CN103193190A - Infrared-terahertz dual-band array detector microbridge structure and preparation method thereof - Google Patents

Abstract

The present invention discloses a microbridge structure of an infrared-terahertz dual-band array detector and a preparation method thereof, which are used for detection and imaging in the infrared and terahertz bands. The top layer of the microbridge structure is a double-layer vanadium oxide film, and the lower vanadium oxide film is a non-phase-change vanadium oxide film with a high temperature coefficient of resistance (TCR), which is used as a sensitive layer in the infrared and terahertz bands. The upper vanadium oxide film has a lower phase transition temperature and can undergo a reversible phase transition from semiconductor phase to metal phase. When in the semiconductor phase, it is used together with the lower vanadium oxide film as an infrared absorption layer, and after the phase transition to the metal phase, it is used as a terahertz radiation absorption layer. The resonance of the microbridge structure can fully absorb infrared radiation, adjust the conductivity, refractive index and other photoelectric parameters of the metal phase vanadium oxide film, and maximize the absorption of terahertz radiation. The microbridge structure can realize dual-band detection and imaging, has a simple preparation process, is compatible with MEMS technology, and has broad application prospects.

Description

An infrared-terahertz dual-band array detector microbridge structure and its preparation method

technical field

The invention relates to the technical field of infrared and terahertz detection and imaging, in particular to a microbridge structure for an infrared-terahertz dual-band array detector and a preparation method thereof.

Background technique

As a supplement and extension to human senses, infrared detection technology has been widely used in civilian and military applications. At present, relatively mature photon detectors have been applied in communication, medicine, military and other fields, but because they must be refrigerated when they work, the whole system is huge, complex in structure and high in cost, which makes it impossible to promote and apply on a large scale. The development of large-scale integrated circuit technology has made it possible to develop uncooled infrared detectors. At present, the uncooled infrared focal plane array (IRFPA) technology has become the most mainstream direction of infrared detection technology. This technology enables us to obtain infrared detectors with high sensitivity at room temperature. In addition, its many advantages such as low cost, small size, light weight, low power consumption and wide response band make its large-scale marketization possible.

At present, the mainstream technology of uncooled infrared focal plane detector is thermistor microbolometer. To achieve infrared detection at room temperature, the design of the detection structure is the key to uncooled infrared focal plane devices. The microbridge structure is a typical detection structure. The supporting layer and the sensitive layer are patterned on the sacrificial layer by photolithography, and finally the sacrificial layer is removed, so that an independent thermal insulation micro-bridge structure can be formed. The micro-bridge is composed of bridge piers, bridge legs and bridge decks. It is fabricated on a substrate with a readout circuit. The bridge piers support the bridge legs and the bridge deck, so that the bridge legs and the bridge deck are suspended. The infrared absorption layer and the heat-sensitive film are deposited on the bridge deck. When the device is working, the lens made of germanium is used to collect and focus the infrared radiation to the sensitive element array located on the focal plane of the optical system. The change of the target infrared radiation is detected by the infrared detection film on the bridge surface and reflected to the heat sensitive film. Changes in temperature and resistance are transmitted to the substrate readout circuit through the electrical channel fabricated in the microbridge, and restored to image information to realize the detection of target signals. In order to make full use of the infrared radiation of the object, a reflective structure is usually added at the bottom of the sacrificial layer to improve the absorption of infrared radiation by the sensitive layer. It is generally considered that the microcavity formed when the distance between the sensitive layer and the reflective layer is 1/4 of the wavelength of the incident infrared light Absorbs best.

According to the different thermistor materials used, uncooled infrared focal plane detectors can be divided into vanadium oxide (VO _x ) detectors and amorphous silicon detectors. Vanadium oxide technology was successfully developed by Honeywell in the United States in the early 1990s. Currently, its patents are authorized by several companies such as BAE, L-3/IR, FLIR-INDIGO, DRS, NEC, and SCD. The amorphous silicon technology was mainly developed by the French CEA/LETI/LIR laboratory in the late 1990s, and is currently mainly produced by the French SOFRADIR and ULIS companies. Vanadium oxide is very sensitive to room temperature resistance temperature changes, and can obtain a large temperature coefficient of resistance (TCR, generally -2%/K~-3%/K), and the resistance value can be controlled from several thousand ohms to tens of thousands of ohms, 1 The /f noise is low, and the thin film deposition technology is mature, so it is the preferred thermistor material for uncooled infrared focal plane detectors. Companies such as Raytheon, BAE, DRS, Indigo, NEC, and SCD can produce vanadium oxide uncooled infrared focal plane detectors in 160×120~640×480 arrays, and their noise equivalent temperature difference (NETD) is 20~100mK. Currently, both BAE and DRS are researching large-scale vanadium oxide uncooled infrared focal plane detectors with a 1024×1024 array, a pixel size of 15 μm, and a NETD of 50 mK.

Terahertz (THz) waves refer to electromagnetic radiation with a frequency between 0.1-10THz (wavelength 3mm-30??m), and its electromagnetic spectrum lies between microwave and infrared bands. Therefore, terahertz systems take advantage of both electronics and optics. For a long time, due to the lack of effective terahertz radiation generation and detection methods, people's understanding of the properties of electromagnetic radiation in this band is very limited, so that this band is called the terahertz gap in the electromagnetic spectrum. This band is also the last frequency window in the electromagnetic spectrum to be fully studied. Compared with electromagnetic waves in other bands, terahertz electromagnetic waves have the following unique properties: ①Transient: the typical pulse width of terahertz pulses is on the order of picoseconds; ②broadband: terahertz pulse sources usually only contain several cycles Electromagnetic oscillation, the frequency band of a single pulse can cover the range from GHz to tens of THz; ③ coherence: the coherent measurement technology of terahertz time-domain spectroscopy technology can directly measure the amplitude and phase of the terahertz electric field, and can easily extract the refractive index of the sample , absorption coefficient; ④ low energy: the energy of terahertz photons is only millielectron volts, and will not destroy the detected substance due to ionization, so that biomedical detection and diagnosis can be safely performed; ⑤ Penetration: terahertz radiation is for Many non-polar insulating substances, such as cardboard, plastics, textiles and other packaging materials have high penetration characteristics, which can be used to detect hidden objects. These characteristics of terahertz waves make them have great scientific value and broad application prospects in object imaging, environmental monitoring, medical diagnosis, radio astronomy, broadband mobile communication, especially in satellite communication and military radar. In recent years, due to the development of free electron laser and ultrafast laser technology, a stable and reliable excitation light source has been provided for the generation of terahertz pulses, and the research on the generation mechanism, detection technology and application technology of terahertz radiation has been vigorously developed.

Terahertz detectors are key devices for the application of terahertz technology. In the development and application of terahertz detectors, detecting terahertz radiation signals is of great significance. The traditional uncooled infrared focal plane array structure can theoretically be used for detection and imaging in the terahertz band. According to the 1/4 wavelength theory, taking a radiation frequency of 3 THz as an example, in order to fully absorb terahertz radiation, the height of the optical resonator of the uncooled infrared focal plane array should be 25 μm (1/4 wavelength of the incident radiation). However, such a resonant cavity height is difficult to achieve in the preparation of devices (the resonant cavity height of traditional uncooled infrared focal plane arrays is about 1.5-3 μm). If the height of the resonant cavity is not changed, the absorption of terahertz radiation by its film structure is extremely low, making signal detection more difficult. In the literature (F. Simoens, etc, "Terahertz imaging with a quantum cascade laser and amorphous-silicon microbolometer array", Proceedings of SPIE, vol. 7485, pp. 74850M-1–74850M-9, 2009), based on non The uncooled infrared focal plane array of crystalline silicon is used for terahertz imaging. After simulation and experimental measurement, the terahertz radiation absorption rate of the detection unit is only 0.16~0.17%. Therefore, the commonly used solution at present is: keep the resonant cavity height of the uncooled infrared focal plane array unchanged, and add a special terahertz radiation absorbing layer on the top layer of the film structure to realize the detection and imaging of terahertz radiation . Alan W. M. Lee et al. reported real-time, continuous terahertz wave imaging using a 160×120 uncooled infrared focal plane array. The sensitive material is a vanadium oxide film on a silicon nitride microbridge. They proposed that in order to improve the signal-to-noise ratio and spatial resolution, the design of the focal plane array needs to be improved, and the main work is to optimize the terahertz radiation absorbing material (Alan W. M. Lee, etc, “Real-time, continuous-wave terahertz imaging by use of a microbolometer focal-plane array", Optics Letters, vol. 30, pp. 2563–2565, 2005).

Thin metal or metal composite films can absorb terahertz radiation, and the film thickness below 50nm has little effect on the heat capacity of the detector, which is conducive to the production of high response rate detection units, and is often used as the absorption of terahertz microarray detectors layer. N. Oda et al. used 320×240 and 640×480 uncooled infrared focal plane arrays based on vanadium oxide thermosensitive thin films to detect terahertz radiation. Because the absorption rate of the original film structure to terahertz radiation is only 2.6~4%. Therefore, they added a metal film with appropriate sheet resistance on the top layer of the film structure as a terahertz radiation absorbing layer, reducing the noise equivalent power to 40pW when the incident radiation frequency is 3THz (N. Oda, etc, " Detection of terahertz radiation from quantum cascade laser using vanadium oxide microbolometer focal plane arrays”, Proceedings of SPIE, vol. 6940, pp. 69402Y-1–69402Y-12, 2008). The use of metal thin films as terahertz radiation absorbing layers is also described in the literature (L. Marchese, etc, "A microbolometer-based THz imager", Proceedings of SPIE, vol. 7671, pp. 76710Z-1–76710Z-8, 2010) reported that terahertz radiation absorption can be maximized by optimizing the thickness of the metal absorbing layer.

In literature reports, after adding a metal thin film as a terahertz radiation absorbing layer, the uncooled infrared focal plane array can be used for detection and imaging in the terahertz band. However, in the detection unit, the dual-layer vanadium oxide film is used as the absorbing and sensitive layer in the infrared and terahertz bands at the same time, and the use of the reversible phase transition of the upper vanadium oxide film to achieve dual-band detection and imaging has not been reported, and there are no related invention patents. application.

Contents of the invention

The problem to be solved by the present invention is: how to provide a micro-bridge structure for an infrared-terahertz dual-band array detector, which can realize infrared-terahertz dual-band detection and imaging.

The technical problem proposed by the present invention is solved in this way: provide a kind of micro-bridge structure for infrared-terahertz dual-band array detector, it is characterized in that: comprise substrate 10, drive circuit 20, sacrificial layer 30, described The driving circuit is arranged on the substrate 10, and the driving circuit 20 is provided with a circuit interface 21; the sacrificial layer 30 is prepared on the substrate with the driving circuit, and a buffer layer 40 is sequentially prepared on the driving circuit from bottom to top , a support layer 50, and a top electrode 60, the top electrode is connected to the circuit interface; a lower vanadium oxide film and an upper vanadium oxide film are sequentially prepared on the top electrode and the support layer from bottom to top.

In the present invention, the vanadium oxide film in the lower layer is a non-phase-change vanadium oxide film with a high temperature coefficient of resistance, which is used as a sensitive layer in the infrared and terahertz bands,

In the present invention, the upper vanadium oxide film can undergo a reversible phase transition from semiconductor phase to metal phase, and when it is in the semiconductor phase, it can be used as an infrared absorption layer together with the lower vanadium oxide film; it can be used as a terahertz radiation absorption layer after it is a metal phase .

In the present invention, the phase transition temperature of the upper vanadium oxide film is 20-60°C, and the thickness is 5-100nm; the temperature coefficient of resistance of the lower vanadium oxide film is -2%/K~-6%/K, The thickness is 30~200nm.

In the present invention, after the sacrificial layer is released, a resonant cavity is formed at the position of the original sacrificial layer, and the height of the resonant cavity is 1.5-3 μm (about 1/4 of the wavelength of infrared radiation), so as to fully absorb target radiation in the infrared band.

In the present invention, the sacrificial layer material is one of polyimide, silicon dioxide, oxidized porous silicon and phosphosilicate glass.

The support layer is composed of a single-layer film or a multi-layer film, and the material is silicon dioxide or silicon nitride, and the thickness of the support layer is between 0.1 μm and 1 μm.

The material of the buffer layer is metal or metal alloy or non-metallic material; the material of the top electrode layer is aluminum, tungsten, titanium, platinum, nickel, chromium or any alloy thereof.

According to the preparation method of the microbridge structure provided by the present invention, it is characterized in that, comprising the following steps:

①Grow and pattern the sacrificial layer on the substrate with the driving circuit, so that the cross-sectional shape of the edge of the sacrificial layer pattern presents a positive trapezoidal shape, exposing the circuit interface of the driving circuit;

②Preparing a buffer layer pattern on a substrate with an existing sacrificial layer pattern;

③Preparing a support layer on the device obtained in step ②, and forming a support layer pattern with a photolithography process to expose the electrode interface;

④Preparing a top electrode layer on the device obtained in step ③, and forming a top electrode layer pattern with a photolithography process, requiring the top electrode layer to be electrically connected to the electrode interface;

⑤Preparing and patterning the lower vanadium oxide film used as the sensitive layer on the substrate on which the top electrode layer has been prepared;

⑥ Prepare and pattern the upper vanadium oxide film with low phase transition temperature;

⑦Release the sacrificial layer to form a micro-bridge structure, and then perform packaging to form a detection unit.

The lower vanadium oxide thin film used as the sensitive layer was prepared by magnetron sputtering; during sputtering, the sputtering power was controlled at 100-500W, the oxygen partial pressure was 0.5%-10%, the sputtering time was 5-60min, and the annealing temperature was 200~600℃.

The vanadium oxide film on the upper layer with a low phase transition temperature is prepared by magnetron sputtering; the doped elements are titanium, molybdenum, tungsten, etc., and the doping concentration is 0.1~10%; the sputtering power is controlled at 50~300W, The oxygen partial pressure is 0.5%~8%, the sputtering time is 2~30min, and the annealing temperature is 200~600°C.

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

The invention uses a double-layer vanadium oxide film as the absorbing and sensitive layer of infrared and terahertz wave bands simultaneously, uses the reversible phase transition of the upper vanadium oxide film to realize dual-band detection and imaging, and has a simple and reasonable preparation process.

Description of drawings

Among Fig. 1, a~h are the simple preparation process of the microbridge structure of the present invention, wherein Fig. 1-a is the substrate with bottom drive circuit, Fig. 1-b is the substrate prepared with sacrificial layer pattern, Fig. 1- c is the substrate with the buffer layer pattern prepared, Figure 1-d is the substrate with the support layer pattern prepared, Figure 1-e is the substrate with the top electrode layer pattern prepared, and 1-f is the lower vanadium oxide film prepared The substrate of the pattern, 1-g is the substrate on which the pattern of the upper vanadium oxide film is prepared, and 1-h is a schematic cross-sectional view of the device structure after releasing the sacrificial layer;

Fig. 2 is the variation curve of the resistance of lower layer vanadium oxide film with temperature in embodiment 2 of the present invention;

Fig. 3 is the variation curve of the resistance of upper layer vanadium oxide thin film with temperature in embodiment 2 of the present invention;

Reference numerals: 10 is a substrate, 20 is a driving circuit, 21 is a circuit interface, 30 is a sacrificial layer, 40 is a buffer layer, 50 is a support layer, 60 is a top electrode layer, 70 is a lower vanadium oxide film, 80 is an upper layer Vanadium oxide film.

Detailed ways

Below in conjunction with accompanying drawing and embodiment the present invention will be further described:

The present invention provides a microbridge structure for an infrared-terahertz dual-band array detector, which is characterized in that it includes a substrate 10, a driving circuit 20, and a sacrificial layer 30, and the driving circuit is arranged on the substrate 10. The drive circuit 20 is provided with a circuit interface 21; the sacrificial layer 30 is prepared on the substrate with the drive circuit, and a buffer layer 40, a support layer 50, and a top electrode 60 are sequentially prepared on the drive circuit from bottom to top. The top electrode is connected with the circuit interface; a lower vanadium oxide film and an upper vanadium oxide film are sequentially prepared on the top electrode and the support layer from bottom to top.

The preparation process of the micro-bridge structure of the present invention includes: preparing the sacrificial layer 30 on the substrate 10 with the driving circuit 20, and forming a sacrificial layer pattern by photolithography, and the formed sacrificial layer pattern will expose the bottom circuit Interface 21; prepare buffer layer 40 pattern; prepare support layer 50, and form support layer pattern by photolithography process, expose electrode interface 21; prepare top electrode layer 60, and form top metal electrode pattern by photolithography process, require top electrode and electrode interface 21 connected; prepare and pattern the lower vanadium oxide thin film 70 used as the sensitive layer; prepare and pattern the upper vanadium oxide thin film 80 used as the absorbing layer; after releasing the sacrificial layer, form infrared and terahertz radiation detection unit.

In the microbridge structure, the height of the resonant cavity is 1.5~3μm (about 1/4 of the infrared radiation wavelength) to fully absorb the target radiation in the infrared band; the material of the sacrificial layer is polyimide, silicon dioxide, oxidized porous Silicon, phosphosilicate glass, etc., the sacrificial layer can be removed by oxygen plasma bombardment, reactive ion etching or chemical reagents. The support material is required to have a certain rigidity to ensure the stability of the micro-bridge structure, and low stress to ensure that the micro-bridge is less deformed by heat. At the same time, try to choose a material with low thermal conductivity to prepare the bridge deck. The support layer is composed of a single-layer film. Or it is composed of multi-layer films, the material is silicon dioxide or silicon nitride, and the thickness of the support layer is between 0.1 and 1 μm. The purpose of setting the buffer layer is to weaken the height difference between the circuit interface and the top electrode layer, so as to facilitate the connection between the bottom circuit and the top metal wire, and the material of the buffer layer is metal or metal alloy or non-metallic material; the top electrode layer The material is aluminum, tungsten, titanium, platinum, nickel, chromium or any of their alloys.

The vanadium oxide film in the lower layer is a non-phase-change vanadium oxide film with a high temperature coefficient of resistance, which is used as a sensitive layer in infrared and terahertz bands, and is prepared by magnetron sputtering. During sputtering, the sputtering power is controlled to be 100~500W, the oxygen partial pressure is 0.5%~10%, the sputtering time is 5~60min, and the annealing temperature is 200~600°C. The temperature coefficient of resistance of the prepared vanadium oxide thin film is -2%/K~-6%/K, and the thickness is 30~200nm.

The upper vanadium oxide film has a low phase transition temperature, and can undergo a reversible phase transition from semiconductor phase to metal phase. When the semiconductor phase is used together with the lower vanadium oxide film, it is used as an infrared absorption layer, and it is used as a terahertz radiation absorption layer after the phase changes to a metal phase. . By stimulating the reversible phase transition of the vanadium oxide film on the upper layer by means of external heat, bias voltage, etc., and adjusting the photoelectric parameters such as the electrical conductivity and refractive index of the metal phase, the maximum absorption of terahertz radiation can be realized. The vanadium oxide film on the upper layer is prepared by magnetron sputtering. The low phase transition temperature is obtained by doping. The elements doped during preparation are titanium, molybdenum, tungsten, etc., and the doping concentration is 0.1-10%. The control sputtering power is 50~300W, the oxygen partial pressure is 0.5%~8%, the sputtering time is 2~30min, and the annealing temperature is 200~600℃. The phase transition temperature of the prepared vanadium oxide thin film is 20-60° C., and the thickness is 5-100 nm.

The present invention will be further described below by embodiment:

Example 1

A microbridge structure for infrared-terahertz dual-band array detectors, the preparation process of which is shown in Figure 1.

The micro-bridge structure is deployed on the substrate 10 on which the bottom driving circuit 20 has been prepared, and the driving circuit 20 has reserved a circuit interface 21, as shown in FIG. 1-a.

Clean the surface of the substrate to remove surface contamination, and bake the substrate at 200 ^o C to remove the moisture on the surface and enhance the bonding performance. Coating of photosensitive polyimide (sacrifice layer) with automatic glue coating track, adjusting the thickness of polyimide film by rotating speed, and baking the coated photosensitive polyimide at 120 ^o C to remove The solvent in some glues is beneficial to the neatness of the exposure lines. The photosensitive polyimide is exposed by a NIKON lithography machine, and the exposed substrate is sent to the automatic development track for developing the glue. The developing solution is the standard positive developing solution TMAH. The developed photosensitive polyimide pattern presents a pier hole pattern, as shown in Figure 1-b. Then place the polyimide film in an annealing oven protected by an inert gas for imidization treatment. The imidization temperature is set to rise in stages, the highest temperature is 250 ^o C ~ 400 ^o C, and the constant temperature time is 30 ~ 120min. The thickness of polyimide after imidization is in the range of 1.5-3 μm.

AZ5214 photoresist was used to prepare the metal aluminum buffer layer pattern. Firstly, the AZ5214 photoresist is spin-coated on the surface of the substrate, and then the mask exposure is performed. After the exposure is completed, it is baked with a hot plate (110 ^o C, 1.5min) to change the glue in the exposed part, and then the flood exposure process is carried out. Then develop to obtain the pattern that needs to be peeled off. The metal aluminum film is prepared by magnetron sputtering, and the thickness of the aluminum film is in the range of 0.3-1.5 μm. The photoresist was then stripped with acetone solution under ultrasonic conditions. After peeling off, the aluminum buffer layer pattern shown in Figure 1-c is left on one side.

A low-stress silicon nitride support layer is produced by using PECVD equipment and frequency mixing sputtering technology, and the thickness of the prepared silicon nitride layer is in the range of 0.2-1 μm. Then photolithography and etching are carried out on the thin film to etch out the pattern supporting the bridge deck. This layer of silicon nitride covers the pattern of the aluminum buffer layer at the piers, as shown in Figure 1-d.

AZ5214 photoresist was used to prepare the NiCr top electrode pattern. First, AZ5214 photoresist is spin-coated on the surface of the substrate after the substrate support layer is prepared, and then the mask exposure is performed. After the exposure is completed, it is baked with a hot plate (110 ^o C, 1.5min) to allow the glue on the exposed part to occur. Changes, followed by a pan exposure process, and then developed to obtain the pattern that needs to be peeled off. The NiCr thin film is prepared by magnetron sputtering, and the thickness of the NiCr thin film is in the range of 0.05-0.3 μm. The photoresist was then stripped with acetone solution under ultrasonic conditions. After peeling off, the NiCr electrode pattern shown in Figure 1-e is left on one side. The graph is interfaced with the underlying circuit.

After the electrode leads are prepared, the lower vanadium oxide thin film is prepared by sputtering equipment as a sensitive layer in the infrared and terahertz bands. During sputtering, the sputtering power is controlled to be 100~500W, the oxygen partial pressure is 0.5%~10%, the sputtering time is 5~60min, and the annealing temperature is 200~600°C. The temperature coefficient of resistance of the prepared vanadium oxide thin film is -2%/K~-6%/K, and the thickness is 30~200nm. Then photolithography and etching are performed on the vanadium oxide film to etch the pattern of the vanadium oxide film on the lower layer as shown in Fig. 1-f.

After the lower vanadium oxide film is prepared, the upper vanadium oxide film is prepared by sputtering equipment to be used as an absorbing layer in the infrared and terahertz bands. Low phase transition temperature is obtained by doping, the doped elements are titanium, molybdenum, tungsten, etc., and the doping concentration is 0.1~10%. The control sputtering power is 50~300W, the oxygen partial pressure is 0.5%~8%, the sputtering time is 2~30min, and the annealing temperature is 200~600℃. The phase transition temperature of the prepared vanadium oxide thin film is 20-60° C., and the thickness is 5-100 nm. Then photolithography and etching are performed on the vanadium oxide thin film, and the pattern of the upper vanadium oxide thin film as shown in Fig. 1-g is etched.

Oxygen plasma is used to bombard the device with double-layer vanadium oxide film pattern, and the imidized photosensitive polyimide (sacrificial layer) is removed to form an infrared and terahertz radiation detection unit with a silicon nitride bridge support structure , the cross-sectional schematic diagram of the detection unit is shown in Figure 1-h.

Example 2

Double-layer vanadium oxide film, in which the lower vanadium oxide film is a non-phase-change vanadium oxide film with a high temperature coefficient of resistance, which is used as a sensitive layer in the infrared and terahertz bands; the upper vanadium oxide film has a low phase transition temperature, and is used as an Absorbing layer in the terahertz band.

The lower vanadium oxide thin film is prepared by magnetron sputtering. During sputtering, the sputtering power was controlled to be 450W, the oxygen partial pressure was 7%, the sputtering time was 30min, the film thickness was about 70nm, and the annealing temperature was 350°C. The variation curve of the resistance of the prepared vanadium oxide film with temperature is shown in Figure 2, and the temperature coefficient of resistance of the film at 20-80 °C is –3%/K~-5%/K.

The upper vanadium oxide thin film was prepared by magnetron sputtering. The low phase transition temperature is obtained by doping, the doped element is tungsten, and the doping concentration is 4%. During sputtering, the sputtering power was controlled to be 150W, the oxygen partial pressure was 5%, the sputtering time was 15min, the film thickness was about 20nm, and the annealing temperature was 350°C. The variation curve of the resistance of the prepared vanadium oxide film with temperature is shown in Fig. 3, and the phase transition temperature of the film is 50°C.

Claims (10)

1. infrared-Terahertz two waveband detector array micro-bridge structure, it is characterized in that, comprise substrate (10), drive circuit (20), sacrifice layer (30), described drive circuit is arranged on the substrate (10), and this drive circuit (20) is provided with circuit interface (21); Described sacrifice layer (30) preparation has on the substrate of drive circuit at this, and from bottom to top preparing successively on drive circuit has cushion (40), supporting layer (50), top electrodes (60), and this top electrodes is connected with described circuit interface; On this top electrodes and supporting layer, from bottom to top prepare successively lower floor's vanadium oxide film and upper strata vanadium oxide film are arranged.

According to claim 1 infrared-Terahertz two waveband detector array micro-bridge structure, it is characterized in that described lower floor vanadium oxide film is the no phase transformation vanadium oxide film with high temperature coefficient of resistance, make infrared and sensitive layer terahertz wave band.

According to claim 1 infrared-Terahertz two waveband detector array micro-bridge structure, it is characterized in that, the reversible transition of semiconductor phase-metal phase can take place in described upper strata vanadium oxide film, for the semiconductor phase time is used as infrared absorption layer with lower floor's vanadium oxide film; For metal is made the terahertz emission absorbed layer after mutually.

According to claim 1 to 3 arbitrary described infrared-Terahertz two waveband detector array micro-bridge structure, it is characterized in that the phase transition temperature of described upper strata vanadium oxide film is 20 ~ 60 ℃, thickness is 5 ~ 100nm; The temperature-coefficient of electrical resistance Wei – 2%/K ~ – 6%/K of described lower floor vanadium oxide film, thickness is 30 ~ 200nm.

According to claim 1 infrared-Terahertz two waveband detector array micro-bridge structure, it is characterized in that after described sacrifice layer discharged, the position of former sacrifice layer formed resonator, this resonator height is 1.5 ~ 3 μ m; Described sacrificial layer material is a kind of in the porous silicon of polyimides, silica, oxidation and the phosphorosilicate glass.

According to claim 1 infrared-Terahertz two waveband detector array micro-bridge structure, it is characterized in that, described supporting layer is made of single thin film or is made of plural layers, and material is silica or silicon nitride, and the thickness of supporting layer is between 0.1 ~ 1 μ m.

According to claim 1 infrared-Terahertz two waveband detector array micro-bridge structure, it is characterized in that described cushioning layer material is metal or metal alloy or nonmetallic materials; Described top electrodes layer material is aluminium, tungsten, titanium, platinum, nickel, chromium or any their alloy.

According to claim 1 infrared-preparation method of Terahertz two waveband detector array micro-bridge structure, it is characterized in that, may further comprise the steps:

1. at the substrate growth sacrifice layer that has drive circuit and graphical, make the section configuration of sacrifice layer pattern edge present the trapezoid shape, expose the circuit interface of drive circuit;

2. the substrate at existing sacrifice layer pattern prepares the cushion pattern;

3. step 2. the device of gained prepare supporting layer, and form the supporting layer pattern with photoetching process, expose electrode interface;

4. step 3. the device of gained prepare top electrode layer, and form the top electrodes layer pattern with photoetching process, require top electrode layer to be electrically connected with electrode interface;

5. in the substrate preparation for preparing top electrode layer as lower floor's vanadium oxide film of sensitive layer and it is graphical;

6. preparation has the upper strata vanadium oxide film of low transformation temperature and it is graphical;

7. releasing sacrificial layer forms micro-bridge structure, encapsulates the formation probe unit then.

According to claim 8 infrared-preparation method of Terahertz two waveband detector array micro-bridge structure, it is characterized in that, adopt the magnetron sputtering method preparation as lower floor's vanadium oxide film of sensitive layer; The control sputtering power is 100 ~ 500W during sputter, and partial pressure of oxygen is 0.5% ~ 10%, and sputtering time is 5 ~ 60min, and annealing temperature is 200 ~ 600 ℃.

According to claim 8 infrared-preparation method of Terahertz two waveband detector array micro-bridge structure, it is characterized in that the upper strata vanadium oxide film with low transformation temperature adopts the magnetron sputtering method preparation; Doping elements is titanium, molybdenum, tungsten etc. during preparation, and doping content is 0.1 ~ 10%; The control sputtering power is 50 ~ 300W, and partial pressure of oxygen is 0.5% ~ 8%, and sputtering time is 2 ~ 30min, and annealing temperature is 200 ~ 600 ℃.

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