1-xPb_xWherein, 0<x<1; the optical signal in the waveguide layer is coupled into the device structure by evanescent waves.

Preferably, the device structure further comprises:

a first buffer layer between the lower contact layer and the absorber layer;

a second buffer layer between the absorber layer and the upper contact layer.

Preferably, the first buffer layer and the second buffer layer are both made of Ge or SiGe.

Preferably, the material of the waveguide layer is silicon; the lower contact layer is made of a silicon material with first doped ions; the material of the upper contact layer is Ge material with second doping ions, and the second doping ions are opposite to the first doping ions in conduction type.

Preferably, 0.001< x < 0.02.

In order to solve the above problems, the present invention further provides a method for manufacturing a waveguide type GePb infrared photodetector, comprising the steps of:

providing a silicon substrate;

forming a waveguide layer on the surface of the silicon substrate;

forming a device structure on the surface of the silicon substrate, wherein the device structure comprises a lower contact layer, an absorption layer and an upper contact layer which are sequentially stacked along the direction vertical to the silicon substrate, and the absorption layer is made of Ge_1-xPb_xWherein, 0<x<1; the optical signal in the waveguide layer is coupled into the device structure by evanescent waves.

Preferably, the silicon substrate comprises a bottom layer silicon, a buried oxide layer and a top layer silicon which are sequentially stacked along the axial direction of the silicon substrate; the specific steps for forming the waveguide layer on the surface of the silicon substrate comprise:

and etching the top silicon layer to form the waveguide layer and define a device region in the top silicon layer.

Preferably, the specific steps of forming the device structure on the surface of the silicon substrate include:

implanting first doping ions into the device region to form the lower contact layer;

forming a first buffer layer on the lower contact surface;

forming an absorption layer on the surface of the first buffer layer;

forming a second buffer layer on the surface of the absorption layer;

and forming an upper contact layer on the surface of the second buffer layer.

Preferably, the step of forming the absorption layer on the surface of the lower contact layer comprises:

depositing a Ge material on the surface of the lower contact layer to form a pre-absorption layer;

injecting Pb ions from the surface of the pre-absorption layer, which is far away from the lower contact layer, and forming Ge as the material_1-xPb_xThe absorbing layer of (1).

Preferably, 0.001< x < 0.02.

The invention relates to a waveguide GePb infrared photoelectric detector and a manufacturing method thereof, wherein Ge is arranged in an absorption layer of a device structure_1-xPb_xThe material enables the photoelectric detector to realize high-efficiency absorption in the short-wave infrared to medium-wave infrared bands. Easy integration with Si compared to iii-v infrared photodetectors; compared with the existing Ge photoelectric detector, the photoelectric detector has wider detection range; compared with a vertical incidence type photoelectric detector, the photoelectric detector is easier to integrate with other optical active or passive devices, and has higher detection sensitivity.

Drawings

FIG. 1 is a schematic diagram of the overall structure of a waveguide GePb infrared photodetector according to the embodiment of the present invention;

FIG. 2 is a schematic cross-sectional view of a device structure in a waveguide type GePb infrared photodetector according to an embodiment of the present invention;

FIG. 3 is a flow chart of a method for manufacturing a waveguide type GePb infrared photodetector according to an embodiment of the present invention;

fig. 4A to 4F are schematic cross-sectional views of the main processes of the present embodiment in the process of manufacturing a waveguide type GePb infrared photodetector.

Detailed Description

The following describes in detail specific embodiments of the waveguide type GePb infrared photodetector and the method for manufacturing the same according to the present invention with reference to the accompanying drawings.

The present embodiment provides a waveguide type GePb infrared photodetector, fig. 1 is a schematic diagram of an overall structure of the waveguide type GePb infrared photodetector according to the present embodiment, and fig. 2 is a schematic diagram of a cross section of a device structure in the waveguide type GePb infrared photodetector according to the present embodiment. As shown in fig. 1 and fig. 2, the waveguide type GePb infrared photodetector provided in this embodiment includes a silicon substrate 10, and a waveguide layer 11 and a device structure both located on a surface of the silicon substrate 10; the device structure comprises a lower contact layer 12, an absorption layer 13 and an upper contact layer 14 which are sequentially stacked along a direction perpendicular to the silicon substrate 10, wherein the absorption layer 13 is made of Ge_1-xPb_xWherein, 0<x<1; the optical signal in the waveguide layer 11 is coupled into the device structure by evanescent waves.

Specifically, the silicon substrate 10 is preferably an SOI substrate including a bottom layer silicon 20, a buried oxide layer 21, and a top layer silicon, and the waveguide layer 11 is formed by etching the top layer silicon of the SOI substrate. The waveguide layer 11 may be connected to the lower contact layer 12, and an external optical signal is coupled into the device structure through the waveguide layer 11. In the specific embodiment, the Pb component is introduced into the absorption layer 13, so that on one hand, the detection range of the Ge photoelectric detector can be expanded, and the Ge photoelectric detector can realize high-efficiency absorption in short-wave infrared to medium-wave infrared bands; on the other hand, the detection range of the photoelectric detector can be widened only by introducing a Pb component with a small content, and the Pb component can be injected into the Ge material in the modes of ion injection and the like, so that the limitation of epitaxial growth of the absorption layer in the prior art is broken.

The component of Pb (i.e. the value of x) in the absorption layer 13 can be adjusted by those skilled in the art according to actual needs, so as to adjust the absorption coefficient of the absorption layer 13, so that users can manufacture infrared photodetectors with different detection ranges. The components described in this embodiment refer to mole fractions.

In order to make the detector have a wider detection range, for example, to make the detection range of the infrared photodetector extend to more than 3 μm to adapt to different detection requirements, it is preferable that 0.001< x < 0.02.

In order to reduce the stress inside the device structure, thereby further improving the performance of the infrared photodetector, preferably, the device structure further includes:

a first buffer layer 17 between the lower contact layer 12 and the absorber layer 13;

a second buffer layer 18 located between the absorber layer 13 and the upper contact layer 14.

Because only a small content of Pb component is needed to be introduced in the embodiment, the detection range of the photoelectric detector can be extended. Therefore, the absorption layer 13 may be formed by combining selective epitaxial growth of Ge material with Pb ion implantation.

Preferably, the materials of the first buffer layer 17 and the second buffer layer 18 are both Ge or SiGe. The specific thicknesses of the first buffer layer 17 and the second buffer layer 18 can be selected by those skilled in the art according to actual needs.

Preferably, the material of the waveguide layer 11 is silicon; the material of the lower contact layer 12 is a silicon material with first doping ions; the material of the upper contact layer 14 is a Ge material having second dopant ions, and the second dopant ions are of an opposite conductivity type to the first dopant ions.

The first doped ions are N-type ions, and the second doped ions are P-type ions; or, the first doped ions are P-type ions, and the second doped ions are N-type ions. The first doped ions are N-type ions and the second doped ions are P-type ions. Specifically, the lower contact layer 12 is a silicon material layer doped with N-type ions, and the doping concentration thereof may be 2 × 10¹⁹cm^-3(ii) a The upper contact layer 14 is a Ge material layer doped with P-type ions and having a doping concentration of 2 × 10¹⁹cm^-3(ii) a The first buffer layer 17 is made of Ge or SiGe; the material of the second buffer layer 18 may be Ge or SiGe. The device structure further comprises an N-electrode 16 positioned on the surface of the lower contact layer 12 and a P-electrode 15 positioned on the surface of the upper contact 14. The material of the N-electrode 16 and the P-electrode 15 can be, but is not limited to, metallic aluminum.

Moreover, the present embodiment further provides a method for manufacturing a waveguide type GePb infrared photodetector, fig. 3 is a flow chart of a method for manufacturing a waveguide type GePb infrared photodetector according to the present embodiment, fig. 4A to 4F are schematic cross-sectional views of main processes in a process of manufacturing a waveguide type GePb infrared photodetector according to the present embodiment, and the structure of the waveguide type GePb infrared photodetector manufactured according to the present embodiment can refer to fig. 1 and fig. 2. As shown in fig. 1 to 3 and fig. 4A to 4F, the method for manufacturing a waveguide type GePb infrared photodetector according to the present embodiment includes the following steps:

step S31, a silicon substrate is provided.

Step S32, forming a waveguide layer 11 on the surface of the silicon substrate, as shown in fig. 4B.

Preferably, the silicon substrate includes a bottom layer silicon 20, a buried oxide layer 21 and a top layer silicon 22 stacked in this order along an axial direction thereof, as shown in fig. 4A; the specific steps for forming the waveguide layer 11 on the surface of the silicon substrate include:

the top silicon 22 is etched to form the waveguide layer 11 and define a device region 40 in the top silicon 22, as shown in fig. 4B.

Specifically, the top silicon 22 in the silicon substrate may be etched by using photolithography and dry etching processes to form the waveguide layer 11, and define a device region 40 in the top silicon 22. Wherein the width of the device region 40 is greater than the width of the waveguide layer 11, for example, the width of the waveguide layer 11 is 500nm, and the width of the device region 40 is 10 μm.

Step S33, forming a device structure on the surface of the silicon substrate, wherein the device structure comprises a lower contact layer 12, an absorption layer 13 and an upper contact layer 14 which are sequentially stacked along a direction perpendicular to the silicon substrate, and the absorption layer 13 is made of Ge_{1- x}Pb_xWherein, 0<x<1; the optical signal in the waveguide layer 11 is coupled into the device structure by evanescent coupling, as shown in fig. 2 and 4F.

Preferably, the specific steps of forming the device structure on the surface of the silicon substrate include:

implanting first doping ions into the device region 40 to form the lower contact layer 12;

forming a first buffer layer 17 on the surface of the lower contact layer 12;

forming an absorption layer 13 on the surface of the first buffer layer 17;

forming a second buffer layer 18 on the surface of the absorption layer 13;

forming an upper contact layer 14 on the surface of the second buffer layer 18.

Preferably, the step of forming the absorption layer 13 on the surface of the lower contact layer 12 includes:

depositing a Ge material on the surface of the lower contact layer 12 to form a pre-absorption layer 41, as shown in fig. 4C;

injecting Pb ions from the surface of the pre-absorption layer, which is far away from the lower contact layer, and forming Ge as the material_1-xPb_x The absorbing layer 13 of (a).

The first doped ions are N-type ions and the second doped ions are P-type ions. Specifically, after the device region 40 is defined in the top silicon layer 22, a photolithography process is first used to define the range of the lower contact layer 12 in the device region 40, and then the lower contact layer 12 is formed by ion implantation and high temperature annealing. Wherein the doping concentration of the first doping ions in the lower contact layer 12 is 2 × 10¹⁹cm^-3. Then, a Ge material or a SiGe material is deposited on the surface of the lower contact layer 12 by using a chemical vapor deposition, a physical vapor deposition, or an atomic layer deposition, etc. to form the first buffer layer 17. Then, an absorption region is defined on the surface of the first buffer layer 17 away from the lower contact layer 12 by using a silicon dioxide hard mask, and the Ge material is epitaxially grown on the absorption region by using a chemical vapor deposition method to form the pre-absorption layer 41, as shown in fig. 4C.

Then, injecting Pb ions from the surface of the pre-absorption layer 41, which is far away from the lower contact layer 12, and performing laser annealing to form Ge_1-xPb_xAs shown in fig. 4D. Wherein, the implantation dosage of Pb ions can be 6 × 10¹⁵cm^-2The implantation energy is 40 keV; annealing with 248nm excimer laser with pulse width and number of 23ns and 5 times, and laser energy density of 400mJ/cm²。

Then, depositing a Ge material or a SiGe material on the surface of the absorption layer 13 away from the first buffer layer 17 to form the second buffer layer 18; finally, a P-type Ge material is selectively epitaxially grown on the surface of the second buffer layer 18 to form the upper contact layer 14, as shown in fig. 4E. Wherein, the upper partThe doping concentration of the P-type ions in the contact layer 14 may be 2 x 10¹⁹cm^-3。

Then, depositing a passivation material on the surfaces of the upper contact layer 14 and the lower contact layer 12 to form an anti-reflection layer; etching the anti-reflection layer by adopting photoetching and dry etching processes to form an N-electrode groove exposing the lower contact layer 12 and a P-electrode groove exposing the upper contact layer 14; finally, metal materials are respectively deposited in the N-electrode groove and the P-electrode groove by adopting magnetron sputtering and other processes to form an N-electrode 16 and a P-electrode 15, as shown in FIG. 4F. Wherein the metal material may be, but is not limited to, metallic aluminum.

In order to make the detector have a wider detection range, for example, to make the detection range of the infrared photodetector extend to more than 3 μm to adapt to different detection requirements, it is preferable that 0.001< x < 0.02.

In the waveguide type GePb infrared photoelectric detector and the manufacturing method thereof, Ge is arranged in an absorption layer of a device structure_1-xPb_xThe material enables the photoelectric detector to realize high-efficiency absorption in the short-wave infrared to medium-wave infrared bands. Easy integration with Si compared to iii-v infrared photodetectors; compared with the existing Ge photoelectric detector, the photoelectric detector has wider detection range; compared with a vertical incidence type photoelectric detector, the photoelectric detector is easier to integrate with other optical active or passive devices, and has higher detection sensitivity.

The foregoing is only a preferred embodiment of the present invention, and it should be noted that, for those skilled in the art, various modifications and decorations can be made without departing from the principle of the present invention, and these modifications and decorations should also be regarded as the protection scope of the present invention.