Terahertz focal plane array detector chip and preparation method thereof

Abstract

The invention discloses a terahertz focal plane array detector chip and a preparation method thereof, the chip comprises a Schottky diode pixel and a Crossbar multipath reading structure, and the Schottky diode pixel comprises an ohmic contact part and a Schottky contact part; the Crossbar multi-path reading structure comprises a transverse electrode, a longitudinal electrode and an isolating layer between the transverse electrode and the longitudinal electrode, the transverse electrode and the longitudinal electrode are arranged in a crossed mode, and the isolating layer between the transverse electrode and the longitudinal electrode is located between the transverse electrode and the longitudinal electrode. And the Schottky diode pixel is connected with the Crossbar multi-path read-out structure through a metal wire. According to the terahertz focal plane array detector chip, the problem of multi-path reading of the terahertz focal plane array detector chip is solved, and meanwhile the problems of short circuit and open circuit caused by intersection of transverse and longitudinal electrodes are solved.

Description

Technical Field

[0001] The invention relates to a semiconductor chip and a process technology thereof, and in particular to a terahertz focal plane array detector chip and a preparation method thereof. Background Art

[0002] The terahertz focal plane array detector is a photoelectric detection device based on focal plane array technology, which can efficiently capture electromagnetic signals in the terahertz band. Terahertz waves (0.1Thz-10Thz) are between microwaves and infrared, and have the characteristics of high penetration, non-ionizing radiation, and high resolution. These characteristics make terahertz waves extremely important in the fields of medical imaging, safety detection, astronomical observation, and material analysis. As the internationally recognized detector with the highest sensitivity in the room temperature field, Schottky diodes can be used as the core component of terahertz imaging technology. The development of terahertz focal plane array detectors with Schottky diode pixels will play an important role in promoting the development of the terahertz imaging field. However, in the process of chip development, there are still challenges and bottlenecks in chip manufacturing technology and multi-pixel readout technology. The development cost of terahertz detector chips is relatively high, especially the high-performance compound materials used and the complex manufacturing process adopted greatly increase the production cost. In addition, how to achieve large-scale manufacturing and reduce its manufacturing cost is the key to promoting the practical application of terahertz focal plane technology.

[0003] For terahertz focal plane array detector chips, due to the serious mismatch between the size of the pixel and the size of the CMOS readout circuit, it is quite difficult to read out the response voltage of each pixel on a large scale. There are two solutions. One method is to achieve three-dimensional interconnection by flip-chip welding, and the other method is to directly read out the pixel leads on the chip. The flip-chip welding process is complicated and expensive; and it is difficult to read out large-scale arrays by directly reading out pixels with leads, and the number of pixels is difficult to exceed a thousand pixels. The Crossbar architecture is an interconnected architecture that consists of wires that cross horizontally and vertically on multiple planes to form a network-like structure. Each intersection on the architecture is controlled by a connection point, thereby realizing a flexible link between input and output. This architecture is expected to solve the problem that it is difficult for us to read out large-scale arrays by directly reading out pixels with leads. In order to often use the Crossbar architecture in terahertz focal plane array detector chips, it is necessary to meet the requirements of electrical isolation of horizontal and vertical electrodes in the Crossbar architecture, and solve the problems of short-circuit reading and open circuit caused by the cross-folding of metal horizontal and vertical electrodes. Summary of the invention

[0004] The purpose of the present invention is to provide a terahertz focal plane array detector chip and a preparation method thereof.

[0005] The solution for achieving the purpose of the present invention is: a terahertz focal plane array detector chip, including a Schottky diode pixel and a Crossbar multi-channel readout structure, wherein the Schottky diode pixel includes an ohmic contact and a Schottky contact; the Crossbar multi-channel readout structure includes a horizontal electrode, a vertical electrode, and an isolation layer between the horizontal electrode and the vertical electrode, the horizontal electrode and the vertical electrode are arranged in a cross pattern, and the isolation layer between the horizontal electrode and the vertical electrode is located between the horizontal electrode and the vertical electrode; the Schottky diode pixel and the Crossbar multi-channel readout structure are connected through metal wires.

[0006] Furthermore, the horizontal electrode is manufactured on the substrate through micro-nano processing technology, the isolation layer between the horizontal electrode and the vertical electrode is manufactured on the horizontal electrode through micro-nano processing technology, and the vertical electrode is manufactured on the isolation layer between the horizontal electrode and the vertical electrode through micro-nano processing technology.

[0007] Furthermore, the height of the horizontal electrode is h1=100nm, the height of the isolation layer between the horizontal electrode and the vertical electrode is h3=200nm, the height of the vertical electrode is h2>h1+h3, the height of the Crossbar multi-channel readout structure is h=h1+h2+h3, the width w of the horizontal electrode is equal to the vertical electrode, and h / w≤5 must be satisfied.

[0008] Furthermore, the height of the vertical electrode h2 = 400 nm, and the electrode width w = 10 microns.

[0009] Furthermore, the substrate has a total of four layers, namely, substrate, buffer layer, epitaxial layer, and passivation layer. The bottom layer is the substrate, which is made of indium phosphide. Above the substrate is the buffer layer, which is made of highly doped gallium arsenide. Above the buffer layer is the epitaxial layer, which is made of low-doped gallium arsenide. Above the epitaxial layer is the passivation layer, which is made of silicon dioxide.

[0010] A method for preparing the terahertz focal plane array detector chip, characterized in that it comprises the following steps: The first step is to prepare the lateral electrodes in the Crossbar multi-channel readout structure: the lateral electrodes in the Crossbar multi-channel readout structure are obtained by sequentially performing spin coating of photoresist on the substrate, photolithography using an ultraviolet lithography machine, and magnetron sputtering growth of gold; The second step is to prepare an isolation layer between the horizontal electrode and the vertical electrode in the Crossbar multi-channel readout structure: the isolation layer between the horizontal electrode and the vertical electrode in the Crossbar multi-channel readout structure is obtained by sequentially performing spin coating of photoresist on the substrate, photolithography using an ultraviolet photolithography machine, and PECVD growth of a silicon nitride isolation layer; The third step is to prepare the vertical electrodes in the Crossbar multi-channel readout structure: the vertical electrodes in the Crossbar multi-channel readout structure are obtained by sequentially performing spin coating of photoresist on the substrate, photolithography using an ultraviolet lithography machine, and magnetron sputtering growth of gold; The fourth step is to prepare the ohmic contact of the Schottky diode pixel: the ohmic contact of the Schottky diode is obtained by sequentially performing spin coating of photoresist, photolithography with a UV lithography machine, RIE etching, and magnetron sputtering growth of gold on the substrate; The fifth step is to prepare the Schottky contact of the Schottky diode pixel: the Schottky contact of the Schottky diode is obtained by sequentially performing spin coating of photoresist, photolithography with a UV lithography machine, RIE etching, and magnetron sputtering growth of gold on the substrate; The sixth step is to prepare the metal wires connecting the Crossbar multi-channel readout structure with the Schottky diode pixels: by spin coating photoresist on the substrate, photolithography with a UV photolithography machine, and magnetron sputtering gold growth, the horizontal electrodes of the Crossbar multi-channel readout structure are connected to the ohmic contacts of the Schottky diode using metal wires, and the vertical electrodes of the Crossbar multi-channel readout structure are connected to the Schottky contacts of the Schottky diode using metal wires.

[0011] Furthermore, in the second step, an isolation layer between the horizontal electrode and the vertical electrode in the Crossbar multi-channel readout structure is prepared: the isolation layer between the horizontal electrode and the vertical electrode in the Crossbar multi-channel readout structure is obtained by sequentially performing spin coating of photoresist on the substrate, photolithography by a UV photolithography machine, and PECVD growth of a silicon nitride isolation layer. The specific method is as follows: Spin-coat az1500 photoresist on the substrate surface, transfer the pattern of the isolation layer between the horizontal electrode and the vertical electrode to the photoresist by photolithography, develop the photoresist to obtain the pattern of the isolation layer between the horizontal electrode and the vertical electrode, and grow silicon nitride as the isolation layer between the horizontal electrode and the vertical electrode on the developed pattern of the isolation layer between the horizontal electrode and the vertical electrode by PECVD process, wherein: The PECVD temperature was adjusted to 150 degrees, the gas introduction rates were 80 sccm of silane, 40 sccm of nitrogen, and 120 sccm of nitrous oxide, the reaction power was 10 W, and the reaction time was 400 s.

[0012] Compared with the prior art, the present invention has the following significant advantages: 1) By pre-preparing a crossbar multi-channel readout structure of metal horizontal electrode-insulating layer-metal vertical electrode, an isolation layer between the horizontal and vertical electrodes is successfully prepared, solving the problem of multi-channel readout of the terahertz focal plane array detector chip, while avoiding the short circuit and open circuit problems caused by the crossing between the horizontal and vertical electrodes. 2) The preparation process is simple, and the prepared crossbar multi-channel readout structure does not affect the subsequent preparation and performance of Schottky diode pixels, significantly improving the device yield, and obtaining a 32×32 pixel terahertz focal plane array detector chip and its stable preparation process. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] Figure 1This is the process flow for preparing terahertz focal plane array detector chip.

[0014] Figure 2 Schematic diagram of the terahertz focal plane array chip.

[0015] Figure 3 Schematic diagram of a horizontal electrode in a Crossbar multiple-channel readout structure, an isolation layer between the horizontal electrode and the vertical electrode in the Crossbar multiple-channel readout structure, and a vertical electrode structure in the Crossbar multiple-channel readout structure.

[0016] Figure 4 Schematic diagram of the preparation structure and process flow of the Crossbar multi-channel readout structure, where (a)-(c) correspond to the preparation of the horizontal electrode in the Crossbar multi-channel readout structure, the preparation of the isolation layer between the horizontal electrode and the vertical electrode in the Crossbar multi-channel readout structure, and the preparation of the vertical electrode in the Crossbar multi-channel readout structure.

[0017] Figure 5 Schematic diagram of the preparation structure and process flow of Schottky diode pixels, where (a)-(b) correspond to the ohmic contact preparation in Schottky diode pixels and the Schottky contact preparation in Schottky diode pixels, respectively.

[0018] Figure 6 Schematic diagram of a single pixel and electrode leads in a terahertz focal plane array detector chip.

[0019] Figure 7 This is a picture of the isolation layer between the horizontal electrodes and the horizontal and vertical electrodes in the Crossbar multi-channel readout structure obtained through semiconductor process technology under an optical microscope.

[0020] Figure 8 An arbitrary single-pixel electrical characteristic measurement curve is extracted for the prepared terahertz focal plane array detector chip.

[0021] Figure numerals: 1. horizontal electrode, 2. vertical electrode, 3. isolation layer between the horizontal electrode and the vertical electrode, 4. ohmic contact of Schottky diode pixel, 5. Schottky contact of Schottky diode pixel, 6. metal wire connecting the horizontal electrode of the Crossbar architecture and the ohmic contact of the Schottky diode pixel, 7. metal wire connecting the vertical electrode of the Crossbar architecture and the Schottky contact of the Schottky diode pixel. DETAILED DESCRIPTION

[0022] In order to make the purpose, technical solutions and advantages of this application more clear, the present application is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain this application and are not used to limit this application.

[0023] A terahertz focal plane array detector chip includes two parts: a Schottky diode pixel and a Crossbar multi-channel readout structure. The Schottky diode pixel includes two parts: an ohmic contact and a Schottky contact; the Crossbar multi-channel readout structure includes three parts: a horizontal electrode, a vertical electrode, and an isolation layer between the horizontal electrode and the vertical electrode; the Schottky diode pixel and the Crossbar multi-channel readout structure are connected through metal wires.

[0024] The preparation method includes sequentially preparing a crossbar multi-channel readout structure transverse electrode; preparing an isolation layer between the crossbar multi-channel readout structure transverse electrode and the vertical electrode; preparing the crossbar multi-channel readout structure vertical electrode; preparing an ohmic contact of a Schottky diode pixel; preparing a Schottky contact of the Schottky diode pixel; and preparing a metal wire connecting the Schottky diode pixel and the Crossbar multi-channel readout structure.

[0025] 1. Design of each part of Crossbar architecture: In order to meet the requirements of the present invention, it is first necessary to determine the parameters of the micro-nano processing technology of each component in the Crossbar multi-channel readout structure. Since the Crossbar multi-channel readout structure consists of three parts: a horizontal electrode 1, a vertical electrode 2, and an isolation layer 3 between the horizontal electrode and the vertical electrode, the horizontal electrode 1 is manufactured on a substrate through a micro-nano processing technology, the isolation layer 3 between the horizontal electrode and the vertical electrode is manufactured on the horizontal electrode 1 through a micro-nano processing technology, and the vertical electrode 2 is manufactured on the isolation layer 3 between the horizontal electrode and the vertical electrode through a micro-nano processing technology. Now we need to determine the height h1 of the transverse electrode 1, the height h2 of the longitudinal electrode 2, and the height h3 of the isolation layer 3 between the transverse electrode and the longitudinal electrode. The higher the height, the higher the requirements for the process and the higher the cost. In order to simplify the process and reduce the cost, the heights of the transverse electrode 1, the longitudinal electrode 2, and the isolation layer 3 between the transverse electrode and the longitudinal electrode are designed to be as low as possible. The transverse electrode 1 is the bottom. However, in the micro-nano processing technology, we use photolithography, and the overlay method is used in the photolithography process. When h1 is less than 100nm, it will cause the subsequent manufacture of the longitudinal electrode 2 in the micro-nano manufacturing process. The overlay of photolithography failed during the manufacturing process, so h1≥100nm. In order to ensure a low height, h1=100nm was finally determined. The isolation layer 3 between the horizontal electrode and the vertical electrode is manufactured on the horizontal electrode 1 through a micro-nano processing process. In order to make the horizontal electrode 1 and the vertical electrode 2 conduct electricity normally without a short circuit, the isolation layer 3 between the horizontal electrode and the vertical electrode needs to completely separate the horizontal electrode 1 from the vertical electrode 2. When h3<2×h1, the stress will cause the edge of the isolation layer 3 between the horizontal electrode and the vertical electrode to crack, resulting in a short circuit between the horizontal electrode 1 and the vertical electrode 2. Therefore, in order to avoid stress, h3≥200nm is adopted. In order to ensure a low height, h3=200nm is finally determined. The vertical electrode 2 is manufactured on the isolation layer 3 between the horizontal electrode and the vertical electrode through micro-nano processing technology. When h2h1+h3, that is, h2>300nm. In addition, in order to ensure that the vertical electrode 2 is easier to realize in terms of technology, the electrode height h is greater than the width w (that is, the width of the horizontal electrode and the vertical electrode) in terms of technology. The highest ratio is 5 / 1, that is, h / w≤5. If it is too high, there will be a risk of collapse. Assuming that when h2=400nm, the maximum height of the Crossbar multi-channel readout structure is h=h1+h2+h3=700nm. Since the designed electrode width w=10 microns, at this time and h / w=0.07, it meets the micro-nano processing requirements and is easier to achieve in terms of technology, so h2=400nm is determined. In summary, the height of the horizontal electrode in the Crossbar architecture is determined to be 100nm, the height of the vertical electrode is 400nm, and the height of the isolation layer between the horizontal electrode and the vertical electrode is 200nm.<h1>

[0026] 2. The preparation process of terahertz focal plane array detector chip is as follows Figure 1 As shown: The first step is to prepare the lateral electrodes in the Crossbar multi-channel readout structure: the lateral electrodes in the Crossbar multi-channel readout structure are obtained by sequentially performing spin coating of photoresist on the substrate, photolithography using an ultraviolet lithography machine, and magnetron sputtering growth of gold; specifically: AZ1500 photoresist is spin-coated on the substrate surface, the pattern of the transverse electrode is transferred to the photoresist by photolithography, the photoresist is developed to obtain the pattern of the transverse electrode, and 100 nm of gold is grown on the developed transverse electrode pattern by magnetron sputtering technology as a transverse electrode.

[0027] The second step is to prepare an isolation layer between the horizontal electrode and the vertical electrode in the Crossbar multi-channel readout structure: the isolation layer between the horizontal electrode and the vertical electrode in the Crossbar multi-channel readout structure is obtained by sequentially performing spin coating of photoresist on the substrate, photolithography using an ultraviolet photolithography machine, and PECVD growth of a silicon nitride isolation layer; Az1500 photoresist is spin-coated on the surface of the substrate, and the pattern of the isolation layer between the horizontal electrode and the vertical electrode is transferred to the photoresist by photolithography. The photoresist is developed to obtain the pattern of the isolation layer between the horizontal electrode and the vertical electrode, and 200nm of silicon nitride is grown on the developed pattern of the isolation layer between the horizontal electrode and the vertical electrode by a PECVD process as the isolation layer between the horizontal electrode and the vertical electrode.

[0028] The third step is to prepare the vertical electrodes in the Crossbar multi-channel readout structure: the vertical electrodes in the Crossbar multi-channel readout structure are obtained by sequentially performing spin coating of photoresist on the substrate, photolithography using an ultraviolet lithography machine, and magnetron sputtering growth of gold; AZ1500 photoresist is spin-coated on the surface of the substrate, the pattern of the vertical electrode is transferred to the photoresist by photolithography, the photoresist is developed to obtain the pattern of the vertical electrode, and 400nm of gold is grown as the vertical electrode on the developed vertical electrode pattern by magnetron sputtering technology.

[0029] The fourth step is to prepare the ohmic contact of the Schottky diode pixel: the ohmic contact of the Schottky diode is obtained by sequentially performing spin coating of photoresist, photolithography with a UV lithography machine, RIE etching, and magnetron sputtering growth of gold on the substrate; Az1500 photoresist is spin-coated on the surface of the substrate, and the ohmic contact pattern is transferred to the photoresist by photolithography. The ohmic contact pattern is obtained by developing the photoresist. After the development is completed, the developed ohmic contact pattern is etched by RIE for 4 minutes and 30 seconds. After the etching is completed, 300nm of gold is grown as an ohmic contact on the ohmic contact pattern etched by RIE by magnetron sputtering technology.

[0030] The fifth step is to prepare the Schottky contact of the Schottky diode pixel: the Schottky contact of the Schottky diode is obtained by sequentially performing spin coating of photoresist, photolithography with a UV lithography machine, RIE etching, and magnetron sputtering growth of gold on the substrate; Az1500 photoresist is spin-coated on the surface of the substrate, and the Schottky contact pattern is transferred to the photoresist by photolithography. The Schottky contact pattern is obtained by developing the photoresist. After the development is completed, the developed Schottky contact pattern is etched by RIE for 2 minutes and 30 seconds. After the etching is completed, 300nm of gold is grown on the etched Schottky contact pattern by magnetron sputtering technology as a Schottky contact.

[0031] Step 6: Prepare metal wires connecting the Crossbar multi-channel readout structure and the Schottky diode pixel: by sequentially performing spin coating of photoresist on the substrate, photolithography with an ultraviolet lithography machine, and magnetron sputtering to grow gold, the horizontal electrode of the Crossbar multi-channel readout structure is connected to the ohmic contact of the Schottky diode using a metal wire, and the vertical electrode of the Crossbar multi-channel readout structure is connected to the Schottky contact of the Schottky diode using a metal wire; Az1500 photoresist is spin-coated on the surface of the substrate, and a metal wire pattern connecting the Crossbar multiple-way readout structure and the Schottky diode pixel is transferred to the photoresist by photolithography. The metal wire pattern connecting the Crossbar multiple-way readout structure and the Schottky diode pixel is obtained by developing the photoresist. After the development is completed, 300nm of gold is grown by magnetron sputtering on the metal wire pattern connecting the Crossbar multiple-way readout structure and the Schottky diode pixel obtained by development to serve as the metal wire connecting the Crossbar multiple-way readout structure and the Schottky diode pixel.

[0032] Furthermore, the substrate has four layers in total, namely, substrate, buffer layer, epitaxial layer, and passivation layer. The bottom layer is the substrate, which is made of indium phosphide, the buffer layer is above the substrate, which is made of highly doped gallium arsenide, the epitaxial layer is above the buffer layer, which is made of low-doped gallium arsenide, and the passivation layer is above the epitaxial layer, which is made of silicon dioxide.

[0033] 3. Schematic diagram of terahertz focal plane array detector chip Figure 2 As shown: 1 is the horizontal electrode of the Crossbar multiple readout structure in the terahertz focal plane array detector, 2 is the vertical electrode of the Crossbar multiple readout structure in the terahertz focal plane array detector, and 3 is the isolation layer between the horizontal electrode and the vertical electrode of the Crossbar multiple readout structure in the terahertz focal plane array detector. It can be seen that the horizontal electrode and the vertical electrode are arranged in a cross pattern, and the isolation layer between the horizontal electrode and the vertical electrode is located between the horizontal electrode and the vertical electrode.

[0034] 4. Crossbar multi-channel readout structure in terahertz focal plane array detector Figure 3 As shown: Among them, 1 is the horizontal electrode of the Crossbar multiple-channel readout structure in the terahertz focal plane array detector, 2 is the vertical electrode of the Crossbar multiple-channel readout structure in the terahertz focal plane array detector, and 3 is the isolation layer between the horizontal electrode and the vertical electrode of the Crossbar multiple-channel readout structure in the terahertz focal plane array detector. The horizontal electrode and the vertical electrode are arranged in a cross pattern, and the isolation layer between the horizontal electrode and the vertical electrode is located between the horizontal electrode and the vertical electrode. It can be clearly seen that the height h1 of the horizontal electrode of the Crossbar multiple-channel readout structure is less than the height h3 of the isolation layer between the horizontal electrode and the vertical electrode of the Crossbar multiple-channel readout structure, that is, h1<h3, and the height h2 of the vertical electrode of the Crossbar multiple-channel readout structure is greater than the sum of the height h1 of the horizontal electrode of the Crossbar multiple-channel readout structure and the height h3 of the isolation layer between the horizontal electrode and the vertical electrode of the Crossbar multiple-channel readout structure, that is, h2>h1+h3.

[0035] 5. Crossbar multi-channel readout structure and fabrication process flow in terahertz focal plane array detector Figure 4 As shown: Spin-coat the photoresist on the substrate surface, transfer the pattern of the transverse electrode to the photoresist by photolithography, develop the photoresist to obtain the pattern of the transverse electrode, and grow gold as the transverse electrode on the developed transverse electrode pattern by magnetron sputtering technology. Figure 4 (a); Spin-coating a photoresist on the substrate surface, transferring the pattern of the isolation layer between the horizontal electrode and the vertical electrode to the photoresist by photolithography, developing the photoresist to obtain the pattern of the isolation layer between the horizontal electrode and the vertical electrode, and growing silicon nitride as the isolation layer between the horizontal electrode and the vertical electrode on the pattern of the isolation layer between the horizontal electrode and the vertical electrode obtained by the PECVD process. Figure 4 (b); Spin-coating a photoresist on the substrate surface, transferring the pattern of the vertical electrode to the photoresist by photolithography, developing the photoresist to obtain the pattern of the vertical electrode, and growing gold as the vertical electrode on the developed vertical electrode pattern by magnetron sputtering technology to obtain Figure 4 Middle (c).

[0036] 6. The structure and preparation process of Schottky diode pixels in terahertz focal plane array detectors Figure 5 As shown: Spin-coat the photoresist on the substrate surface, transfer the ohmic contact pattern to the photoresist by photolithography, develop the photoresist to obtain the ohmic contact pattern, and after the development is completed, the developed ohmic contact pattern is etched by RIE. After the etching is completed, gold is grown on the ohmic contact pattern etched by RIE by magnetron sputtering technology as an ohmic contact. Figure 5As shown in (a); a photoresist is spin-coated on the substrate surface, a Schottky contact pattern is transferred to the photoresist by photolithography, a Schottky contact pattern is obtained by developing the photoresist, and after the development is completed, the developed Schottky contact pattern is RIE-etched by RIE, and after the etching is completed, gold is grown on the Schottky contact pattern after the RIE etching by magnetron sputtering technology as a Schottky contact. Figure 5 As shown in (b).

[0037] 7. The structure and preparation process of the metal wires connecting the Crossbar multi-channel readout structure and Schottky diode pixels in the terahertz focal plane array detector Figure 6 As shown: Spin-coat a photoresist on the substrate surface, transfer a metal wire pattern connecting the Crossbar multi-channel readout structure and the Schottky diode pixel to the photoresist by photolithography, develop the photoresist to obtain a metal wire pattern connecting the Crossbar multi-channel readout structure and the Schottky diode pixel, and after the development is completed, magnetron sputtering is performed on the metal wire pattern connecting the developed Crossbar multi-channel readout structure and the Schottky diode pixel to grow gold as a metal wire connecting the Crossbar multi-channel readout structure and the Schottky diode pixel, such as Figure 6 shown.

[0038] 8. Figure 7 This is a picture of the isolation layer between the horizontal electrode and the horizontal and vertical electrodes in the Crossbar multi-channel readout structure obtained through semiconductor process technology under an optical microscope: In the figure, 1 is a horizontal electrode in a Crossbar multi-channel readout structure prepared by semiconductor process technology, which is made of gold, has a height of 100nm, and is relatively clear under a microscope. 3 is an isolation layer between the horizontal electrode and the vertical electrode in a Crossbar multi-channel readout structure prepared by semiconductor process technology, which is made of silicon nitride, has a height of 200nm, and is relatively clear under a microscope.

[0039] 9. Figure 8 To extract any single pixel electrical characteristic measurement curve for the prepared terahertz focal plane array detector chip: The figure shows the voltage-current curve obtained by piercing arbitrary horizontal and vertical electrodes with the probe station and applying a voltage between -1 volt and 1 volt. It can be seen that the obtained voltage-current curve is a more obvious Schottky diode voltage-current curve, and has a good response when the voltage is 1v, proving that the designed Croossbar architecture meets our application in terahertz focal plane array detectors.

[0040] Example

[0041] In order to verify the effectiveness of the invention scheme, the following experiment was conducted.

[0042] like Figure 1 As shown, a terahertz focal plane array detector chip is prepared as follows: 1) Place the substrate on the coating machine and spin-coat the photoresist az1500 on the surface. Adjust the coating machine speed to 4000 rpm for 40 seconds. After the coating is completed, place the substrate on a drying table for drying. Adjust the drying table temperature to 90 degrees for 120 seconds. After drying, send the substrate to the UV photolithography machine for photolithography. Adjust the exposure time of the photolithography machine to 4 seconds, the waiting time to 30 seconds, and the spacing to 23. After the photolithography is completed, use a positive photoresist developer to develop the substrate for 14 seconds. The substrate needs to be shaken during the development process. After the development is completed, send the substrate to the magnetron sputtering. By adjusting the DC magnetron sputtering current to 0.4A, the voltage to 378V, the pressure to 0.376Pa, and the reaction time to 100s, the horizontal electrode in the Crossbar multi-channel readout structure is obtained.

[0043] 2) Place the substrate on the coating machine and spin-coat the photoresist az1500 on the surface. Adjust the coating machine speed to 4000 rpm for 40 seconds. After the coating is completed, place the substrate on a drying table for drying. Adjust the drying table temperature to 90 degrees for 120 seconds. After drying, send the substrate to the UV photolithography machine for photolithography. Adjust the exposure time of the photolithography machine to 4 seconds, the waiting time to 30 seconds, and the spacing to 23. After the photolithography is completed, use a positive photoresist developer to develop the substrate for 14 seconds. The substrate needs to be shaken during the development process. After the development is completed, send the substrate to PECVD. By adjusting the PECVD temperature to 150 degrees, the gas introduction rate is 80 sccm of silane, 40 sccm of nitrogen, and 120 sccm of nitrous oxide, the reaction power is 10w, and the reaction time is 400s, the isolation layer between the horizontal electrode and the vertical electrode in the Crossbar multi-channel readout structure is obtained.

[0044] 3) Place the substrate on the coating machine and spin-coat the photoresist az1500 on the surface. Adjust the coating machine speed to 4000 rpm for 40 seconds. After the coating is completed, place the substrate on a drying table for drying. Adjust the drying table temperature to 90 degrees for 120 seconds. After drying, send the substrate to the UV photolithography machine for photolithography. Adjust the exposure time of the photolithography machine to 4 seconds, the waiting time to 30 seconds, and the spacing to 23. After the photolithography is completed, use a positive photoresist developer to develop the substrate for 14 seconds. The substrate needs to be shaken during the development process. After the development is completed, send the substrate to the magnetron sputtering. By adjusting the DC magnetron sputtering current to 0.8A, the voltage to 378V, the pressure to 0.376Pa, and the reaction time to 400s, the vertical electrodes in the Crossbar multi-channel readout structure are obtained.

[0045] 4) Place the substrate on the coating machine and spin-coat the photoresist az1500 on the surface. Adjust the coating machine speed to 4000 rpm for 40 seconds. After the coating is completed, place the substrate on the drying table for drying. Adjust the drying table temperature to 90 degrees for 120 seconds. After the drying is completed, send the substrate to the UV lithography machine for photolithography. Adjust the exposure time of the lithography machine to 4 seconds, the waiting time to 30 seconds, and the spacing to 23. After the photolithography is completed, use positive photoresist developer to etch the substrate. The development was carried out for 14 seconds. The substrate needed to be shaken during the development process. After the development was completed, the substrate was sent to RIE for etching. The etching gas rate was 30 sccm of carbon tetrafluoride and 10 sccm of oxygen. The power was 150 W and the time was 4 minutes and 30 seconds. After the etching was completed, the substrate was sent to magnetron sputtering. By adjusting the DC magnetron sputtering current to 0.4 A, the voltage to 378 V, the pressure to 0.376 Pa, and growing for 300 seconds, the ohmic contact of the Schottky diode pixel was obtained.

[0046] 5) Place the substrate on the coating machine and spin-coat the photoresist az1500 on the surface. Adjust the coating machine speed to 4000 rpm for 40 seconds. After the coating is completed, place the substrate on the drying table for drying. Adjust the drying table temperature to 90 degrees for 120 seconds. After the drying is completed, send the substrate to the UV lithography machine for photolithography. Adjust the exposure time of the lithography machine to 4 seconds, the waiting time to 30 seconds, and the spacing to 23. After the photolithography is completed, use the positive photoresist developer to treat the substrate. The development takes 14 seconds, and the substrate needs to be shaken during the development process. After the development is completed, the substrate is sent to RIE for etching. The etching gas rate is 30 sccm of carbon tetrafluoride and 10 sccm of oxygen. The power is 150w and the time is 2 minutes and 30 seconds. After the etching is completed, the substrate is sent to magnetron sputtering. By adjusting the DC magnetron sputtering current to 0.4A, the voltage to 378V, the pressure to 0.376Pa, and the reaction time to 300s, the Schottky contact of the Schottky diode pixel is obtained.

[0047] 6) Place the substrate on the coating machine and spin-coat the photoresist az1500 on the surface. Adjust the coating machine speed to 4000 rpm for 40 seconds. After the coating is completed, place the substrate on the drying table for drying. Adjust the drying table temperature to 90 degrees for 120 seconds. After drying, send the substrate to the UV lithography machine for photolithography. Adjust the exposure time of the lithography machine to 4 seconds, the waiting time to 30 seconds, and the spacing to 23. After the photolithography is completed, use the positive photoresist developer to develop the substrate for 14 seconds. The substrate needs to be shaken during the development process. After the development is completed, send the substrate to the magnetron sputtering. By adjusting the DC magnetron sputtering current to 0.4A, the voltage to 378V, the pressure to 0.376Pa, and the reaction time to 300s, the Crossbar multi-channel readout structure is connected to the Schottky diode pixel metal wire. At this time, the terahertz focal plane array detector chip is completed.

[0048] 7) The fabricated terahertz focal plane array detector chip is sent to the probe station for testing, the voltage is -1V to 1V, and the generated current-voltage characteristic curve is recorded to obtain Figure 8 From the pattern shown, it can be concluded that the terahertz focal plane array detector chip obtained by the process flow of the present invention has good performance, and the designed and manufactured Crossbar multi-channel readout architecture meets the needs of the terahertz focal plane array detector.

[0049] The technical features of the above embodiments may be arbitrarily combined. To make the description concise, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0050] The above-described embodiments only express several implementation methods of the present application, and the descriptions thereof are relatively specific and detailed, but they cannot be understood as limiting the scope of the present application. It should be pointed out that, for a person of ordinary skill in the art, several variations and improvements can be made without departing from the concept of the present application, and these all belong to the protection scope of the present application. Therefore, the protection scope of the present application shall be subject to the attached claims.

Claims

1. A terahertz focal plane array detector chip, characterized in that: It includes two parts: a Schottky diode pixel and a Crossbar multi-channel readout structure. The Schottky diode pixel includes two parts: an ohmic contact and a Schottky contact. The Crossbar multi-channel readout structure includes three parts: a horizontal electrode, a vertical electrode, and an isolation layer between the horizontal electrode and the vertical electrode. The horizontal electrode and the vertical electrode are arranged in a cross pattern. The isolation layer between the horizontal electrode and the vertical electrode is located between the horizontal electrode and the vertical electrode. The Schottky diode pixel and the Crossbar multi-channel readout structure are connected through metal wires.

2. The terahertz focal plane array detector chip according to claim 1, characterized in that: The transverse electrode is manufactured on the substrate by micro-nano processing technology, the isolation layer between the transverse electrode and the longitudinal electrode is manufactured on the transverse electrode by micro-nano processing technology, and the longitudinal electrode is manufactured on the isolation layer between the transverse electrode and the longitudinal electrode by micro-nano processing technology.

3. The terahertz focal plane array detector chip according to claim 1, characterized in that: The height of the horizontal electrode is h1=100nm, the height of the isolation layer between the horizontal electrode and the vertical electrode is h3=200nm, the height of the vertical electrode is h2>h1+h3, the height of the Crossbar multi-channel readout structure is h=h1+h2+h3, the width w of the horizontal electrode is equal to that of the vertical electrode, and h / w≤5 must be satisfied.

4. The terahertz focal plane array detector chip according to claim 3, characterized in that: The height of the vertical electrode h2 = 400nm, and the electrode width w = 10 microns.

5. The terahertz focal plane array detector chip according to claim 2, characterized in that: The substrate has a total of four layers, namely, substrate, buffer layer, epitaxial layer, and passivation layer. The bottom layer is the substrate, which is made of indium phosphide. Above the substrate is the buffer layer, which is made of highly doped gallium arsenide. Above the buffer layer is the epitaxial layer, which is made of low-doped gallium arsenide. Above the epitaxial layer is the passivation layer, which is made of silicon dioxide.

6. A method for preparing a terahertz focal plane array detector chip according to any one of claims 1 to 5, characterized in that: The steps include: The first step is to prepare the lateral electrodes in the Crossbar multi-channel readout structure: the lateral electrodes in the Crossbar multi-channel readout structure are obtained by sequentially performing spin coating of photoresist on the substrate, photolithography using an ultraviolet lithography machine, and magnetron sputtering growth of gold; The second step is to prepare an isolation layer between the horizontal electrode and the vertical electrode in the Crossbar multi-channel readout structure: the isolation layer between the horizontal electrode and the vertical electrode in the Crossbar multi-channel readout structure is obtained by sequentially performing spin coating of photoresist on the substrate, photolithography using an ultraviolet photolithography machine, and PECVD growth of a silicon nitride isolation layer; The third step is to prepare the vertical electrodes in the Crossbar multi-channel readout structure: the vertical electrodes in the Crossbar multi-channel readout structure are obtained by sequentially performing spin coating of photoresist on the substrate, photolithography using an ultraviolet lithography machine, and magnetron sputtering growth of gold; The fourth step is to prepare the ohmic contact of the Schottky diode pixel: the ohmic contact of the Schottky diode is obtained by sequentially performing spin coating of photoresist, photolithography with a UV lithography machine, RIE etching, and magnetron sputtering growth of gold on the substrate; The fifth step is to prepare the Schottky contact of the Schottky diode pixel: the Schottky contact of the Schottky diode is obtained by sequentially performing spin coating of photoresist, photolithography with a UV lithography machine, RIE etching, and magnetron sputtering growth of gold on the substrate; The sixth step is to prepare the metal wires connecting the Crossbar multi-channel readout structure with the Schottky diode pixels: by spin coating photoresist on the substrate, photolithography with a UV photolithography machine, and magnetron sputtering gold growth, the horizontal electrodes of the Crossbar multi-channel readout structure are connected to the ohmic contacts of the Schottky diode using metal wires, and the vertical electrodes of the Crossbar multi-channel readout structure are connected to the Schottky contacts of the Schottky diode using metal wires.

7. The method for preparing a terahertz focal plane array detector chip according to claim 6, characterized in that: The second step is to prepare an isolation layer between the horizontal electrode and the vertical electrode in the Crossbar multi-channel readout structure: the isolation layer between the horizontal electrode and the vertical electrode in the Crossbar multi-channel readout structure is obtained by sequentially performing spin coating of photoresist on the substrate, photolithography by an ultraviolet lithography machine, and PECVD growth of a silicon nitride isolation layer. The specific method is as follows: Spin-coat az1500 photoresist on the substrate surface, transfer the pattern of the isolation layer between the horizontal electrode and the vertical electrode to the photoresist by photolithography, develop the photoresist to obtain the pattern of the isolation layer between the horizontal electrode and the vertical electrode, and grow silicon nitride as the isolation layer between the horizontal electrode and the vertical electrode on the developed pattern of the isolation layer between the horizontal electrode and the vertical electrode by PECVD process, wherein: The PECVD temperature was adjusted to 150 degrees, the gas introduction rates were 80 sccm of silane, 40 sccm of nitrogen, and 120 sccm of nitrous oxide, the reaction power was 10 W, and the reaction time was 400 s.

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