Photoelectric galvanometer and manufacturing method thereof

Abstract

The invention relates to the technical field of photoelectric galvanometers, and discloses a photoelectric galvanometer and a manufacturing method thereof, and the photoelectric galvanometer comprises a substrate layer and a photoelectric galvanometer layer. The substrate layer comprises a cavity and a substrate; the photoelectric galvanometer layer is arranged on the substrate layer; the length and / or width of the photoelectric galvanometer layer is greater than the length and / or width of the substrate; the photoelectric galvanometer layer comprises a suspension part and a supporting part; the suspension part is arranged on the cavity, and the supporting part is arranged on the substrate; the photoelectric galvanometer layer is used for receiving sound waves, generating sound waves and emitting light. In the on-chip galvanometer, sound wave receiving, sound wave generating and light emitting are achieved only through the photoelectric galvanometer layer, high-power laser is not needed, damage to biological tissue is avoided, safety is improved, and the size is small.

Description

Technical Field

[0001] The present application relates to the technical field of photoelectric galvanometers, and in particular to a photoelectric galvanometer and a method for manufacturing the same. Background Art

[0002] Traditional bulk optical galvanometers are widely used in large-scale equipment such as laser processing, lidar, and photoacoustic imaging, but they are bulky and have limited scalability. In price-sensitive markets, laser galvanometers are relatively expensive and often require a cooling system or energy drive. Furthermore, the high-power thermal effects of lasers pose a potential risk of damaging biological tissue. Furthermore, the laser wavelength selection range is narrow, and multi-frequency lasers are expensive. These factors all limit the application of laser galvanometers.

[0003] On-chip galvanometers are an important development direction in recent years, aiming to integrate galvanometer systems on microchips to achieve more miniaturized, low-power and high-precision optical control. On-chip galvanometers are mainly based on micro-electro-mechanical system (MEMS) technology, which can reduce the galvanometer system to micron or millimeter sizes. Compared with traditional galvanometers, they are extremely small and very suitable for applications in portable devices, miniature imaging systems or compact spaces. They use micromechanical methods to control the movement of the reflector to achieve light beam scanning. MEMS technology also allows on-chip galvanometers to be integrated with other components (such as light sources, detectors, etc.) on a single chip to achieve higher system integration, reduce the need for external optical components, and reduce system complexity.

[0004] With the integration and portability of equipment, existing non-on-chip galvanometers are difficult to use in small portable devices. Laser galvanometers are likely to damage biological tissues and are expensive. Although on-chip galvanometers can be used in small devices, due to the high-power thermal effect of lasers, it is difficult to ensure their safety in biological tissues.

[0005] In summary, there is a need to provide an electro-optical galvanometer and a manufacturing method thereof that can improve safety and has a small size. Summary of the Invention

[0006] To solve the above problems, the present application proposes an electro-optical galvanometer and a manufacturing method thereof.

[0007] In one aspect, the present application provides an electro-optical galvanometer, comprising: a substrate layer and an electro-optical galvanometer layer;

[0008] The substrate layer includes a cavity and a substrate;

[0009] The electro-optical galvanometer layer is on the substrate layer; the length and / or width of the electro-optical galvanometer layer is greater than the length and / or width of the substrate;

[0010] The electro-optical galvanometer layer includes a suspended portion and a supporting portion;

[0011] The suspended portion is on the cavity, and the supporting portion is on the substrate;

[0012] The photoelectric galvanometer layer is used for receiving sound waves, generating sound waves and emitting light.

[0013] Preferably, the electro-optical galvanometer layer comprises: a first conductive layer, a light-emitting layer, a piezoelectric layer and a second conductive layer;

[0014] The first conductive layer, the light emitting layer, the piezoelectric layer and the second conductive layer are sequentially stacked on the substrate from bottom to top.

[0015] Preferably, the second conductive layer includes two top electrodes;

[0016] The two top electrodes are located at two ends of the electro-optical galvanometer layer; and one of the two top electrodes is located on the suspended portion.

[0017] Preferably, the cavity comprises a circle or a polygon.

[0018] Preferably, the suspended portion comprises a circle or a polygon.

[0019] Preferably, the top electrode comprises: a circle or a polygon.

[0020] In a second aspect, the present application proposes a method for manufacturing an electro-optical galvanometer, comprising:

[0021] stacking a first conductive layer, a light-emitting layer, a piezoelectric layer, and a second conductive layer in sequence on the substrate layer;

[0022] patterning the second conductive layer to obtain two top electrodes;

[0023] The substrate layer is subjected to back cavity etching to form a cavity in the substrate layer.

[0024] Preferably, materials of the first conductive layer and the second conductive layer include: conductive silicon, conductive oxide and metal.

[0025] Preferably, the material of the light-emitting layer includes gallium nitride, indium gallium nitride and indium gallium arsenide.

[0026] Preferably, the material of the piezoelectric layer includes: lead zirconate titanate, aluminum nitride and scandium-doped aluminum nitride.

[0027] The advantages of this application are that: in the on-chip galvanometer, only the photoelectric galvanometer layer is relied upon to achieve sound wave reception, sound wave generation and light emission, no high-power laser is required, damage to biological tissue is avoided, safety is improved and the size is small. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Various other advantages and benefits will become apparent to those skilled in the art upon reading the detailed description of the preferred embodiment below. The accompanying drawings are for illustration purposes only and are not to be considered as limiting the present application. The same reference symbols are used throughout the drawings to denote the same components. In the drawings:

[0029] Figure 1 is a schematic diagram of an electro-optical galvanometer provided in this application;

[0030] Figure 2 is a schematic diagram of a top electrode of an electro-optical galvanometer provided in the present application;

[0031] Figure 3 This is a front view schematic diagram of the working state of an electro-optical galvanometer provided by the present application;

[0032] Figure 4 is a schematic diagram of a method for manufacturing an electro-optical galvanometer provided in this application;

[0033] Figure 5 is a schematic diagram of a top electrode in a method for manufacturing an electro-optical galvanometer provided in the present application;

[0034] Figure 6 This is a schematic diagram of a cavity in a method for manufacturing an electro-optical galvanometer provided in this application. DETAILED DESCRIPTION

[0035] Exemplary embodiments of the present disclosure will be described in more detail below with reference to the accompanying drawings. Although exemplary embodiments of the present disclosure are shown in the accompanying drawings, it should be understood that the present disclosure can be implemented in various forms and should not be limited by the embodiments described herein. Rather, these embodiments are provided to enable a more thorough understanding of the present disclosure and to fully convey the scope of the present disclosure to those skilled in the art.

[0036] In the first aspect, in order to solve the above problems, the embodiments of the present application propose an electro-optical galvanometer, such as Figure 1 As shown, it includes: a substrate layer 10 and an electro-optical galvanometer layer 20; the substrate layer 10 includes a cavity 12 and a substrate 11; the electro-optical galvanometer layer 20 is on the substrate layer 10; the length and / or width of the electro-optical galvanometer layer 20 is greater than the length and / or width of the substrate 11; the electro-optical galvanometer layer 20 includes a suspended portion 201 and a supporting portion 202; the suspended portion 201 is on the cavity 12, and the supporting portion 202 is on the substrate 11; the electro-optical galvanometer layer 20 is used to receive sound waves, generate sound waves and emit light.

[0037] The optoelectronic galvanometer in the embodiment of the present application combines a piezoelectric micromachined ultrasonic transducer (PMUT) with an optoelectronic galvanometer through an optoelectronic galvanometer layer.

[0038] The electro-optical galvanometer layer includes a cantilever beam portion, which includes a suspended portion and a supporting portion. The suspended portion and the supporting portion are integrated to form the cantilever beam portion. The suspended portion is only used to represent the portion of the electro-optical galvanometer layer above the cavity.

[0039] The electro-optical galvanometer layer of the embodiment of the present application can be made into different sizes or shapes as needed to achieve amplitude or angle modulation changes, thereby expanding functions.

[0040] like Figure 1 As shown, the electro-optical galvanometer layer includes: a first conductive layer 21, a light-emitting layer 22, a piezoelectric layer 23 and a second conductive layer 24. The first conductive layer 21, the light-emitting layer 22, the piezoelectric layer 23 and the second conductive layer 24 are stacked on the substrate 10 from bottom to top.

[0041] The first conductive layer is used as a bottom electrode layer, the second conductive layer is used to make a top electrode, and the light-emitting layer includes an LED.

[0042] The cantilever beam portion further includes: a first conductive layer, a light emitting layer and a piezoelectric layer.

[0043] like Figure 2 As shown, the second conductive layer 24 includes two top electrodes 241 . The two top electrodes 241 are located at two ends of the electro-galvanometer layer 20 ; one of the two top electrodes 241 is located on the suspended portion 201 .

[0044] The area of the top electrode is 0.7 (70%) of the area of the suspended portion.

[0045] The cavity includes a circle or a polygon.

[0046] The suspended portion includes a circle or a polygon.

[0047] The top electrode includes: circular or polygonal.

[0048] The suspended portion and the cavity can adopt different shapes or sizes according to needs, such as circles of different sizes and combinations of circles, and polygons of different sizes and combinations of polygons.

[0049] The light-emitting layer is patterned to form a light-emitting region (LED light-emitting region). The light-emitting region can be formed into various regular or irregular patterns as needed. The light-emitting region is separated from the top electrode, that is, it does not cover the top electrode.

[0050] like Figure 3As shown, it is a front view schematic diagram of the working state of an embodiment of the present application. When vibrating, there is a certain curvature between the suspended portion and the supporting portion (that is, the cantilever beam portion will have a certain curvature when vibrating). The vibration of the piezoelectric layer is controlled by the top electrode and the bottom electrode layer to generate sound waves, and the vibration generated by the piezoelectric layer due to receiving the sound waves causes the electrical signal to be output through the top electrode and the bottom electrode layer, thereby realizing the reception of sound waves and the generation of sound waves. The length ratio between the suspended portion and the supporting portion is related to the vibration frequency of the cantilever beam portion. The higher the required vibration frequency, the shorter the supporting portion that needs to be retained, and the lower the required vibration frequency, the longer the supporting portion that needs to be retained.

[0051] The embodiments of the present application address the problems of bulk optical galvanometers (non-optical galvanometers) being large in size, difficult to integrate, having severe laser loss and low reconfigurability, as well as the high manufacturing and packaging costs, limited frequency selection and poor biosafety of on-chip laser galvanometers. An optical galvanometer with a cantilever beam structure made of a light-emitting layer based on LEDs and a piezoelectric layer based on piezoelectric materials is proposed, which can improve biocompatibility and frequency selectivity while reducing costs. Through finite element analysis, the embodiments of the present application respectively establish rectangular and circular galvanometer models of different sizes, and different amplitudes can be obtained by applying the same voltage. Therefore, controlling the different shapes of the optical galvanometer layers, suspended portions and cavities can meet different application requirements.

[0052] In the second aspect, according to the embodiment of the present application, a method for manufacturing an electro-optical galvanometer is also proposed, such as Figure 4 、 Figure 5 and Figure 6 Shown, including:

[0053] A first conductive layer 21, a light emitting layer 22, a piezoelectric layer 23 and a second conductive layer 24 are sequentially stacked on the substrate layer 10;

[0054] The second conductive layer is patterned to obtain two top electrodes 241;

[0055] The substrate layer is back-etched to form a cavity in the substrate layer.

[0056] Among them, the light-emitting layer is used to generate an LED light source, and the first conductive layer, the piezoelectric layer, and the second conductive layer are used to form an acoustic transducer. The processes for stacking the first conductive layer, the light-emitting layer, the piezoelectric layer, and the second conductive layer on the substrate layer in sequence include: evaporation, physical vapor deposition (PVD), and chemical vapor deposition (CVD). The processes for patterning the second conductive layer include: evaporation, PVD, and CVD. The processes for back-cavity etching the substrate layer include: deep reactive ion etching (DRIE) and lithography, electroforming, and injection molding (LIGA).

[0057] By sequentially stacking a first conductive layer, a light-emitting layer, a piezoelectric layer, and a second conductive layer, a compatible stacking design is implemented, resulting in an integrated LED light source and acoustic transducer, improving device integration and performance. Compared to traditional laser galvanometers, the standardized MEMS manufacturing process significantly reduces costs and improves process and performance consistency.

[0058] Here, a cavity is formed in the substrate layer by deep silicon etching (back cavity etching).

[0059] Materials of the first conductive layer and the second conductive layer include conductive silicon, conductive oxide, and metal.

[0060] Materials for the light emitting layer include gallium nitride (GaN), indium gallium nitride (InGaN), and indium gallium arsenide (InGaAs).

[0061] The materials of the piezoelectric layer include: lead zirconate titanate (PZT), aluminum nitride (ALN) and scandium-doped aluminum nitride (ScALN).

[0062] Materials of the substrate layer include silicon, silicon-on-insulator (SOI), sapphire and diamond.

[0063] In the method of the present application, in the on-chip galvanometer, only the photoelectric galvanometer layer is relied upon to realize sound wave reception, sound wave generation and light emission. A high-power laser is not required, which avoids damage to biological tissue, improves safety and has a small size. By stacking the first conductive layer, the light-emitting layer, the piezoelectric layer and the second conductive layer in sequence, a stacking compatible design is performed to realize an integrated LED light source and acoustic transducer, thereby improving the device integration, reducing the system volume and improving the use effect. Compared with traditional laser galvanometers, the photoelectric galvanometer layer is prepared by a MEMS standardized process, which greatly reduces the production cost and improves the process consistency and performance consistency. The use of LED light sources can also improve frequency selectivity and does not require a high-power laser, so that biological safety can be taken into account and safety can be improved. Higher integration and higher safety can also expand the application scenarios and have a wide range of applications.

[0064] The above description is merely a preferred embodiment of the present application, but the scope of protection of the present application is not limited thereto. Any changes or substitutions that can be easily conceived by a person skilled in the art within the technical scope disclosed in this application should be included in the scope of protection of the present application. Therefore, the scope of protection of the present application should be based on the scope of protection of the claims.

Claims

1. An electro-optical galvanometer, characterized in that: include: substrate layer and electro-optical galvanometer layer; The substrate layer includes a cavity and a substrate; The electro-optical galvanometer layer is on the substrate layer; The length and / or width of the electro-optical galvanometer layer is greater than the length and / or width of the substrate; The electro-optical galvanometer layer includes a suspended portion and a supporting portion; The suspended portion is on the cavity, and the supporting portion is on the substrate; The photoelectric galvanometer layer is used for receiving sound waves, generating sound waves and emitting light.

2. The photoelectric galvanometer according to claim 1, wherein: The electro-optical galvanometer layer includes: a first conductive layer, a light-emitting layer, a piezoelectric layer, and a second conductive layer; The first conductive layer, the light emitting layer, the piezoelectric layer and the second conductive layer are sequentially stacked on the substrate from bottom to top.

3. The photoelectric galvanometer according to claim 2, wherein: The second conductive layer includes two top electrodes; The two top electrodes are located at two ends of the electro-optical galvanometer layer; and one of the two top electrodes is located on the suspended portion.

4. The photoelectric galvanometer according to claim 1, wherein: The cavity comprises a circular shape or a polygonal shape.

5. The photoelectric galvanometer according to claim 1, wherein: The suspended portion includes a circle or a polygon.

6. The photoelectric galvanometer according to claim 3, wherein: The top electrode includes: a circle or a polygon.

7. A method for manufacturing an electro-optical galvanometer, characterized in that: include: stacking a first conductive layer, a light-emitting layer, a piezoelectric layer, and a second conductive layer in sequence on the substrate layer; patterning the second conductive layer to obtain two top electrodes; The substrate layer is subjected to back cavity etching to form a cavity in the substrate layer.

8. The method for manufacturing an electro-optical galvanometer according to claim 7, wherein: Materials of the first conductive layer and the second conductive layer include conductive silicon, conductive oxide and metal.

9. The method for manufacturing an electro-optical galvanometer according to claim 7, wherein: The materials of the light emitting layer include gallium nitride, indium gallium nitride and indium gallium arsenide.

10. The method for manufacturing an electro-optical galvanometer according to claim 7, wherein: The materials of the piezoelectric layer include lead zirconate titanate, aluminum nitride and scandium-doped aluminum nitride.

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