Waveguide integrated nonvolatile light modulation and detection integrated device

Abstract

The invention, which relates to the technical field of the semiconductor device, discloses a waveguide-integrated nonvolatile light modulation and detection integrated device comprising an optical waveguide transmission layer, a dielectric layer, a narrow-band-gap two-dimensional material layer, a ferroelectric two-dimensional semiconductor material layer, an electrode and a coating layer. The optical waveguide transmission layer is coated with a dielectric layer, and the dielectric layer separates the optical waveguide transmission layer from the narrow-band-gap two-dimensional material layer; a narrow-band-gap two-dimensional material layer, a ferroelectric two-dimensional semiconductor material layer and a coating layer are sequentially arranged in the direction away from the dielectric layer on the optical waveguide transmission layer. The narrow-band-gap two-dimensional material layer and the ferroelectric two-dimensional semiconductor material layer are partially overlapped, and electrodes are respectively arranged on the outer surfaces of the non-overlapped parts of the narrow-band-gap two-dimensional material layer and the ferroelectric two-dimensional semiconductor material layer. The device has an optical waveguide-ferroelectric two-dimensional semiconductor heterojunction hybrid waveguide structure, and can realize non-volatile light modulation and detection integration.

Description

Technical Field

[0001] The present invention relates to the technical field of semiconductor devices, and in particular to a waveguide-integrated non-volatile optical modulation and detection integrated device. Background Art

[0002] Integrated optical technology has gained wide attention from the industry and scientific research community in the fields of optical communications, optical sensing, and optical computing. Integrated optical devices are based on optical waveguides, have high power density, and are small in size. They can achieve ultrafast computing with large bandwidth and low power consumption. Cascaded integrated optical networks have been used in optical neuromorphic computing. In the application of integrated optics, modulators and detectors respectively realize electro-optical signal encoding and photoelectric signal decoding, and are the core components of integrated optoelectronic chips.

[0003] At present, the detector and modulator are realized by two devices respectively. The detector mainly realizes photoelectric conversion based on narrow bandgap semiconductor heterojunction (such as Chinese patent document with publication number CN111952385A, etc.). The photogenerated carriers in the space charge region can be effectively converted into photocurrent, but it is difficult to realize high-speed and efficient optical modulation function based on heterojunction of traditional semiconductor materials; the modulator is mainly based on capacitor structure, which is difficult to realize photoelectric conversion, and as the external bias is withdrawn, the light transmission state will return to the initial state, which greatly increases the power consumption of integrated optoelectronic chips. In addition, the integration process of semiconductors and optical waveguides based on covalent bonds is restricted by factors such as lattice mismatch and inconsistent thermal expansion coefficients, which will not only greatly reduce the performance of the device, but also limit the integration density of the entire link.

[0004] The Chinese patent document with the publication number CN118311791A discloses a non-volatile electro-optic modulator based on ferroelectric doping, comprising an upper electrode, a ferroelectric layer, a semiconductor layer and a waveguide cladding arranged in sequence from top to bottom, wherein an on-chip waveguide is wrapped in the waveguide cladding, and the semiconductor layer covers the upper surface of the on-chip waveguide; a pulse voltage is applied between the upper electrode and the semiconductor layer, so that the ferroelectric layer changes the polarization degree and can be maintained when the power is off, and the semiconductor layer, the upper electrode and the ferroelectric layer together form a ferroelectric capacitor structure, so that the optical refractive index and light absorption of the semiconductor layer are adjustable; the semiconductor layer covers the on-chip waveguide, and the refractive index and light absorption changed by the ferroelectric doping act on the on-chip waveguide to realize the modulation of the optical signal, thereby realizing the multi-level non-volatile modulation function. Although the modulator can realize non-volatile electro-optical modulation, it cannot realize the integration of optical modulation and detection.

[0005] In order to improve the integration density of optoelectronic chips and reduce the power consumption of optoelectronic links, it is urgent to provide a non-volatile integrated optical modulation and detection device. Summary of the invention

[0006] In order to solve the deficiencies in the prior art, the present invention provides a waveguide-integrated non-volatile optical modulation and detection integrated device.

[0007] The specific technical solutions adopted are as follows:

[0008] A waveguide-integrated non-volatile optical modulation and detection integrated device, comprising an optical waveguide transmission layer, a dielectric layer, a narrow bandgap two-dimensional material layer, a ferroelectric two-dimensional semiconductor material layer, an electrode and a cladding layer;

[0009] The optical waveguide transmission layer is coated with a dielectric layer, and the dielectric layer separates the optical waveguide transmission layer from the narrow bandgap two-dimensional material layer;

[0010] Along the direction away from the dielectric layer on the optical waveguide transmission layer, a narrow bandgap two-dimensional material layer, a ferroelectric two-dimensional semiconductor material layer and a cladding layer are arranged in sequence; the narrow bandgap two-dimensional material layer and the ferroelectric two-dimensional semiconductor material layer partially overlap, and electrodes are respectively arranged on the outer surfaces of the non-overlapping parts of the narrow bandgap two-dimensional material layer and the ferroelectric two-dimensional semiconductor material layer; the cladding layer plays the role of isolating from air and protecting, and is used to cover the narrow bandgap two-dimensional material layer, the ferroelectric two-dimensional semiconductor material layer and the dielectric layer.

[0011] Specifically, the device is a non-volatile multifunctional device based on the hybrid integration of optical waveguide-narrow bandgap two-dimensional material / ferroelectric two-dimensional semiconductor heterojunction with integrated light modulation and detection. The interaction between light and two-dimensional materials is increased by the interaction between the two-dimensional material and the transmitted light of the TE0 mode transmitted in the waveguide; the barrier height, depletion layer width, and carrier concentration of the junction region of the heterojunction are regulated by the out-of-plane polarization of the ferroelectric two-dimensional semiconductor; the photoelectric conversion and regulation are realized by the narrow bandgap two-dimensional material; and finally, a high-performance non-volatile multifunctional device is realized.

[0012] The overlapping part of the narrow bandgap two-dimensional material layer and the ferroelectric two-dimensional semiconductor material layer forms a heterojunction structure. It should be noted that there is no need for a chemical reaction between the two layers of materials, they only need to overlap with each other. Since the work functions of the two layers of materials are different, carrier transfer will occur at the interface, forming a heterojunction structure with a space charge region.

[0013] Preferably, the material of the waveguide transmission layer includes silicon, silicon nitride or chalcogenide glass (including but not limited to Ge 23 S7S 70 Or Ge2Sb2Se5, etc.), the waveguide transmission layer realizes single-mode optical signal transmission, and after the dielectric layer covers the optical waveguide transmission layer, a flat surface is provided to facilitate mutual coupling between the narrow bandgap two-dimensional material layer and the ferroelectric two-dimensional semiconductor material layer.

[0014] The material of the dielectric layer includes but is not limited to silicon oxide, aluminum oxide, hafnium oxide, etc.

[0015] Narrow bandgap two-dimensional materials include graphene, black phosphorus or transition metal sulfides, which can absorb photon energy in the communication band and convert it into free carriers to realize the function of photoelectric detection.

[0016] Ferroelectric two-dimensional semiconductor materials are two-dimensional semiconductor materials with out-of-plane ferroelectricity, including In2Se3 or CuInP2S2, etc., which can generate ferroelectric polarization and the ferroelectric polarization state can be regulated by bias.

[0017] Furthermore, the number of electrodes is two, and the two electrodes are connected to an external control circuit for collecting photogenerated carriers and applying electrical signals to change the ferroelectric polarization field and regulate the heterojunction.

[0018] Specifically, the electrode materials include but are not limited to gold, silver, copper, etc.

[0019] Specifically, the coating layer material includes but is not limited to silicon oxide, aluminum oxide, organic photoresist, etc.

[0020] Preferably, the thickness of the optical waveguide transmission layer is 220-400nm; the thickness of the dielectric layer between the optical waveguide transmission layer and the narrow bandgap two-dimensional material layer is 10-50nm; the thickness of the narrow bandgap two-dimensional material layer is 0.34-3.0nm; and the thickness of the ferroelectric two-dimensional semiconductor material layer is 5-50nm.

[0021] The absorption coefficient and refractive index of the narrow-bandgap two-dimensional material layer can be regulated by the polarization field, thus playing the role of an optical modulator; the ferroelectric polarization of the ferroelectric two-dimensional semiconductor material layer can exist stably after the external electric field is removed, thus realizing non-volatile light detection and modulation.

[0022] Compared with the prior art, the present invention has the following beneficial effects:

[0023] (1) The present invention proposes a new solution for realizing non-volatility, light detection, and modulation integrated devices; the non-volatile light modulation and detection integrated device provided by the present invention can improve the integration density of optoelectronic chips and reduce the power consumption of optoelectronic links; it increases the interaction between light and two-dimensional materials through the interaction between the two-dimensional material and the transmitted light of the TE0 mode transmitted in the waveguide, and uses the out-of-plane polarization of the ferroelectric two-dimensional semiconductor to regulate the depletion layer width and carrier concentration of the heterojunction, and uses narrow-bandgap two-dimensional materials to realize photoelectric conversion and regulation; it realizes the integration of light modulation and detection as well as non-volatility, and is a high-performance multifunctional device.

[0024] (2) The waveguide-integrated non-volatile optical modulation and detection integrated device can operate in the optical communication band (OU band). BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1It is a cross-sectional schematic diagram of the waveguide-integrated non-volatile optical modulation and detection integrated device.

[0026] Figure 2 This is a schematic diagram of the structure of a waveguide-integrated non-volatile optical modulation and detection integrated device based on a microring resonator.

[0027] Figure 3 It is a schematic diagram of the structure of a waveguide-integrated non-volatile optical modulation and detection integrated device based on Mach-Zehnder interferometer.

[0028] Figure numerals: 1 optical waveguide transmission layer; 2 dielectric layer; narrow bandgap two-dimensional material layer 3; ferroelectric two-dimensional semiconductor material layer 4; electrode 5; cladding layer 6. DETAILED DESCRIPTION

[0029] In order to make the purpose, features and advantages of the present invention more obvious and easy to understand, the following is a detailed description through specific embodiments. In the following description, many specific details are set forth in order to fully understand the present invention. However, the present invention can be implemented in many other ways different from those described herein, and those skilled in the art can make similar improvements without violating the connotation of the present invention, so the present invention is not limited by the specific embodiments disclosed below. The technical features in each embodiment of the present invention can be combined accordingly without conflicting with each other.

[0030] The operating methods in the following examples without specifying specific conditions are usually carried out under conventional conditions or according to the conditions recommended by the manufacturer. The contents not described in detail in this specification belong to the prior art known to professionals in the field. The experimental materials used in the following examples, unless otherwise specified, can be purchased from conventional biochemical reagent companies.

[0031] like Figure 1 As shown, the structure of the waveguide integrated non-volatile optical modulation and detection integrated device includes an optical waveguide transmission layer 1, a dielectric layer 2, a narrow bandgap two-dimensional material layer 3, a ferroelectric two-dimensional semiconductor material layer 4, two electrodes 5 and a cladding layer 6.

[0032] The optical waveguide transmission layer 1 is coated with a dielectric layer 2, and the dielectric layer 2 separates the optical waveguide transmission layer 1 from the narrow bandgap two-dimensional material layer 3. Along the direction away from the dielectric layer 2 on the optical waveguide transmission layer 1, the narrow bandgap two-dimensional material layer 3, the ferroelectric two-dimensional semiconductor material layer 4 and the cladding layer 6 are arranged in sequence; the narrow bandgap two-dimensional material layer 3 and the ferroelectric two-dimensional semiconductor material layer 4 partially overlap (the overlapping part forms a heterojunction structure), and electrodes 5 are respectively arranged on the outer surfaces of the non-overlapping parts of the narrow bandgap two-dimensional material layer 3 and the ferroelectric two-dimensional semiconductor material layer 4; the cladding layer 6 is used to coat the narrow bandgap two-dimensional material layer 3, the ferroelectric two-dimensional semiconductor material layer 4 and the dielectric layer 2.

[0033] The optical waveguide transmission layer 1 is formed on a low refractive index, transparent substrate. The optical waveguide material silicon, silicon nitride or chalcogenide glass is deposited by molecular beam epitaxy, chemical vapor deposition, thermal evaporation and other processes, and patterned by deep ultraviolet exposure or electron beam exposure, and finally the optical waveguide transmission layer 1 is prepared by ion reactive etching.

[0034] The dielectric layer 2 is coated on the outside of the optical waveguide transmission layer 1 (except Figure 1 As shown, it can also be completely covered), a dielectric layer material silicon oxide is deposited on and around the optical waveguide transmission layer 1, and then polished by chemical mechanical method to obtain a flat surface; the thickness of the optical waveguide transmission layer 1 is 220-400nm, and the thickness of the dielectric layer above the waveguide is 10-50nm;

[0035] The narrow bandgap two-dimensional material layer 3 is transferred to the dielectric layer 2 by transfer technology, and the ferroelectric two-dimensional semiconductor material layer 4 is transferred to the narrow bandgap two-dimensional material layer 3 and the dielectric layer 2 by transfer technology; the thickness of the narrow bandgap two-dimensional material layer 3 is 0.34-3.0nm, and the thickness of the ferroelectric two-dimensional semiconductor material layer 4 is 5-50nm; the narrow bandgap two-dimensional material can be selected from graphene, black phosphorus or transition metal sulfide, and the ferroelectric two-dimensional semiconductor material can be selected from In2Se3 or CuInP2S2.

[0036] Specifically, the electrodes 5 can be metal electrodes, which are respectively on both sides of the optical waveguide transmission layer 1; the two electrodes 5 are connected to an external control circuit for collecting photogenerated carriers, applying electrical signals to change the ferroelectric polarization field, and regulating the heterojunction.

[0037] The coating layer 6 is used to isolate the air and protect the two-dimensional material and the dielectric layer. The coating layer material can be selected from aluminum oxide, etc. There is no coating layer 6 above the electrode 5, and the coating layer 6 is removed by etching.

[0038] The above structure can ensure that the light energy propagating in the optical waveguide is absorbed by the narrow-bandgap two-dimensional material, and the interaction between light and matter is enhanced through the waveguide's potential field. The optical waveguide supports TE0 mode optical signal transmission. The narrow-bandgap two-dimensional material layer 3 absorbs TE0 mode photons and generates free carriers to realize the light detection function. The generated free electrons are transported through the heterojunction and collected by the electrode 5 to form a current; at the same time, by applying a bias voltage to the electrode 5, a polarization electric field is formed in the ferroelectric two-dimensional semiconductor material layer 4. The generated polarization electric field changes the complex refractive index of the narrow-bandgap two-dimensional material layer 3, affects the phase and amplitude of the photons in the optical waveguide, and realizes the modulation of the optical signal. The ferroelectric polarization can still be maintained after the external electric field is removed, so the integrated light detection and modulation device realized is non-volatile.

[0039] Example 1

[0040] Construct non-volatile optical modulation and detection integrated devices based on waveguide integration of microring resonators, such as Figure 2 As shown, the covering layer 6 is not shown.

[0041] The optical waveguide transmission layer 1 includes a straight waveguide along the propagation direction of the optical signal and a ring waveguide coupled to the side of the straight waveguide, which is made of silicon material, and the dielectric layer 2 is made of silicon oxide. The total thickness of the optical waveguide transmission layer 1 and the dielectric layer 2 thereon is 230nm (the thickness of the dielectric layer 2 between the optical waveguide transmission layer 1 and the narrow bandgap two-dimensional material layer 3 is 20nm), and the narrow bandgap two-dimensional material layer 3 (thickness is 0.34nm) and the ferroelectric two-dimensional semiconductor material layer 4 (thickness is 20nm) are above the ring waveguide and across the waveguide, wherein the overlapping area of ​​the two layers of two-dimensional material is directly above the optical waveguide, so as to realize the strong interaction between light and two-dimensional material. The electrode 5 is a metal electrode, which is located on the outer surface of the non-overlapping part of the narrow bandgap two-dimensional material layer 3 and the ferroelectric two-dimensional semiconductor material layer 4.

[0042] The narrow bandgap two-dimensional material layer 3 uses graphene, which can absorb the energy of photons in the communication band and convert them into free carriers to realize the function of a light detector; and the refractive index and absorption coefficient of graphene can be changed by an external electric field to realize the function of a modulator; the ferroelectric two-dimensional semiconductor material layer 4 uses In2Se3, and the out-of-plane ferroelectric polarization of In2Se3 can be changed by an external voltage. The generated ferroelectric polarization will change the Fermi level of graphene, regulate the refractive index and absorption coefficient of graphene, and change the phase and loss of photons in the ring waveguide, thereby realizing an integrated detection and modulation device. In addition, the ferroelectric polarization of In2Se3 can still be maintained after the external bias is removed, and the realized device is non-volatile.

[0043] Example 2

[0044] Construct a waveguide-integrated non-volatile optical modulation and detection integrated device based on Mach-Zehnder interferometer, such as Figure 3 As shown, the covering layer 6 is not shown.

[0045] A heterojunction consisting of a narrow bandgap two-dimensional material layer 3 and a ferroelectric two-dimensional semiconductor material layer 4 is integrated on one arm of the Mach-Zehnder interferometer. The optical waveguide transmission layer 1 is made of silicon nitride material, the dielectric layer 2 is made of silicon oxide material, the total thickness of the optical waveguide transmission layer 1 and the dielectric layer 2 thereon is 410nm (the thickness of the dielectric layer 2 between the optical waveguide transmission layer 1 and the narrow bandgap two-dimensional material layer 3 is 20nm), the narrow bandgap two-dimensional material layer 3 (thickness is 2nm) and the ferroelectric two-dimensional semiconductor material layer 4 (thickness is 10nm) are above the ring waveguide and across the waveguide to achieve strong interaction between light and two-dimensional materials. The electrode 5 is a metal electrode, located on the outer surface of the non-overlapping portion of the narrow bandgap two-dimensional material layer 3 and the ferroelectric two-dimensional semiconductor material layer 4.

[0046] The narrow-bandgap two-dimensional material is black phosphorus, which can absorb the energy of photons in the communication band and convert them into free carriers to realize the light detection function. The ferroelectric two-dimensional semiconductor material is CuInP2S2. The out-of-plane ferroelectric polarization of CuInP2S2 can be changed by applying an external voltage. The generated ferroelectric polarization will change the carrier concentration of black phosphorus, regulate the refractive index and absorption coefficient of black phosphorus, change the amplitude and phase of the light energy in the waveguide, and then affect the final output light intensity, realizing an integrated detection and modulation device. In addition, the ferroelectric polarization of CuInP2S2 can still be maintained after the external bias is removed, and the realized device is non-volatile.

[0047] The embodiments described above provide a detailed description of the technical solutions of the present invention. It should be understood that the above are only specific embodiments of the present invention and are not intended to limit the present invention. Any modifications, supplements or similar substitutions made within the scope of the principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A waveguide-integrated non-volatile optical modulation and detection integrated device, characterized in that: It comprises an optical waveguide transmission layer (1), a dielectric layer (2), a narrow bandgap two-dimensional material layer (3), a ferroelectric two-dimensional semiconductor material layer (4), an electrode (5) and a cladding layer (6); The optical waveguide transmission layer (1) is coated with a dielectric layer (2), and the dielectric layer (2) separates the optical waveguide transmission layer (1) from the narrow bandgap two-dimensional material layer (3); A narrow bandgap two-dimensional material layer (3), a ferroelectric two-dimensional semiconductor material layer (4) and a cladding layer (6) are sequentially arranged along a direction away from a dielectric layer (2) on an optical waveguide transmission layer (1); The narrow-bandgap two-dimensional material layer (3) and the ferroelectric two-dimensional semiconductor material layer (4) partially overlap, and electrodes (5) are respectively arranged on the outer surfaces of the non-overlapping parts of the narrow-bandgap two-dimensional material layer (3) and the ferroelectric two-dimensional semiconductor material layer (4); the coating layer (6) plays the role of isolating from air and providing protection.

2. The waveguide integrated non-volatile optical modulation and detection integrated device according to claim 1, characterized in that: The material of the waveguide transmission layer (1) includes silicon, silicon nitride or chalcogenide glass, and the chalcogenide glass includes Ge 23 S7S 70 or Ge2Sb2Se5.

3. The waveguide integrated non-volatile optical modulation and detection integrated device according to claim 1, characterized in that: The material of the dielectric layer (2) includes silicon oxide, aluminum oxide or hafnium oxide.

4. The waveguide integrated non-volatile optical modulation and detection integrated device according to claim 1, characterized in that: Narrow bandgap 2D materials include graphene, black phosphorus or transition metal sulfides.

5. The waveguide integrated non-volatile optical modulation and detection integrated device according to claim 1, characterized in that: Ferroelectric two-dimensional semiconductor materials are two-dimensional semiconductor materials with out-of-plane ferroelectricity, including In2Se3 or CuInP2S2.

6. The waveguide integrated non-volatile optical modulation and detection integrated device according to claim 1, characterized in that: The number of electrodes (5) is two, and the two electrodes (5) are connected to an external control circuit.

7. The waveguide integrated non-volatile optical modulation and detection integrated device according to claim 1, characterized in that: The cladding layer materials include silicon oxide, aluminum oxide or organic photoresist.

8. The waveguide integrated non-volatile optical modulation and detection integrated device according to claim 1, characterized in that: The thickness of the optical waveguide transmission layer (1) is 220-400 nm; the thickness of the dielectric layer (2) between the optical waveguide transmission layer (1) and the narrow bandgap two-dimensional material layer (3) is 10-50 nm; the thickness of the narrow bandgap two-dimensional material layer (3) is 0.34-3.0 nm; and the thickness of the ferroelectric two-dimensional semiconductor material layer (4) is 5-50 nm.

9. Application of the waveguide-integrated non-volatile optical modulation and detection integrated device according to any one of claims 1 to 8 in the fields of optics, electronics or optoelectronics.

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