WO2017063330A1

WO2017063330A1 - Spectrometer integrated chip and manufacturing method

Info

Publication number: WO2017063330A1
Application number: PCT/CN2016/075934
Authority: WO
Inventors: 吕苗; 吕金科; 邓盛锋; 冯兴兴; 田中群
Original assignee: 厦门大学
Priority date: 2015-10-14
Filing date: 2016-03-09
Publication date: 2017-04-20
Also published as: CN105222895A

Abstract

A spectrometer integrated chip and manufacturing method, the spectrometer integrated chip comprising: a substrate (10), an arrayed waveguide grating (20), a micromirror (40) array, and a photoelectric detector (30) array. The photoelectric detector (30) array, arrayed waveguide grating (20) and micromirror (40) array are sequentially manufactured on the substrate (10) via a microfabrication technique. An input optical signal enters the arrayed waveguide grating (20), is output from an output waveguide (60) of the arrayed waveguide grating (20) and, via a micromirror array (40) in one-to-one correspondence with the arrayed waveguide grating (20), is transmitted to the photoelectric detector (30) array and converted to an electrical signal. The spectrometer integrated chip integrates existing grating, lens and CCD functions, has a small volume and weight, is appropriate for batch production with microelectronic manufacturing techniques, and has low costs.

Description

Spectrometer integrated chip and manufacturing method thereof

Technical field

The invention relates to the field of micro-instrument technology, and more particularly to a spectrometer chip integrated with an arrayed waveguide grating and a photodetector and a manufacturing method thereof.

Background technique

The spectrometer is capable of measuring the spectral composition of the input light and is a necessary measuring instrument for the production of various illumination sources; it is also an essential component in spectral analysis techniques such as absorption spectroscopy, fluorescence spectroscopy and Raman spectroscopy, in food safety, medical care, and environmental testing. Other fields have broad application prospects.

Spectrometers have many commercial products, mainly composed of lenses, gratings and CCD/CMOS photodetectors. However, these products require expensive optical components and precise optical assembly. In the application, there are disadvantages such as high price and large weight.

Summary of the invention

The object of the present invention is to overcome the deficiencies of the prior art, and to provide a spectrometer chip integrated with an arrayed waveguide grating and a photodetector which is small in size, low in cost, and mass-produced, and a manufacturing method thereof.

The technical solution of the present invention is as follows:

A spectrometer integrated chip, comprising: a substrate and an arrayed waveguide grating processed on the substrate, a photodetector array, a micro mirror array; an output waveguide array of the arrayed waveguide grating; and a micro mirror array and a photodetector array are arranged in one-to-one correspondence; The optical signal enters the arrayed waveguide grating from the input waveguide of the arrayed waveguide grating, and light having a specific wavelength in the optical signal is output from a specific output waveguide corresponding to the specific wavelength in the output waveguide array, and is refracted and transmitted to the photodetector through the micro mirror array. The corresponding photodetector in the array is converted into an electrical signal output.

Advantageously, said arrayed waveguide grating is separated from each other by light of different wavelengths output by each output waveguide, depending on the spectral composition of the optical signal.

Advantageously, the arrayed waveguide grating comprises an optical waveguide lower cladding layer, an optical waveguide core layer, and an optical waveguide upper cladding layer.

Preferably, the output waveguide of the arrayed waveguide grating is provided with a detection window of the photodetector, and an impurity layer opposite to the polarity of the substrate is injected into the detection window, and an anti-reflection layer is disposed on the surface of the detection window, and the anti-reflection layer is disposed on the surface of the detection window. An electrical contact window is disposed on the outer periphery, the impurity layer extends to the electrical contact window, the upper electrode in electrical contact with the impurity layer is disposed in the electrical contact window, and the lower electrode is disposed on the bottom surface of the substrate.

Preferably, the photodetectors each have a photosensitive surface, and light having a specific wavelength in the optical signal is respectively outputted from a specific output waveguide corresponding to a specific wavelength in the output waveguide array, and is refracted and transmitted to the photodetector through the micro mirror array. The photosensitive surface of the corresponding photodetector in the array is converted into an electrical signal output.

A spectrometer integrated chip manufacturing method, the steps comprising: fabricating an arrayed waveguide grating, a photodetector array, and a micromirror array.

Preferably, fabricating the arrayed waveguide grating comprises: forming a silicon dioxide layer as an under cladding of the optical waveguide by oxidation and chemical vapor deposition; forming a silicon oxynitride layer as a core layer of the optical waveguide by plasma enhanced chemical vapor deposition; under a nitrogen atmosphere Annealing is performed; the shape of the arrayed waveguide grating is formed on the optical waveguide core layer by photolithography and inductively coupled plasma etching; and the TEOS silicon oxide layer is formed by low pressure chemical vapor deposition as the cladding of the optical waveguide.

Preferably, fabricating the photodetector array comprises: forming an electrical contact window on the substrate by photolithography and wet etching, forming an upper electrode of the photodetector by photolithography, evaporating metal aluminum and wet etching; evaporating metal on the back side of the substrate Aluminum forms a common lower electrode.

Preferably, the micromirror array comprises: covering the processing mold of the micromirror with the connection position of the output waveguide and the photosensor of the photodetector, and then performing micromirror processing.

Preferably, the processing mold of the micromirror is provided with a molding profile and an injection channel, and the processing die is aligned and bonded on the substrate, and the molding profile covers the end of the output waveguide and the photosensitive surface.

Preferably, when processing the micromirror, the ultraviolet curing optical resin is injected and solidified through the injection channel; after the processing die is uncovered, the surface of the substrate is spin-coated with photoresist, the photoresist on the surface of the micromirror is removed, and the sputtering is performed. The metal shot and strip process forms a reflective layer on the surface of the micromirror.

Preferably, the substrate is a single crystal silicon wafer.

The beneficial effects of the present invention are as follows:

The present invention replaces the prior art reflection/transmission grating and CCD/CMOS photodetector with an arrayed waveguide grating and photodetector array fabricated on the same substrate, and realizes the arrayed waveguide grating by using a microlens array integrated on the same substrate. Optical alignment with the photodetector array. The invention can realize the splitting and convert the optical signal into an electric signal, thereby realizing the chip formation of the spectrometer, and adopting the micro processing technology to realize the mass production, greatly reducing the volume and cost of the spectrometer, and even integrating into a portable device such as a smart phone. Realize new functions such as chemical composition analysis.

DRAWINGS

Figure 1 is a schematic view of the structure of the present invention;

2 is a partially enlarged schematic view showing an output waveguide, a micro mirror array, and a photodetector of an arrayed waveguide grating;

3 is a schematic cross-sectional view of an output waveguide, a micro mirror array, and a photodetector of an arrayed waveguide grating;

In the figure: 10 is a substrate, 20 is an arrayed waveguide grating, 30 is a photodetector, 40 is a micromirror, 50 is an input waveguide, 60 is an output waveguide, 70 is a photosensitive surface, 80 is an optical waveguide lower cladding, 90 is The detection window, 100 is an impurity layer, 110 is an anti-reflection layer, 120 is an optical waveguide core layer, 130 is an optical waveguide cladding layer, 140 is an electrical contact window, 150 is an upper electrode, and 160 is a lower electrode.

detailed description

The present invention will be further described in detail below with reference to the accompanying drawings and embodiments.

Embodiments, as shown in FIG. 1, FIG. 2 and FIG. 3, a spectrometer integrated chip, comprising a substrate 10, an arrayed waveguide grating 20, an array of photodetectors 30, an array of micromirrors 40, an arrayed waveguide grating 20, and a photodetector The array of 30 arrays and micromirrors 40 is processed on the substrate 10. The arrayed waveguide grating 20 includes an input waveguide 50, an array of output waveguides 60, an array of output waveguides 60, and an array of micromirrors 40 are arranged in one-to-one correspondence with the array of photodetectors 30. The optical assembly can convert the light of the output waveguide 60 into an electrical signal.

Arrayed waveguide grating 20 is used to split the input light entering through input waveguide 50 such that light of different specific wavelengths enters different output waveguides 60 of the array of output waveguides 60 for different specific output waveguides 60 to output different specific wavelengths. Light. The optical signal enters the arrayed waveguide grating 20 from the input waveguide 50. Light having a specific wavelength in the optical signal is output from a specific output waveguide 60 corresponding to a specific wavelength in the array of output waveguides 60, and is refracted through the array of micromirrors 40 to photodetection. On the photosensitive surface 70 of the corresponding photodetector 30 in the array of the device 30, as shown in FIG. 2, it is converted into an electrical signal output to realize the function of the spectrometer. Therefore, the intensity of the output signals of the respective photodetector 30 units in the array 30 of photodetectors 30 sequentially represents the intensity of the optical signals of the respective wavelengths of the input light, thereby realizing the function of the spectrometer.

On the substrate 10, the detection window 90 of the photodetector 30 is opened at the end of the output waveguide 60 of the arrayed waveguide grating 20, and an impurity layer 100 having a polarity opposite to that of the substrate 10 is injected into the detection window 90, and is disposed on the surface of the detection window 90. The anti-reflection layer 110 is provided with an electrical contact window 140 on the outer periphery of the anti-reflection layer 110. The impurity layer 100 extends to the electrical contact window 140, and the upper electrode 150 is formed in the electrical contact window 140 to make electrical contact with the impurity layer 100. The photosurface 70 is detected. The lower electrode 160 is provided on the bottom surface of the substrate 10 in the window 90 covered by the anti-reflection layer 110 and not covered by the upper electrode.

According to the chip of the present invention, light of different wavelengths outputted by each output waveguide 60 is separated from each other according to the spectral composition of the optical signal.

A spectrometer integrated chip manufacturing method: the substrate 10 can be selected from a single crystal silicon wafer or other semiconductor substrate material. In this embodiment, the substrate 10 is selected from an N-type epitaxial single crystal silicon wafer, the epitaxial layer has a thickness greater than 10 micrometers, and the epitaxial layer has a doping concentration of less than 5×10 ¹⁴ cm ⁻³ , and the arrayed waveguide grating 20 and the photodetector 30 array are The array of micromirrors 40 are all fabricated on the substrate 10 using microfabrication techniques. The optical waveguide lower cladding layer 80, the optical waveguide core layer 120, and the optical waveguide upper cladding layer 130 are processed on the substrate 10, and the arrayed waveguide grating 20 is formed on the planar structure, as shown in FIG. The processing sequence is: optical waveguide lower cladding 80, photodetector 30, optical waveguide core layer 120, optical waveguide upper cladding layer 130, metal upper electrode 150, metal lower electrode 160, and micromirror 40.

The detection window 90 of the photodetector 30 is opened at the end of the output waveguide 60 of the arrayed waveguide grating 20, and the impurity layer 100 opposite to the polarity of the substrate 10 is injected into the substrate 10 in the detection window 90, and an anti-reflection layer is disposed on the surface of the detection window 90. 110. An electrical contact window 140 is disposed on the outer periphery of the anti-reflection layer 110. The impurity layer 100 extends to the electrical contact window 140, the upper electrode in electrical contact with the impurity layer 100 is disposed in the electrical contact window 140, and the lower electrode is disposed on the bottom surface of the substrate 10.

In this embodiment, the detection window 90 of the photodetector 30 is formed by photolithography and wet etching, and a 500 nm thick P-type impurity layer 100 is formed at the window by ion implantation or boron diffusion process; The wavelength range of the signal forms a silicon dioxide layer of a specific thickness as the anti-reflection layer 110. In the present embodiment, the thickness of the anti-reflection layer 110 is 105 nm.

A 1.5 μm thick silicon oxynitride layer was formed as an optical waveguide core layer 120 by plasma enhanced chemical vapor deposition; an annealing at 800 ° C for 1 hour in a nitrogen atmosphere; and an optical waveguide core by photolithography and inductively coupled plasma etching processes The shape of the arrayed waveguide grating 20 is formed on the layer 120; a 2-micron thick TEOS silicon oxide layer is formed as an optical waveguide upper cladding layer 130 by low pressure chemical vapor deposition.

Forming an electrical contact window 140 of the P-type impurity layer 100 of the photodetector 30 array by photolithography and wet etching, forming an upper electrode 150 of the photodetector 30 by photolithography, evaporating 1 micron thick metal aluminum and wet etching; A 1 m thick metal aluminum is evaporated on the back surface of the silicon substrate 10 to form a common lower electrode 160.

The processing die of the micromirror 40 is overlaid on the connection position of the output waveguide 60 and the photosensitive surface 70 of the photodetector 30, and then processed by the micromirror 40. The processing die of the micromirror 40 is provided with a molding profile and an injection channel, and the processing die is aligned and bonded to the substrate 10, and the molding profile covers the end of the output waveguide 60 and the photosensitive surface 70. When the micromirror 40 is processed, the ultraviolet curable optical resin is injected and cured through the injection channel; after the processing die is uncovered, the surface of the substrate 10 is spin-coated with photoresist, the photoresist on the surface of the micromirror 40 is removed, and the coating is passed through the coating. The process forms a reflective layer on the surface of the micromirror 40.

In this embodiment, a processing mold for fabricating the micromirror 40 is formed on another single crystal silicon substrate. First, a photoresist pattern of a profile formed by the micromirror 40 is formed by a laser photolithography process, and a micrograph connecting the respective patterns is connected. Channel (injection channel). In this embodiment, the cross section of the photoresist is a paraboloid. The PDMS precursor is covered on the substrate, and after the PDMS is cured, the processing die having a parabolic shape and a microchannel is formed.

The processing mold is aligned and bonded to the substrate 10 such that the paraboloid covers the end of the output waveguide 60 and the photosensitive surface 70 of the photodetector 30; the ultraviolet-cured optical resin is injected through the microchannel and cured; and the processing die is uncovered. The surface of the substrate is protected by spin coating, the photoresist at the paraboloid is removed by a photolithography process, 100 nm thick silver is sputtered to form a reflective layer, and the metal reflective layer sputtered elsewhere is removed by a lift-off process, only in the micro The surface of the mirror 40 retains a silver reflective layer.

The above-described embodiments are merely illustrative of the invention and are not intended to limit the invention. Variations, modifications, and the like of the above-described embodiments are intended to fall within the scope of the appended claims.

Industrial applicability

The invention relates to a spectrometer integrated chip and a manufacturing method thereof, and an array waveguide grating, a micro mirror array and a photodetector array are integrated on a substrate. Compared with a conventional spectrometer, the invention integrates the original grating, the lens and the monolith. The function of CCD is small in volume and weight. It can be mass-produced by microelectronics manufacturing technology, with low cost and good industrial applicability.

Claims

A spectrometer integrated chip, comprising: a substrate and an arrayed waveguide grating processed on the substrate, a photodetector array, a micro mirror array; an output waveguide array of the arrayed waveguide grating, a micro mirror array and a photodetector array a corresponding setting; the optical signal enters the arrayed waveguide grating from the input waveguide of the arrayed waveguide grating, and the light having the specific wavelength in the optical signal is respectively outputted from the specific output waveguide corresponding to the specific wavelength in the output waveguide array, and is refracted and transmitted through the micro mirror array. It is converted to an electrical signal output to the corresponding photodetector in the photodetector array.
The spectrometer integrated chip according to claim 1, wherein the arrayed waveguide gratings are separated from each other by light of different wavelengths outputted by each of the output waveguides according to a spectral composition of the optical signals.
The spectrometer integrated chip according to claim 1, wherein the arrayed waveguide grating comprises an optical waveguide lower cladding layer, an optical waveguide core layer, and an optical waveguide upper cladding layer.
The spectrometer integrated chip according to claim 3, wherein the output waveguide of the arrayed waveguide grating is provided with a detection window of the photodetector, and an impurity layer opposite to the polarity of the substrate is injected into the detection window. An anti-reflection layer is disposed on the surface of the detection window, an electrical contact window is disposed on the outer periphery of the anti-reflection layer, the impurity layer extends to the electrical contact window, an upper electrode in electrical contact with the impurity layer is disposed in the electrical contact window, and a lower electrode is disposed on the bottom surface of the substrate.
The spectrometer integrated chip according to claim 4, wherein each of the photodetectors has a photosensitive surface, and light having a specific wavelength in the optical signal is respectively output from a specific output waveguide corresponding to a specific wavelength in the output waveguide array. And being refracted by the micro mirror array to the photosensitive surface of the corresponding photodetector in the photodetector array, and converted into an electrical signal output.
A method of fabricating a spectrometer integrated chip according to claim 1 or 2 or 3 or 4 or 5, characterized in that The steps include: fabricating an arrayed waveguide grating, a photodetector array, and a micromirror array.
The method for fabricating a spectrometer integrated chip according to claim 6, wherein the fabricating the arrayed waveguide grating comprises: forming a silicon dioxide layer as an under cladding of the optical waveguide by oxidation and chemical vapor deposition; using plasma enhanced chemical vapor deposition. The silicon oxynitride layer is used as the optical waveguide core layer; annealing is performed under a nitrogen atmosphere; the shape of the arrayed waveguide grating is formed on the optical waveguide core layer by photolithography and inductively coupled plasma etching; TEOS silicon oxide is formed by low pressure chemical vapor deposition The layer acts as a cladding on the optical waveguide.
The method of fabricating a spectrometer integrated chip according to claim 6 or 7, wherein the fabricating the photodetector array comprises: forming an electrical contact window by photolithography and wet etching on the substrate, by photolithography, evaporating metal aluminum and wet The method of etching forms the upper electrode of the photodetector; the metal aluminum is evaporated on the back side of the substrate to form a common lower electrode.
The method of fabricating a spectrometer integrated chip according to claim 1, wherein the micromirror array comprises: covering the processing mirror of the micromirror with the connection position of the output waveguide and the photosensor of the photodetector, and then performing the micromirror machining.
The method of fabricating a spectrometer integrated chip according to claim 9, wherein the processing mold of the micromirror is provided with a molding contour and an injection channel, and the processing mold is aligned and bonded on the substrate, and the molding contour covers the end of the output waveguide. With a photosensitive surface.
The method for fabricating a spectrometer integrated chip according to claim 9, wherein when the micromirror is processed, the ultraviolet curable optical resin is injected and cured through the injection channel; after the processing die is removed, the surface of the substrate is spin-coated with the photoresist. The photoresist on the surface of the micromirror is removed, and a reflective layer is formed on the surface of the micromirror by a sputtering metal and a lift-off process.
The method of fabricating a spectrometer integrated chip according to claim 6, wherein the substrate is a single crystal silicon wafer.