WO2013170455A1 - 像素化闪烁晶体薄膜及其制备和应用 - Google Patents

像素化闪烁晶体薄膜及其制备和应用 Download PDF

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Publication number
WO2013170455A1
WO2013170455A1 PCT/CN2012/075570 CN2012075570W WO2013170455A1 WO 2013170455 A1 WO2013170455 A1 WO 2013170455A1 CN 2012075570 W CN2012075570 W CN 2012075570W WO 2013170455 A1 WO2013170455 A1 WO 2013170455A1
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Prior art keywords
scintillation crystal
pixelated
scintillation
substrate
crystal film
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PCT/CN2012/075570
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English (en)
French (fr)
Inventor
李秋莹
于波
于洪波
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吉林省锐意美科技有限公司
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Priority to EP12876785.2A priority Critical patent/EP2851708B1/en
Priority to CN201280035759.2A priority patent/CN103917895B/zh
Priority to PCT/CN2012/075570 priority patent/WO2013170455A1/zh
Publication of WO2013170455A1 publication Critical patent/WO2013170455A1/zh

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    • GPHYSICS
    • G01MEASURING; TESTING
    • G01TMEASUREMENT OF NUCLEAR OR X-RADIATION
    • G01T1/00Measuring X-radiation, gamma radiation, corpuscular radiation, or cosmic radiation
    • G01T1/16Measuring radiation intensity
    • G01T1/20Measuring radiation intensity with scintillation detectors
    • G01T1/202Measuring radiation intensity with scintillation detectors the detector being a crystal
    • GPHYSICS
    • G21NUCLEAR PHYSICS; NUCLEAR ENGINEERING
    • G21KTECHNIQUES FOR HANDLING PARTICLES OR IONISING RADIATION NOT OTHERWISE PROVIDED FOR; IRRADIATION DEVICES; GAMMA RAY OR X-RAY MICROSCOPES
    • G21K4/00Conversion screens for the conversion of the spatial distribution of X-rays or particle radiation into visible images, e.g. fluoroscopic screens

Definitions

  • a scintillation material is a material that converts electromagnetic waves (such as ultraviolet light, gamma rays, or X-rays, etc.) that are invisible to the naked eye into visible light.
  • electromagnetic waves such as ultraviolet light, gamma rays, or X-rays, etc.
  • detection and imaging technologies based on scintillation materials are widely used in nuclear medicine, safety inspection, industrial non-destructive testing, high-energy physics and space physics.
  • the visible light generated by the scintillation material after absorbing electromagnetic waves is divergent, which seriously reduces the spatial resolution during imaging.
  • the vacuum light deposition technology is used to control the process conditions to form a scintillation material into a micro-column structure of a scintillation crystal film (Detector utilizing a scintillator and photoconductive material, US Patent 3,275,827, 1965), which will produce visible light. Limited to microcolumnar crystals to reduce light divergence. However, since the microcolumns adhere to each other, they are limited in high-resolution detection.
  • the scintillation material is often made into a pixelated film, and is coupled with a charge coupled device (CCD) sensor, a photodiode-thin film transistor detection array, and a complementary metal oxide semiconductor.
  • CCD charge coupled device
  • CMOS complementary Metal-Oxide-Semiconductor
  • Scheme 1 Island-like structure When the thickness of the scintillation crystal film increases, the scintillation crystals on the island and the island will adhere to each other, causing the separated islands to disappear, eventually forming a continuous film and reducing the spatial resolution.
  • Scheme 2 Laser ablation The equipment is expensive, the process is complicated, and the yield is low;
  • Solution 3 The substrate material is strictly required, and the microporous structure process is complicated, and the scintillation material is not easy to completely fill the inside of the micropore.
  • the inventors conducted intensive studies, and surprisingly found that the surface induced self-isolation method of the present invention can effectively weaken and block the visible light generated by the scintillation crystal in the pixel unit from reaching the adjacent pixel unit. And the method is simple, no expensive laser ablation equipment is needed.
  • a first aspect of the invention provides a pixelated free-standing crystal film comprising:
  • a surface pixelized substrate wherein the surface of the surface pixelized substrate is composed of a pixel unit region separated from each other and an isolation band region between the pixel unit regions, and the isolation band region between each two adjacent pixel unit regions is independent
  • the ground includes n isolation bands, where n is an integer greater than or equal to 1, and the number n of isolation strips in the isolation zone at different positions may be the same or different;
  • the scintillation crystal on the pixel unit region has a first topography
  • the scintillation crystal on the isolation strip has a second topography to an (n+1)th topography
  • the first shape is different from the second topography to the (n+1)th topography
  • the second topography to the (n+1)th topography may be identical to each other or may be different 'where n is as defined above.
  • a second aspect of the present invention provides a method of fabricating a pixelated scintillation crystal film, which comprises: (1) providing a surface pixelized substrate composed of a pixel unit region and an isolation band region, wherein a surface of the pixel unit region Suitable for growing crystals having a first topography, isolation regions between adjacent pixel unit regions
  • the buffer zone comprising n lines, where n is an integer greater than 1, the surface topography of the isolation zone suitable for the growth of the crystal morphology of the first, the number n of spacer strip tape isolated area may be the same of different positions Or different
  • a third aspect of the invention provides the use of the above-described pixelated scintillation crystal film for ultraviolet detection, gamma ray detection and X-ray detection.
  • the surface-induced self-isolated pixelated scintillation crystal film provided by the invention can effectively improve the spatial resolution of the film during imaging, has a simple preparation process, and is easy to integrate with the existing photodetection system to realize digital detection.
  • FIG. 1 is a schematic illustration of the surface of a surface pixelated substrate.
  • Figure 2 is an enlarged schematic view of a partial surface of Figure 1.
  • Figure 3 is a schematic cross-sectional view of a surface-induced self-isolated pixelated scintillation crystal film.
  • Figure 4 is a schematic illustration of a process for preparing a pixelated scintillation crystal film in accordance with an embodiment of the present invention.
  • Figure 5 is a schematic illustration of a process for preparing a pixelated scintillation crystal film in accordance with another embodiment of the present invention.
  • Figure 6 is a schematic illustration of a process for preparing a pixelated scintillation crystal film in accordance with yet another embodiment of the present invention.
  • Figure 7 is a schematic illustration of a process for preparing a pixelated scintillation crystal film in accordance with yet another embodiment of the present invention.
  • Fig. 8 is a transmission optical micrograph of the yttrium iodide (ytterbium iodide) crystal film of Example 1 in the case of normal incident light.
  • Figure 9 is a transmission optical microscope image of the tilting 45 degree angle of the corresponding film of Figure 8.
  • Figure 10 is a cross-sectional scanning electron micrograph of the corresponding film of Figure 8.
  • Figure 11 is a transmission optical micrograph of a crystalline ruthenium (ruthenium iodide) crystal film prepared according to the method described in Example 1, wherein the surface of the pixel unit region is glass, and the surface of the separator is polyvinyl alcohol (PVA;).
  • Figure 12 is a cross-sectional scanning electron micrograph of the corresponding film of Figure 11.
  • Figure 13 is a transmission spectrum of a 30 ⁇ m thick CsI:TlI (10000:8) film deposited on the surface of glass and polyvinyl alcohol under the same conditions as described in Example 1.
  • Figure 14 is an X-ray diffraction diagram of the two films corresponding to Figure 13.
  • Figure 15 is a cross-sectional scanning electron micrograph of the scintillation crystal film prepared in Example 7.
  • Figure 16 is a transmission optical micrograph of a scintillation crystal film prepared in Example 13.
  • Figure 17 is a transmission optical micrograph of the scintillation crystal film prepared in Example 19.
  • pixelation in the present invention refers to a pixel unit in which scintillation materials are prepared to be separated from each other, and visible light generated by the scintillation material in the pixel unit does not interfere with adjacent pixel units, thereby realizing a space for germanium. Resolution.
  • scintillation crystal refers to a crystal formed of a scintillating material
  • pixel unit region refers to a region in which a scintillation crystal grown as a pixel unit
  • pixel unit refers to a scintillation crystal film at At the time of imaging, the smallest complete flaw of the resulting image corresponds to the scintillation crystal
  • isolated band refers to the area between the pixel unit regions, and there is at least one isolation in the isolation zone between adjacent pixel unit regions.
  • spacer refers to a region in which the surface properties of the isolation zone are different from those of the pixel cell region; the term “surface induction” means that the scintillation crystals that are grown thereon are different due to the different surface properties of the material. Morphology.
  • different topography means that the crystals forming the film exhibit differences in the morphology of the film due to differences in crystal structure, geometry or stacking pattern, and may be expressed as, but not limited to, at least one of the following -
  • a first aspect of the invention provides a pixelated scintillation crystal film, comprising: a surface pixelized substrate, the surface of the surface pixelized substrate being composed of pixel unit regions separated from each other and an isolation band region between the pixel units And a scintillation crystal on the surface pixelized substrate; wherein the scintillation crystal on the pixel unit region has a first topography, and at least one isolation strip is present in the isolation strip region, on the isolation strip The scintillation crystal has a different morphology than the first topography.
  • One or more spacer strips may be included in the spacer between each two adjacent pixel units, and the length and/or width of the spacer strips may be the same or different. The spacers located at different locations may have the same or different number of space
  • the pixelated scintillation crystal film of the present invention comprises:
  • a surface pixelized substrate wherein the surface of the surface pixelized substrate is composed of a pixel unit region separated from each other and an isolation band region between the pixel unit regions, and the isolation band region between each two adjacent pixel unit regions is independent
  • the ground includes n isolation bands, where n is an integer greater than or equal to 1, and the number n of isolation strips in each isolation zone may be the same or different;
  • the scintillation crystal on the pixel unit region has a first topography
  • the scintillation crystal on the isolation strip has a second topography to an (n+1)th topography
  • the first shape is different from the second topography to the (n+1)th topography
  • the second topography to the (n+1)th topography may be the same or different from each other, wherein n is as defined above.
  • the material of the substrate in the present invention is not particularly limited.
  • substrate materials that can be used as the substrate of the present invention include, but are not limited to, glass, ceramics, metals, metal oxides, polymers, silicon dioxide, graphite, silicon nitride, charge coupled device sensors, photodiode-thin film transistor detection arrays, and complementary Metal oxide semiconductor image sensor.
  • the present invention has no particular requirement for the transparency of the substrate, but it is preferable to use a transparent substrate.
  • the surface properties of the pixel unit region and the isolation strip region are different, such that under the same conditions, the scintillating material grows on the above two surfaces to obtain crystals having different morphologies, wherein the pixel unit region
  • the visible light transmittance of the formed crystal having the first topography is higher than the visible light transmittance of the crystal having the second topography to the (n+1)th topography formed on the spacer.
  • the surface properties of both the pixel unit and the spacer are such that the transmittance of the crystal having the first topography formed on the pixel unit is greater than the transmittance of the crystal formed on the spacer Appearance to the topography Measuring the transmittance of the crystal under the same conditions is at least 1%, preferably at least 1.5%, more preferably at least 2% higher, further preferably at least 2.5% higher, most preferably at least 3% higher, according to the transmittance of the absolute differences Value meter.
  • the transmittance of the crystal on the pixel unit is at least higher than the transmittance of the crystal on the spacer for the transmittance of visible light having a wavelength of 550 am. 1%, preferably at least 1.5°/. More preferably, it is at least 2% higher, more preferably at least 2.5% higher, and most preferably at least 3% higher.
  • the geometry of the pixel unit area is not particularly limited and can be designed according to specific application requirements. For example, according to certain preferred embodiments, any one or more of a rectangle, a square, a triangle, or a hexagon may be used.
  • the pixel cell geometry can also have rounded corners (ie, not right angles), such as rectangles with rounded corners, squares, triangles, hexagons, etc., and may even be stadium-shaped (ie, the sides are semi-circular and rectangular).
  • the length of any side of the geometry of the pixel unit is no less than 10 microns, no more than 500 microns, more preferably 15 to 300 microns, still more preferably 20-250 microns, most preferably It is 25-150 microns.
  • the width of the isolation strip and the width of the spacer in the spacer region are not particularly limited as long as the visible light generated by the scintillation material in the adjacent pixel unit can be effectively isolated.
  • the width of the isolation strip between adjacent pixel units is no less than 1 micron, no more than 50 microns, more preferably 2-40 microns, further preferably 3-30 microns, and most preferably 4-20.
  • the width of the spacer in the spacer region is not less than 1 ⁇ m, not more than 50 ⁇ m, more preferably 2 to 40 ⁇ m, further preferably 3 to 30 ⁇ m, and most preferably 4 to 20 ⁇ m.
  • the spacers at different positions may have the same or different widths and are not particularly limited. However, from the viewpoint of ease of handling, it is preferred that the spacers at different positions have substantially the same width. There is no particular limitation on the number of the separators in the present invention.
  • More than one spacer can be placed in all or part of the isolation zone.
  • the geometry of the spacer is not particularly limited, but it must be ensured that each pixel unit region is separately located inside the smallest closed geometry surrounded by the spacer, and the "minimum closed geometry" does not exist inside the spacer.
  • the kind of the pixel unit region surface material and the spacer surface material but their surface materials should be such that the morphology of the scintillation crystal formed on the pixel unit region is different from that in the isolation. The morphology of the scintillation crystal formed on the belt.
  • the pixel cell region surface can be any material that has good wettability with the scintillating material.
  • the surface of the separator may be any material which has poor wettability with the scintillation material.
  • the surface of the separator may be a polymer material having a hydroxyl group or a carboxyl group in the side chain, or the surface of the separator may be formed by a chemical reaction or the like.
  • the polymer material of the original side chain without a mercapto group or a hydroxyl group is partially or completely converted into a polymer material having a hydroxyl group or a carboxyl group in the side chain.
  • the material for forming the scintillation crystal is not particularly limited in the present invention. Examples of such materials include, but are not limited to, cesium iodide, sodium iodide, cesium bromide, lithium iodide, strontium ruthenate or a mixture of several, preferably cesium iodide, sodium iodide and strontium ruthenate. Any one or a mixture of several, more preferably a mixture of either or both of cesium iodide and sodium pentoxide.
  • the scintillation crystal may contain a dopant material.
  • doped materials include, but are not limited to, one or a mixture of cesium iodide, cesium bromide, sodium iodide, cesium iodide.
  • the combination of scintillation crystal material-tacky material may be cesium iodide-sodium iodide, cesium iodide- cesium iodide, sodium iodide- cesium iodide, strontium bromide-bromide bromide And lithium iodide - cesium iodide.
  • a plurality of scintillation crystal materials and/or a plurality of dopant materials may be simultaneously employed in the combination of the smectic crystal material-doped material.
  • the molar ratio of the scintillation crystal material to the miscellaneous material is not particularly limited and may be determined according to the luminous efficiency of the scintillation crystal to be achieved.
  • the molar ratio of the scintillation crystal material to the modified material is not less than 100:1, not more than 10,000:1, and the molar ratio is more preferably (150-8000):1, further preferably (200- 5000): 1, most preferably C 1000-2000): 1 .
  • the reflective material can be covered and filled on the side of the substrate where the scintillation crystal is not grown or the surface of the scintillation crystal and the gap. Or the refractive index is less than the flash used The substance of the crystal.
  • at least one layer of the reflective material may be covered on the side of the substrate where the scintillation crystal is not grown or the surface of the pixelated scintillation crystal film, and the gap in the film may be partially or completely filled with the reflective material.
  • Reflective materials are used to reduce the loss of visible light generated by scintillation crystals. Examples of reflective materials that can be used in the present invention include, but are not limited to, metallic aluminum and metallic silver.
  • the thickness of the reflective material film is not particularly limited and may be determined according to the reflective effect desired, for example, may be greater than
  • the thickness of the reflective material film is no greater than 1000 nanometers.
  • at least one layer of low refractive index material may be covered on the side of the substrate where the scintillation crystal is not grown or the surface of the pixelated scintillation crystal film, and the gap in the film may be partially or completely filled with the low refractive index material.
  • the low refractive index material is used to reduce the loss of visible light generated by the excitation of the scintillation crystal, which has a refractive index less than the refractive index of the scintillation crystal used.
  • low refractive index materials examples include, but are not limited to, titanium dioxide and silicon dioxide.
  • the thickness of the film of the low refractive index material is not particularly limited and may be determined depending on the effect desired, and may be, for example, greater than 50 nm, preferably greater than 100 nm, and more preferably greater than 200 nm.
  • the low refractive index material film has a thickness of no greater than 1000 nanometers.
  • at least one layer of reflective material and at least one layer of low refractive index material may be separately coated on the surface of the pixelated scintillation crystal film, or at least one layer of a combination of a reflective material and a low refractive index material may be covered.
  • 1 is a schematic view of a surface of a surface pixelized substrate, wherein 1 is a surface pixelated substrate whose surface is composed of a pixel cell region 2 and an isolation band region 3 between the pixel cell regions.
  • 2 is a partial enlarged view of a surface pixilated substrate in which at least one isolation strip 4 is present in the isolation strip region 3, and the surface properties of the spacer strip are different from those of the pixel unit region.
  • FIG. 3 is a schematic cross-sectional view of a surface-induced self-isolated pixelated scintillation crystal film, wherein 1 is a surface pixelated substrate, and 5 and 6 are scintillation crystals grown on the surface of the pixel unit and the isolation strip, respectively, in accordance with some embodiments of the present invention.
  • the surface induction refers to the fact that the surface properties of the pixel unit region 2 and the isolation strip 5 on the surface pixelized substrate 1 are different, and the growth of the scintillating material on the surface of the pixel unit region 2 is induced.
  • the scintillation crystal 5 and the scintillation crystal 6 obtained on the surface of the spacer 4 are different in morphology.
  • the surface of the pixel unit region 2 and the scintillation material have good wettability, and the contact angle between the two is less than 90 degrees, and the scintillation material is easy to grow to form an upright columnar crystal; the surface of the spacer 4 and the scintillation material are not wet, between the two The contact angle is greater than 90 degrees, and the scintillating material is not easily grown to form an upright columnar crystal.
  • the self-isolation means that the scintillation crystal prepared on the surface pixelized substrate 1 can simultaneously grow crystals of two different morphologies under the induction of the surface of the substrate, and the preparation process is simple.
  • the scintillation crystal 6 grown on the spacer 4 has a significant optical isolation effect and a spatial size as small as nanometers, achieving an effect of improving the spatial resolution of the film.
  • the sensitivity of the film imaging can be improved by using the optical signal generated by the isolation strip.
  • the scintillation crystal 5 on the pixel unit area 2 is different from the scintillation crystal 6 on the isolation strip 4 (for example, in some aspects, the former is an upright columnar structure, and the latter is a tilted or curved columnar structure)
  • the former is an upright columnar structure, and the latter is a tilted or curved columnar structure
  • the latter is a tilted or curved columnar structure
  • cracks are generated near the interface of the two types of structures, forming a flicker crystal air-sparkle crystal interface.
  • the refractive index of the scintillation crystal is larger than the refractive index of the air, the scintillation crystals on the pixel unit and the isolation band are generated. The visible light reaches the scintillation crystal - the air interface is totally reflected, and the light is reflected back into the interior of the two to achieve optical isolation.
  • the scintillation crystal 6 grown on the spacer 4 has a tilted or curved structure, which can function like an optical lens, can change the direction of light propagation, and has a wide angular range from neighboring pixel units.
  • the internal light has a capturing effect, and the optical interference effect of the neighboring pixel unit is isolated.
  • the scintillation crystal 6 grown on the spacer 4 has a tilted or curved structure and can function as an optical fiber to transmit the light generated by the scintillation crystal grown on the spacer to
  • the isolation band and the adjacent pixel unit can fully utilize the light signal generated by the scintillation crystal grown on the isolation band to achieve the effect of improving sensitivity.
  • a second aspect of the present invention provides a method of fabricating a pixelated scintillation crystal film, which comprises: (1) providing a surface pixelized substrate composed of a pixel unit region and an isolation band region, wherein the pixel sheet The surface of the meta-region is suitable for growing crystals having a first topography, and the isolation strip region between adjacent pixel unit regions includes n isolation strips, wherein n is an integer greater than or equal to 1, and the surface of the isolation strip is suitable for growth a crystal having a different appearance from the first topography, and the number n of the spacer strips in the isolation zone at different positions may be the same or different;
  • a scintillation crystal formed of a scintillating material and an optional dopant material is grown on the surface pixelized substrate to form a pixelated scintillation crystal film.
  • Scheme 2 the geometry and size of the spacers used in Figure 5 are identical to the geometry and size of the spacer strips,
  • the method for preparing the pixelated scintillation crystal film of the present invention comprises the following steps:
  • the surface of the substrate formed in (1) is covered with at least one surface material 7 capable of lifting or reducing the wettability of the substrate surface and the scintillating material;
  • a scintillation crystal formed of a scintillation material and an optional doping material is grown on the surface pixelized substrate to form a pixelated scintillation crystal film.
  • the geometry and size of the spacers used in Figure 6 are identical to the geometry and size of the spacer strips for ease of understanding, but are implemented
  • the method for preparing the pixelated scintillation crystal film of the present invention comprises the following steps:
  • a scintillation crystal formed of a scintillation material and an optional dopant material is grown on the surface pixelized substrate to form a pixelated scintillation crystal film.
  • Scheme 4 the geometry and size of the spacers used in Figure 7 are identical to the geometry and size of the spacer strips for ease of understanding, but are implemented
  • the method for preparing the pixelated scintillation crystal film of the present invention comprises the following steps:
  • a scintillation crystal formed of a scintillation material and an optional doping material is grown on the surface pixelized substrate to form a pixelated scintillation crystal film.
  • the present invention is not particularly limited to the technique of growing a crystal of a scintillator material formed of a scintillation material and an optional rubbing material on a surface pixelized substrate.
  • a scintillation material and an optional dopant material can be deposited on the surface pixelated substrate using vacuum co-deposition techniques to form a pixelated scintillation crystal film.
  • the reflective material or the substance having a refractive index smaller than that of the scintillation crystal used may be covered and filled on the side of the substrate where the scintillation crystal is not grown or the surface of the scintillation crystal and the gap.
  • at least one layer of the reflective material may be covered on the side of the substrate where the scintillation crystal is not grown or the surface of the pixelated scintillation crystal film, and the gap in the film may be partially or completely filled with the reflective material, Reflective materials are used to reduce the loss of visible light generated by scintillation crystals.
  • Examples of reflective materials that can be used in the present invention include, but are not limited to, metallic aluminum and metallic silver.
  • the thickness of the reflective material film is not particularly limited and may be determined depending on the desired retroreflective effect, for example, may be greater than 50 nm, preferably greater than 100 nm, and more preferably greater than 200 nm. Preferably, the thickness of the reflective material film is no greater than 1000 nanometers.
  • at least one layer of low refractive index material may be covered on the side of the substrate where the scintillation crystal is not grown or the surface of the pixelated scintillation crystal film, and the gap in the film may be partially or completely filled with the low refractive index material.
  • the low refractive index material is used to reduce the loss of visible light generated by the excitation of the scintillation crystal, which has a refractive index less than the refractive index of the scintillation crystal used.
  • low refractive index materials that can be used in the present invention include, but are not limited to, titanium dioxide and silicon dioxide.
  • the thickness of the low refractive index material film is not particularly limited and may be determined according to the effect desired, and may be, for example, greater than 50 nm, preferably greater than 100 nm, and more preferably greater than 200 nm.
  • the low refractive index material film has a thickness of no greater than 1000 nanometers.
  • At least one layer of reflective material and at least one layer of low refractive index material may be separately coated on the surface of the pixelated scintillation crystal film, or at least one layer of a combination of a reflective material and a low refractive index material may be covered.
  • a third aspect of the invention provides the use of the above-described pixelated scintillation crystal film for ultraviolet detection, X-ray detection and gamma ray detection.
  • the surface-induced self-isolated pixelated scintillation crystal film of the present invention can be combined with existing photodetection systems, such as charge coupled device sensors (CCD sensors), photodiode-thin film transistor detection arrays, and complementary metal oxide semiconductor image sensors (CMOS image sensors).
  • CCD sensors charge coupled device sensors
  • CMOS image sensors complementary metal oxide semiconductor image sensors
  • the pixelated scintillation crystal film of the present invention can convert X-rays into visible light and integrate with a charge coupled device sensor, a photodiode-thin film transistor detection array, or a complementary metal oxide semiconductor image sensor for digitization. Detection. According to certain embodiments, the pixelated scintillation crystal film of the present invention can convert ultraviolet light into visible light, and with a charge coupled device sensor, a photodiode-thin film transistor detection array, or a complementary metal The oxide semiconductor image sensor is integrated to realize digital detection.
  • the pixelated scintillation crystal film of the present invention can convert gamma rays into visible light and integrate with a charge coupled device sensor, a photodiode-thin film transistor detection array, or a complementary metal oxide semiconductor image sensor. Digital detection.
  • the pixelated scintillation crystal film obtained by the surface induced self-isolation method of the invention can effectively improve the spatial resolution of the film during imaging, has a simple preparation process, and is easy to integrate with the existing photodetection system to realize digital detection.
  • EXAMPLES The reagents, specifications and sources used in the present invention are listed in Table 1 in Table 1.
  • a scintillation crystal pixelated film was prepared by the method of preparing a scintillation crystallized film by surface induced self-isolation technique provided in the scheme 1 described above, and the specific process is as follows -
  • the above prepared solution is coated on the surface of the silicon nitride substrate, and the conditions are as follows: spin coating technique, 3000 rpm, time 30 seconds;
  • Csl cesium iodide
  • T1I cesium iodide
  • Figure 8 is a transmission optical micrograph (parallel light vertical film incidence) of a CsI:TlI (10000:8) film grown on the surface of a silicon chloride substrate according to Example 1.
  • the surface of the pixel unit area is silicon nitride
  • the surface of the isolation strip is PVA
  • the isolation strip has a width of 10 ⁇ m
  • 2 is a scintillation crystal grown on the surface of the pixel unit region, and has good optical transparency
  • 3 is a flicker growing on the surface of the isolation strip. Crystals, with poor optical transmission, can provide significant optical isolation.
  • Figure 9 is a transmission optical micrograph of the corresponding film of Figure 8, with parallel light at an angle of 45 to the film.
  • 2 is a scintillation crystal grown on the surface of the pixel unit region, and has good optical transparency.
  • 3 is a scintillation crystal grown on the surface of the spacer, and has poor optical transparency, which can provide a significant optical isolation effect.
  • FIG. 8 the spatial resolution of the film was calculated to be 5.5 line pairs/mm, which was greatly improved in spatial resolution compared with the existing 3.5 line pair/mm scintillation crystal film.
  • Figure 10 is a cross-sectional scanning electron micrograph of the corresponding film of Figure 8. 2 is the scintillation crystal grown on the surface of the pixel unit area, and 3 is the scintillation crystal grown on the surface of the isolation strip. There is a significant difference between the two crystal morphology. At the interface between the two crystals, the internal stress of the two crystals can be observed. Different cracks.
  • Figure 11 is a transmission optical micrograph of a CsI:TlI (l 0000:8) film grown on the surface of a glass substrate according to the method described in Scheme 1.
  • the surface of the pixel unit area is glass, the surface of the isolation strip is PVA, and the width of the isolation strip is 50 and 35 micrometers respectively;
  • 2 is a scintillation crystal grown on the surface of the pixel unit area, and the optical transparency is good, 3 is growing on the surface of the isolation strip.
  • the scintillation crystal has poor optical transmission.
  • Figure 12 is a cross-sectional scanning electron micrograph of the corresponding film of Figure 11.
  • 2 is the scintillation crystal grown on the surface of the pixel unit area
  • 3 is the scintillation crystal grown on the surface of the isolation strip.
  • Figure 13 is a transmission spectrum diagram of vacuum deposition of 30 ⁇ m thick CsI:TI (l 0000:8) on glass and PVA surfaces under the same conditions. It can be seen from the figure that under the same conditions, the transmittance of the two different morphological scintillation crystal films grown on the two surfaces is different.
  • the two kinds of scintillation crystal films having a thickness of 30 ⁇ have a difference in transmittance of visible light having a wavelength in the range of 400 to 800 nm of not less than 1%.
  • the difference in visible light transmission is as high as about 4%.
  • Fig. 14 is an X-ray diffraction diagram of the two films corresponding to Fig. 13, and it is seen that there are four distinct diffraction peaks in the scintillation crystal film grown on the surface of the PVA, and three distinct flicker crystal films grown on the surface of the glass.
  • the diffraction peak At the same time, the intensity of the diffraction peak at the same position in the two films is also different.
  • the presence of the derivative peak indicates that the scintillation material forms a crystal in the film, and the difference in the position and intensity of the diffraction peak indicates that the crystal composition and the stacking mode are different in the two films.
  • Table 3 lists the technical parameters of a series of pixelated scintillation crystal films prepared according to the procedure described in Example 1, wherein:
  • Metal aluminum and silver are vacuum deposited, background vacuum 10"Pascal; deposition 200 nm; titanium dioxide and silicon dioxide using magnetron sputtering, oxygen flow SOsccm' argon flow 5 0 SCC m, sputtering power 3000W, time 5 minute;
  • 143x143 10 bismuth citrate is omnipotent. It can be observed in the above experimental results that the scintillation crystals grown on the surface of the pixel unit and the spacer have different morphologies, and the scintillation crystal film is introduced due to the introduction of the reflective material or the low refractive index material. The reflection of visible light is significantly enhanced.
  • a scintillation crystal pixelated film was prepared by the method of preparing a scintillation crystallized film by surface induced self-isolation technique provided in the scheme 2 described above, and the specific process is as follows -
  • step 2 Apply a layer of polyhydroxyethyl methacrylate to the surface of the substrate obtained in step 1.
  • the solvent is ethanol; Process, 3000 rpm, time 30 seconds, drying at 150 ° C for 30 minutes;
  • Table 4 lists the technical parameters of a series of pixelated scintillation crystal films prepared according to the procedure described in Example 7, wherein:
  • Metal aluminum and silver enamel are vacuum deposited, background vacuum is 10 4 Pascals; deposition is 200 nm; titanium dioxide and silicon dioxide are magnetron sputtering, oxygen flow rate is 20 sccm, argon flow rate is 50 sccm, sputtering power is 3000 W, time is 5 minutes;
  • a scintillation crystal pixelated film was prepared by the method of preparing a scintillation crystallized film by a surface induced self-isolation technique provided in the scheme 3 described above, and the specific process is as follows -
  • Figure 16 is a picture of the scintillation crystal film obtained in Example 13 under a transmission optical microscope
  • 2 is a scintillation crystal grown on the surface of PMMA, and has good light transmittance
  • 3 is a scintillation crystal grown on the surface of PVA, and has poor light transmittance. Play a light isolation effect.
  • Table 5 lists the technical parameters of a series of pixelated scintillation crystal films prepared according to the procedure described in Example 13, wherein - metal aluminum and silver ruthenium were vacuum deposited, background vacuum ltr 4 Pascals; deposition 200 nm; cerium oxide And silica ⁇ using magnetron sputtering, oxygen flow rate 20sc C m, argon flow rate 50sccm, sputtering power 3000W, time 5 minutes;
  • a method for preparing a surface-induced self-isolated scintillation crystal pixelated film is provided, and the specific process is as follows:
  • step 3 The surface of the substrate obtained in step 1 is coated with a layer of polyvinyl alcohol; the polyvinyl alcohol is formulated into an aqueous solution having a mass fraction of 4% before use; the application condition is a spin coating process, 3000 rpm, time 30 seconds, Dry at 150 ° C for 30 minutes;
  • the implementation conditions are oxygen flow lOOsccm, power 100W, etching time 3 minutes;
  • Csl cesium iodide
  • T1I cesium iodide
  • Figure 17 is a projection optical micrograph of the film obtained in Example 19, wherein 2 is a scintillation crystal grown on the surface of the silica, and the light transmittance is 3, which is a scintillation crystal grown on the surface of the polyvinyl alcohol, and the light transmittance is poor, which can Optical isolation effect.
  • Table 6 lists the technical parameters of a series of pixelated scintillation crystal films prepared according to the procedure described in Example 19, wherein:
  • Metal aluminum and silver crucibles are vacuum deposited, background vacuum 10 ⁇ 4 Pascals; deposition 200 nm; titanium dioxide and silica crucibles with magnetron sputtering, oxygen flow rate 20 sc C m , argon flow rate 50 s CC m, sputtering power 3000W, time 5 minutes;
  • the scintillation crystals grown on the surface of the pixel unit and the separator have different morphologies, and the scintillation crystals due to the introduction of reflective materials or low refractive index materials The reflection of the film on visible light is significantly enhanced.

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Abstract

一种像素化闪烁晶体薄膜及其制备方法和应用,包括:表面像素化基板(1),所述表面像素化基板(1)的表面由彼此分离的像素单元区(2)和位于像素单元间的隔离带区(3)构成;和闪烁晶体(5,6),其位于表面像素化基板上;在所述像素单元区(2)上的闪烁晶体具有第一形貌,所述隔离带区(3)内存在至少一条隔离带(4),在所述隔离带(4)上的闪烁晶体(5,6)具有和所述第一形貌不同的形貌。利用表面诱导自隔离技术制备的像素化闪烁晶体薄膜,可以减少相邻像素间可见光的干扰,有效提高薄膜成像时的空间分辨率。该薄膜的制备工艺简单,易于和现有光电检测系统集成,实现数字化检测。

Description

像素化闪烁晶体薄膜及其制备和应用 技术领域 本发明涉及一种晶体薄膜,尤其涉及一种像素化闪烁晶体薄膜及其制备和应 用。 背景技术 闪烁材料是一类将肉眼不可见的电磁波 (如紫外光, 伽马射线或者 X射线等) 转化为可见光的材料。 目前, 以闪烁材料为核心的探测和成像技术巳经广泛应用 于核医学、 安全检査、 工业无损探伤、 高能物理和空间物理等诸多方面。 但是, 闪烁材料吸收电磁波后产生的可见光具有发散性,严重降低了成像时的空间分辨 率
早期为了解决上述问题, 利用真空沉积技术, 通过工艺条件的控制, 将 烁 材料制成微柱状结构的闪烁晶体薄膜 (Detector utilizing a scintillator and photoconductive material, 美国专利 3,275,827, 1965年),将产生的可见光局限在微 柱状晶体内, 以降低光发散。 但是, 由于晶体微柱彼此间粘连, 使得其在高分辨 检测中受到限制。
近年来,为提高闪烁材料成像的空间分辨率,多将闪烁材料制成像素化薄膜, 并与电荷耦合器件 (charged coupled device, CCD)传感器、光电二极管 -薄膜晶体管 探测阵列、 互补金属氧化物半导体 (complementary Metal-Oxide-Semiconductor, CMOS)图像传感器等光电检测系统集成, 最终实现高分辨数字化检测。
目前, 将闪烁材料薄膜像素化的技术方案主要有以下 3种: 1、预先在基板表 面加工形成突起岛状结构, 每一个孤立的岛作为一个像素单元, 在真空沉积过程 中, 利用突起的岛形成的阴影遮挡效应, 使得闪烁材料只在岛上生长形成晶体, 岛与岛之间的缝隙没有闪烁材料生长 (Process of making structured x-ray phosphor screen, 美国专利 4,069,355, 1978年), 最终获得像素化闪烁晶体薄膜; 2、 先制 备完整的闪烁晶体薄膜,然后利用激光烧蚀等技术将完整的闪烁晶体薄膜刻蚀出 沟道, 剩余的闪烁晶体薄膜形成彼此分离的像素单元 (Method for fabricating pixelized phosphors, 美国专利 5,302,423, 1994年), 以实现像素化闪烁晶体料薄 膜; 3、 预先将基板制备成深孔结构的阵列, 然后将闪烁材料填充到深孔中 (Method of making a pixelized scintillation layer and structures incorporating same, 美国专利6,17723 1, 2001年), 每一个填充有闪烁材料的深孔作为一个像素单 元。
但是, 上述各种技术方案均存在不足之处, 具体如下:
方案 1 : 岛状结构在闪烁晶体薄膜厚度增加时, 岛与岛上的闪烁晶体彼此间 会粘连在一起, 使得分离的岛消失, 最终形成连续薄膜, 降低空间分辨率; 方案 2: 激光烧蚀设备昂贵, 工艺复杂, 成品率低;
方案 3 : 对基板材料要求严格, 制备微孔结构工艺复杂, 闪烁材料不易完全 填充满微孔内部。
因此,仍然需要开发一种空间分辨率高且制备工艺简单的像素化闪烁晶体薄 膜。
发明内容
为了实现上述目的,本发明人进行了深入细致的研究,结果出人意料地发现, 采用本发明独创的表面诱导自隔离方法可以有效消弱和阻挡像素单元中闪烁晶 体产生的可见光到达相邻像素单元, 而且方法简单, 无需昂贵的激光烧蚀设备。
本发明的第一个方面提供了一种像素化闲烁晶体薄膜, 其包括:
表面像素化基板,所述表面像素化基板的表面由彼此分离的像素单元区和位 于像素单元区之间的隔离带区构成,且每两个相邻像素单元区之间的隔离带区内 独立地包含 n条隔离带, 其中 n为大于等于 1的整数, 不同位置的隔离带区内的 隔离带条数 n可以相同或不同; 和
闪烁晶体, 其位于表面像素化基板上;
其特征在于, 在所述像素单元区上的闪烁晶体具有第一形貌,在所述隔离带 上的闪烁晶体具有第二形貌至第 (n+1)形貌, 并且所述第一形貌不同于所述第二 形貌至第 (n+1)形貌, 所述第二形貌至第 (n+1)形貌彼此可以相同, 也可以不同' 其中 n如上所定义。
本发明的第二个方面提供了一种像素化闪烁晶体薄膜的制备方法' 其包括: (1) 提供由像素单元区和隔离带区组成的表面像素化基板' 其中所述像素单 元区的表面适合生长具有第一形貌的晶体,所述相邻像素单元区之间的隔离带区 内包含 n条隔离带, 其中 n为大于等于 1的整数, 隔离带的表面适合生长形貌与 所述第一形貌不同的晶体,不同位置的隔离带区内的隔离带条数 n可以相同或不 同;
(2 ) 在所述像素单元区的表面生长具有第一形貌的晶体, 在所述隔离带的 表面生长具有不同于第一形貌的第二形貌至第 (n+1)形貌的晶体, 其中 n如上所 定义, 所述第二形貌至第 (n+1)形貌彼此可以相同, 也可以不同。
本发明的第三个方面提供了上述像素化闪烁晶体薄膜在紫外线检测、伽玛射 线检测和 X-射线检测中的应用。
本发明提供的表面诱导自隔离像素化闪烁晶体薄膜,可以有效提高薄膜成像 时的空间分辨率, 其制备工艺简单, 并易于与现有光电检测系统集成, 实现数字 化检测。
附图说明- 图 1 为表面像素化基板的表面示意图。
图 2 为图 1局部表面放大示意图。
图 3 为表面诱导自隔离像素化闪烁晶体薄膜的断面结构示意图。
图 4 为根据本发明一种具体实施方案的制备像素化闪烁晶体薄膜的过程的 示意图。
图 5 为根据本发明另一种具体实施方案的制备像素化闪烁晶体薄膜的过程 的示意图。
图 6 为根据本发明再一种具体实施方案的制备像素化闪烁晶体薄膜的过程 的示意图。
图 7 为根据本发明又一种具体实施方案的制备像素化闪烁晶体薄膜的过程 的示意图。
图 8为实施例 1的碘化铯 (換杂碘化铊)晶体薄膜在垂直入射光时透射光学显 微镜图。
图 9为图 8对应薄膜的倾转 45度角透射光学显微镜图。
图 10为图 8对应薄膜的断面扫描电镜图。
图 11为按实施例 1描述方法制备的典化铯 (擦杂碘化铊)晶体薄膜的透射光学 显微镜图, 其中像素单元区表面为玻璃, 隔离带表面为聚乙烯醇 (PVA;)。 图 12为图 11对应薄膜的断面扫描电镜图。
图 13 为按实施例 1所描述条件, 相同条件下分别在玻璃和聚乙烯醇表面真 空沉积 30μιη厚 CsI:TlI(10000:8)薄膜的透射光谱图。
图 14为图 13对应两种薄膜的 X射线衍射图。
图 15为实施例 7制备的闪烁晶体薄膜的断面扫描电镜图。
图 16为实施例 13备的闪烁晶体薄膜的透射光学显微镜图。
图 17 为实施例 19制备的闪烁晶体薄膜的透射光学显微镜图。
具体实施方式 除非另外指明, 本发明中术语 "像素化"是指将闪烁材料制备成彼此分离的 像素单元,像素单元内闪烁材料产生的可见光不会干扰相邻的像素单元, 从而实 现髙的空间分辨率。 术语 "闪烁晶体"是指由闪烁材料形成的晶体; 术语 "像素单元区"是指这样一种区域, 在该区域内生长的闪烁晶体作为像 素单元; 术语 "像素单元"是指闪烁晶体薄膜在成像时, 所成图像的最小完整釆枰所 对应的闪烁晶体; 术语 "隔离带区"是指像素单元区之间的区域, 并且相邻像素单元区之间的 隔离带区内存在至少一条隔离带; 术语"隔离带"是指隔离带区内表面性质与像素单元区表面性质不同的区域; 术语 "表面诱导"是指由于材料表面性质不同, 会诱导在其上生长的闪烁晶 体具有不同的形貌。 术语 "不同形貌"是指形成薄膜的晶体由于晶体结构、几何形状或者堆砌方 式不同, 表现出薄膜形貌上的差异, 具体可以表现为但不受限于至少以下一种 -
1、 薄膜的 X射线衍射图中衍射峰的数量不完全相同;
2、 薄膜的 X射线衍射图中衍射峰的位置不完全相同;
3、 薄膜的光学性质不同, 例如对可见光的透射率不同; 术语 "浸润性"是指液体与固体发生接触时, 液体在固体表面延展程度的一 种描述。 本发明的第一个方面提供了一种像素化闪烁晶体薄膜, 其包括: 表面像素化 基板,所述表面像素化基板的表面由彼此分离的像素单元区和位于像素单元间的 隔离带区构成; 和闪烁晶体, 其位于表面像素化基板上; 其特征在于在所述像素 单元区上的闪烁晶体具有第一形貌,所述隔离带区内存在至少一条隔离带,在所 述隔离带上的闪烁晶体具有和所述第一形貌不同的形貌。每两个相邻的像素单元 之间的隔离带内均可以包含一条或多条隔离带, 这些隔离带的长度和 /或宽度可 以相同或不同。 位于不同位置的隔离带可以具有相同或不同数量的隔离带。
因此, 本发明的像素化闪烁晶体薄膜包括:
表面像素化基板,所述表面像素化基板的表面由彼此分离的像素单元区和位 于像素单元区之间的隔离带区构成,且每两个相邻像素单元区之间的隔离带区内 独立地包含 n条隔离带, 其中 n为大于等于 1的整数, 各隔离带区内的隔离带条 数 n可以相同或不同; 和
闪烁晶体, 其位于表面像素化基板上;
其特征在于, 在所述像素单元区上的闪烁晶体具有第一形貌,在所述隔离带 上的闪烁晶体具有第二形貌至第 (n+1)形貌, 并且所述第一形貌不同于所述第二 形貌至第 (n+1)形貌, 所述第二形貌至第 (n+1)形貌彼此可以相同, 也可以不同, 其中 n如上所定义。
本发明中对于基板的材料没有特别的限制。可用作本发明基板材料的例子包 括但不限于玻璃、 陶瓷、金属、金属氧化物、聚合物、 二氧化硅、 石墨、氮化硅、 电荷耦合器件传感器、 光电二极管-薄膜晶体管探测阵列和互补金属氧化物半导 体图像传感器。 本发明对于基板的透明性无特殊要求, 但是优选釆用透明基板。
根据某些优选的实施方案, 所述像素单元区和隔离带区两者的表面性质不 同, 使得在相同条件下闪烁材料在上述两种表面生长获得不同形貌的晶体, 其中 在像素单元区上形成的具有第一形貌的晶体的可见光透射率高于在隔离带上形 成的具有第二形貌至第 (n+1)形貌的晶体的可见光透射率。 根据某些特别优选的 实施方案,所述像素单元和隔离带两者的表面性质应使得在像素单元上形成的具 有第一形貌的晶体的透射率比在隔离带上形成的具有第二形貌至第 形貌的 晶体的在相同条件下测量的透射率至少高 1%, 优选至少高 1.5%, 更优选至少高 2%. 进一步优选至少高 2.5%, 最优选至少高 3%, 按透射率的绝对差值计。 例 如, 对于在相同条件下生长的厚度均为 30μπΐ的两种闪烁晶体薄膜, 对于波长为 550am可见光的透射率,在像素单元上的晶体的透射率比在隔离带上的晶体的透 射率至少高 1%,优选至少高 1.5°/。,更优选至少高 2%,迸一步优选至少高 2.5%, 最优选至少高 3%。 像素单元区的几何形状没有特别限制, 可以根据具体应用要求加以设计。例 如, 根据某些优选的实施方案, 可以为矩形、 正方形、 三角形或六边形中任意一 种或多种。 像素单元几何形状也可以带有圆角 (即不是直角), 例如带有圆角的 矩形、 正方形、 三角形、 六边形等, 甚至可能是体育场形 (即两边为半圆中间为 长方形)。 根据某些更为优选的实施方案, 所述像素单元的几何形状的任意边的 长度不小于 10微米,不大于 500微米,更优选为 15-300微米,进一步优选为 20- 250 微米, 最优选为 25-150微米。 隔离带区的宽度和隔离带区内的隔离带的宽度没有特别限制,只要能够有效 地隔离所述相邻像素单元中闪烁材料产生的可见光即可。根据某些优选的实施方 案, 相邻像素单元间隔离带区的宽度不小于 1微米, 不大于 50微米, 更优选为 2-40微米, 进一步优选为 3-30微米, 最优选为 4-20微米, 隔离带区内隔离带的 宽度不小于 1微米, 不大于 50微米, 更优选为 2-40微米, 进一歩优选为 3-30 微米, 最优选为 4-20微米。 不同位置的隔离带可以具有相同或不同的宽度, 并没有特别限制。但是, 从 易操作性考虑, 优选不同位置的隔离带具有基本相同的宽度。本发明中对于隔离 带的数量没有特别限制。可以在全部或部分隔离带区内设置不止一条隔离带。本 发明中对于隔离带的几何形状没有特别限制,但必须保证由每个像素单元区单独 位于由隔离带围成的最小封闭几何形状内部, 所述"最小封闭几何形状"内部不 存在由隔离带围成的封闭几何形状; 当隔离带区内只存在一条隔离带时' 隔离带 的几何形状和尺寸与所在隔离带区的几何形状和尺寸相一致。 对于像素单元区表面材料和隔离带表面材料的种类没有特别限制,但它们的 表面材料应使得在所述像素单元区上形成的闪烁晶体的形貌不同于在所述隔离 带上形成的闪烁晶体的形貌。 虽然不愿受任何理论柬缚, 但是据信, 当像素单元区表面与要在其上生长的 闪烁材料的浸润性好于隔离带表面与闪烁^料的浸润性时,有利于在所述像素单 元区和隔离带上形成具有不同形貌的闪烁晶体,并且在所述像素单元区上形成的 闪烁晶体具有更高的透射率,而在隔离带上形成的晶体能够有效地隔离像素单元 内闪烁材料产生的可见光。根据某些优选的实施方案,像素单元区表面可以是与 闪烁材料具有良好浸润性的任意材料。 例如, 可以为选自玻璃、 陶瓷、 金属、 金 属氧化物、 聚合物、 二氧化硅、 石墨、 氮化硅和硅中的任意一种或任意几种的混 合物。相应地,隔离带表面可以是与闪烁材料具有较差浸润性的任意材料,例如, 隔离带表面可以是侧链带有羟基或者羧基的聚合物材料,也可以通过化学反应等 手段使得隔离带表面原本侧链不带漦基或者羟基的聚合物材料部分或者全部转 变为侧链带有羟基或者羧基的聚合物材料。 用于形成闪烁晶体的材料在本发明中没有特别的限制。这些材料的例子包括 伹不限于碘化铯、碘化钠,溴化铯、碘化锂、锗酸铋中任意一种或几种的混合物, 优选碘化铯、碘化钠和锗酸铋中任意一种或几种的混合物,更优选碘化铯和鹏化 钠中任意一种或两者的混合物。根据某些优选的实施方案, 为提高闪烁晶体的发 光效率, 闪烁晶体中可以含有掾杂材料。 掾杂材料的例子包括但不限于碘化铊、 溴化铕、 碘化钠、 碘化铕中一种或者几种的混合物。 根据某些优选的实施方案, 闪烁晶体材料-惨杂材料的组合可以为碘化铯-碘化钠、 碘化铯 -碘化铊、 碘化钠- 碘化铊、 溴化艳 -溴化铕和碘化锂-碘化铕中任意一种。 根据另外一些实施方案, 冈烁晶体材料 -掾杂材料的组合中可以同时釆用多种闪烁晶体材料和 /或同时釆用 多种掺杂材料。 闪烁晶体材料和惨杂材料的摩尔比没有特别限制,可以根据需要达到的闪烁 晶体的发光效率而定。根据某些优选的实施方案, 闪烁晶体材料和換杂材料的摩 尔比不小于 100: 1, 不大于 10000: 1, 该摩尔比更优选为 (150-8000):1 , 进一步 优选为 (200-5000): 1, 最优选为 C 1000-2000): 1 , 为提高像素化闪烁晶体薄膜对光利用率,可以在基板没有生长闪烁晶体的一 侧或者闪烁晶体表面以及缝隙间覆盖和填充反光物质或者折光指数小于所用闪 烁晶体的物质。 根据某些优选的实施方案,可以在基板没有生长闪烁晶体的一侧或者像素化 闪烁晶体薄膜的表面覆盖至少一层反光材料,薄膜中的缝隙可以部分或者全部被 所述反光材料填充, 所述反光材料用于减少闪烁晶体受激发产生的可见光的损 失。可用于本发明的反光材料的例子包括但不限于金属铝和金属银。对于反光材 料膜的厚度没有特别限制, 可以根据需要达到的反光效果而定, 例如, 可以大于
50纳米, 优选为大于 100纳米, 更优选为大于 200纳米。 优选地, 反光材料膜 的厚度不大于 1000纳米。 根据某些优选的实施方案,可以在基板没有生长闪烁晶体的一侧或者像素化 闪烁晶体薄膜的表面覆盖至少一层低折光指数材料,薄膜中缝隙可以部分或者全 部被所述低折光指数材料填充,所述低折光指数材料用于减少闪烁晶体受激发产 生的可见光的损失,所述低折光指数材料的折光指数小于所用闪烁晶体的折光指 数。 可用于本发明的低折光指数材料的例子包括但不限于二氧化钛和二氧化硅。 对于低折光指数材料膜的厚度没有特别限制, 可以根据需要达到的效果而定, 例 如, 可以大于 50纳米, 优选为大于 100纳米, 更优选为大于 200纳米。 优选地, 低折光指数材料膜的厚度不大于 1000纳米。 根据另外一些实施方案,可以在像素化闪烁晶体薄膜的表面分别覆盖至少一 层反光材料和至少一层低折光指数材料,也可以覆盖至少一层由反光材料和低折 光指数材料组成的混合物。 附图 1 是表面像素化基板的表面示意图, 其中 1是表面像素化基板, 其表 面由像素单元区 2和位于像素单元区之间的隔离带区 3构成。 附图 2是表面像素化基板的局部表面放大示意图,其中隔离带区 3内至少存 在 1条隔离带 4, 并且隔离带的表面性质与像素单元区的表面性质不同。 附图 3 是根据本发明某些实施方案的表面诱导自隔离像素化闪烁晶体薄膜 的断面示意图, 其中 1为表面像素化基板, 5和 6分别为在像素单元区和隔离带 表面生长的闪烁晶体。所述表面诱导是指由于表面像素化基板 1上像素单元区 2 和隔离带 5两者表面性质不同,会诱导闪烁材料在像素单元区 2表面生长获得的 闪烁晶体 5和在隔离带 4表面生长获得的闪烁晶体 6, 两者形貌不同。 其中, 像 素单元区 2表面与闪烁材料浸润性好, 两者间的接触角小于 90度, 闪烁材料易 生长形成直立的柱状结构晶体; 隔离带 4表面与闪烁材料浸润性不好, 两者间的 接触角大于 90度, 闪烁材料不易生长形成直立的柱状结构晶体。 所述自隔离是 指在表面像素化基板 1 上制备的闪烁晶体在基板表面的诱导下可以同时生长形 成两种不同形貌的晶体,制备工艺简单。在隔离带 4上生长的闪烁晶体 6有明显 的光隔离效果且空间尺寸小到纳米量级,达到提高薄膜空间分辨率的效果。同时, 利用隔离带所产生的光信号, 还可以提高薄膜成像时的敏感性。 尽管不愿受任何理论约束, 但是据信, 产生光隔离的原因可能有以下几个方 面:
1、 由于像素单元区 2上的闪烁晶体 5与隔离带 4上的闪烁晶体 6形貌不同 (例如, 在某些方案中, 前者是直立的柱状结构, 而后者是倾斜或弯曲的柱状结 构), 在薄膜制备的升降温过程中导致两类结构界面附近产生裂缝, 形成闪烁晶 体空气-闪烁晶体界面, 由于闪烁晶体的折光指数大于空气的折光指数, 因此像 素单元和隔离带上的闪烁晶体产生的可见光到达闪烁晶体 -空气界面发生全反 射, 光线被反射回两者内部, 从而达到光隔离的效果。
2、 在某些方案中, 在隔离带 4上生长的闪烁晶体 6具有倾斜或弯曲结构, 可以起到类似光学透镜的作用, 能够改变光的传播方向, 对来自近邻像素单元的 很宽角度范围内光具有捕获作用, 实现隔离近邻像素单元光干扰效果。 3、 在某些方案中, 在隔离带 4上生长的闪烁晶体 6具有倾斜或弯曲结构, 可以起到类似光导纤维的作用,能够将在隔离带上生长的闪烁晶体所产生的光汇 聚传输到隔离带和近邻像素单元上,能充分利用隔离带上生长的闪烁晶体所产生 的光信号, 达到提高敏感性的效果。
4、 在某些方案中, 在隔离带 4上生长的闪烁晶体 6光学透过性差' 阻碍了 相邻像素单元内闪烁晶体产生的可见光的传播, 从而达到光隔离的效果。 本发明的第二个方面提供了一种像素化闪烁晶体薄膜的制备方法' 其包括: (1)提供由像素单元区和隔离带区组成的表面像素化基板' 其中所述像素单 元区的表面适合生长具有第一形貌的晶体,所述相邻像素单元区之间的隔离带区 内包含 n条隔离带, 其中 n为大于等于 1的整数, 隔离带的表面适合生长形貌与 所述第一形貌不同的晶体,不同位置的隔离带区内的隔离带条数 n可以相同或不 同;
(2) 在所述像素单元区的表面生长具有第一形貌的晶体, 在所述隔离带的 表面生长具有不同于第一形貌的第二形貌至第 (n+1)形貌的晶体, 其中 n如上所 定义, 所述第二形貌至第 (n+1)形貌彼此可以相同, 也可以不同。 根据某些优选的实施方案 (如图 4所示, 下文中称为方案 1, 为方便理解, 图 4中所用隔离带的几何形状和大小与隔离带区的几何形状和大小完全相同,但 是实施时可以不同), 本发明的像素化闪烁晶体薄膜的制备方法包括如下步骤:
(1) 在基板表面覆盖至少一层能够提高或降低基板表面与闪烁材料浸润性 的表面材料 7;
(2) 利用掩模刻蚀技术去掉部分表面材料 7, 暴露出相应的基板表面, 形成 由像素单元区和隔离带区组成的表面像素化基板;
(3) 在表面像素化基板上生长出由闪烁材料和任选的惨杂材料形成的闪烁 晶体, 形成像素化闪烁晶体薄膜。 根据某些优选的实施方案 (如图 5所示, 下文中称为方案 2, 为方便理解, 图 5中所用隔离带的几何形状和大小与隔离带区的几何形状和大小完全相同,伹 是实施时可以不同), 本发明的像素化闪烁晶体薄膜的制备方法包括如下步骤:
(1) 利用掩模刻蚀技术, 将基板表面加工形成所需像素化图形;
(2) 在 (1)形成的基板表面覆盖至少一层能够提髙或降低基板表面与闪烁材 料浸润性的表面材料 7;
(3) 利用刻蚀技术去掉部分表面材料 7, 暴露出基板表面, 形成由像素单元 区和隔离带区组成的表面像素化基板;
(4) 在表面像素化基板上生长出由闪烁材料和任选的揍杂材料形成的闪烁 晶体, 形成像素化闪烁晶体薄膜。 根据某些优选的实施方案 (如图 6所示, 下文中称为方案 3, 为方便理解, 图 6中所用隔离带的几何形状和大小与隔离带区的几何形状和大小完全相同,但 是实施时可以不同), 本发明的像素化闪烁晶体薄膜的制备方法包括如下步骤:
(1)在基板表面依次覆盖第一种表面材料 7和第二种表面材料 8, 所述第二 种表面材料 8能够提高或者降低第一种表面材料 7与闪烁材料的浸润性;
(2)利用掩模刻蚀技术去掉部分第一种表面材料 7, 暴露出第二种表面材料 8的相应表面, 形成由像素单元区和隔离带区组成的表面像素化基板;
(3) 在表面像素化基板上生长出由闪烁材料和任选的掺杂材料形成的闪烁 晶体, 形成像素化闪烁晶体薄膜。 根据某些优选的实施方案 (如图 7所示, 下文中称为方案 4, 为方便理解, 图 7中所用隔离带的几何形状和大小与隔离带区的几何形状和大小完全相同,但 是实施时可以不同), 本发明的像素化闪烁晶体薄膜的制备方法包括如下步骤:
(1)在基板表面覆盖第一种表面材料 7 ;
(2) 利用掩模刻蚀技术去掉部分第一种表面材料 7, 形成像素化图形; (3)在 (2)形成的基板上覆盖能够提高或降低第一种表面材料 7表面与闪烁材 料浸润性的第二种表面材料 8 ;
(4) 利用刻蚀技术去掉部分第二种表面材料 8, 暴露出第一种表面材料 7的 相应表面, 形成由像素单元区和隔离带区组成的表面像素化基板;
(5) 在表面像素化基板上生长出由闪烁材料和任选的掾杂材料形成的闪烁 晶体, 形成像素化闪烁晶体薄膜。 对于在表面像素化基板上生长出由闪烁材料和任选的擦杂材料形成的闪烁 材料晶体的技术, 本发明没有特别限制。例如, 可以利用真空共沉积技术, 在表 面像素化基板上沉积闪烁材料和任选的掾杂材料, 形成像素化闪烁晶体薄膜。 为提高像素化闪烁晶体薄膜对光利用率,可以在基板没有生长闪烁晶体的一 侧或者闪烁晶体表面以及缝隙间覆盖和填充反光物质或者折光指数小于所用闪 烁晶体的物质。 根据某些优选的实施方案,可以在基板没有生长闪烁晶体的一侧或者像素化 闪烁晶体薄膜的表面覆盖至少一层反光材料,薄膜中的缝隙可以部分或者全部被 所述反光材料填充, 所述反光材料用于减少闪烁晶体受激发产生的可见光的损 失。可用于本发明的反光材料的例子包括但不限于金属铝和金属银。对于反光材 料膜的厚度没有特别限制, 可以根据需要达到的反光效果而定, 例如, 可以大于 50纳米, 优选为大于 100纳米, 更优选为大于 200纳米。 优选地, 反光材料膜 的厚度不大于 1000纳米。 根据某些优选的实施方案,可以在基板没有生长闪烁晶体的一侧或者像素化 闪烁晶体薄膜的表面覆盖至少一层低折光指数材料,薄膜中缝隙可以部分或者全 部被所述低折光指数材料填充,所述低折光指数材料用于减少闪烁晶体受激发产 生的可见光的损失,所述低折光指数材料的折光指数小于所用闪烁晶体的折光指 数。 可用于本发明的低折光指数材料的例子包括但不限于二氧化鈦和二氧化硅。 对于低折光指数材料膜的厚度没有特别限制, 可以根据需要达到的效果而定,例 如, 可以大于 50纳米, 优选为大于 100纳米, 更优选为大于 200纳米。优选地, 低折光指数材料膜的厚度不大于 1000纳米。 根据另外一些实施方案,可以在像素化闪烁晶体薄膜的表面分别覆盖至少一 层反光材料和至少一层低折光指数材料,也可以覆盖至少一层由反光材料和低折 光指数材料组成的混合物。 本发明的第三个方面提供了上述像素化闪烁晶体薄膜在紫外线检测、 X-射线 检测和伽马射线检测中的应用。本发明的表面诱导自隔离像素化闪烁晶体薄膜可 以和现有光电检测系统, 如电荷耦合器件传感器 (CCD 传感器), 光电二极管-薄 膜晶体管探测阵列, 互补金属氧化物半导体图像传感器 (CMOS图像传感器)等集 成, 广泛的应用于紫外线、 X-射线和伽马射线等方面的检测。 根据某些实施方案, 本发明的像素化闪烁晶体薄膜可以将 X射线转化为可 见光, 并与电荷耦合器件传感器、 光电二极管-薄膜晶体管探测阵列、 或互补金 属氧化物半导体图像传感器进行集成, 实现数字化检测。 根据某些实施方案,本发明的像素化闪烁晶体薄膜可以将紫外线转化为可见 光, 并与电荷耦合器件传感器、 光电二极管-薄膜晶体管探测阵列、 或互补金属 氧化物半导体图像传感器进行集成, 实现数字化检测。 根据某些实施方案,本发明的像素化闪烁晶体薄膜可以将伽马射线转化为可 见光' 并与电荷耦合器件传感器、 光电二极管-薄膜晶体管探测阵列、 或互补金 属氧化物半导体图像传感器进行集成, 实现数字化检测。 釆用本发明独创的表面诱导自隔离方法得到的像素化闪烁晶体薄膜,可以有 效提高薄膜成像时的空间分辨率,其制备工艺简单, 并易于与现有光电检测系统 集成, 实现数字化检测。 实施例 本发明所使用的试剂、 规格和来源列于表 1中 表 1
Figure imgf000015_0001
聚乙烯醇 (PVA) 563900-500G Sigma-Aldrich公司 聚甲基丙稀酸甲酯
200336-100G Sigma- Aldrich公司 (PMMA) 聚甲基丙烯酸羟乙酯 529265- 5G Sigma-Aldrich公司 光刻胶 RZJ-304 苏州瑞红电子化学品有限公司 显影液 KMP PD238-II 北京科华微电子有限公司 丙酮 分析纯 北京化工厂 分析纯 北京化工厂 盐酸 体积分数 35% 北京化工厂 氢氟酸 体积分数 30% 北京化工厂
所用设备、 型号和厂商列于表 2中 表 2
Figure imgf000016_0001
旋涂设备 KW-4A 中科院微电子所 等离子设备 SY型 500W 中科院微电子中心 磁控溅射设备 BLADE-FEV 东莞宏威数码机械有限公司 实施例 1
采用上文中描述的方案 1 提供的通过表面诱导自隔离技术制备闪烁晶体像 素化薄膜的方法制备闪烁晶体像素化薄膜, 其具体过程如下-
1、 在 100克水中依次加入 4克 PVA和 4克重铬酸铵配成溶液;
2、 将上述配好的溶液涂布在氮化硅基板表面, 实施条件为采用旋涂技术, 3000转 /分钟, 时间 30秒;
3、 在涂有 PVA的基板上加掩模版,紫外光下曝光 10秒后,将基板置于 75°C 热水中漂洗 30秒, 将未交联的 PVA洗掉并暴露出氮化硅表面, 其中氮 化硅作为像素单元区, PVA作为隔离带;
4、 利用真空沉积技术, 将碘化铯 (Csl)和碘化铊 (T1I)共沉积到像素化基板表 面, 两者摩尔比为 Ϊ000Ο: 8, 沉积速率每小时 60微米, 沉积时间 1小 时, 其中基板温度 300°C, 本底真空度 10^帕斯卡。
图 8是依照实施例 1在氯化硅基板表面生长的 CsI:TlI(10000:8)薄膜的透射光 学显微镜图 (平行光垂直薄膜入射)。 其中像素单元区表面为氮化硅, 隔离带表 面为 PVA, 隔离带宽度 10微米; 2为在像素单元区表面生长的闪烁晶体, 光学 透过性较好, 3为在隔离带表面生长的闪烁晶体, 光学透过性较差, 可以起到明 显光隔离效果。
图 9是图 8对应薄膜透射光学显微镜图, 平行光与薄膜成 45°角。 2为在像 素单元区表面生长的闪烁晶体, 光学透过性较好, 3为在隔离带表面生长的闪烁 晶体, 光学透过性较差, 可以起到明显光隔离效果。
对比图 8和图 9可以看到,在隔离带表面上生长的闪烁晶体对不同方向的可 见光都有良好的隔离效果。
从图 8计算出薄膜的空间分辨率为 5.5线对 /毫米,较现有 3.5线对 /毫米的闪 烁晶体薄膜在空间分辨率上有很大提高。 图 10为图 8对应薄膜的断面扫描电镜图。 其中 2为在像素单元区表面生长 的闪烁晶体, 3为在隔离带表面生长的闪烁晶体,两种晶体形貌间存在明显差异, 在两种晶体界面处, 可以观察到由于两种晶体内部应力不同产生的裂缝。
图 11是依照方案 1所述方法在玻璃基板表面生长 CsI:TlI(l 0000:8)薄膜透射 光学显微镜图。其中像素单元区表面为玻璃, 隔离带表面为 PVA, 隔离带宽度分 别为 50和 35微米; 2为在像素单元区表面生长的闪烁晶体, 光学透过性较好, 3为在隔离带表面生长的闪烁晶体, 光学透过性较差。
图 12为图 11对应薄膜的断面扫描电镜图。其中 2为在像素单元区表面生长 的闪烁晶体, 3为在隔离带表面生长的闪烁晶体,两种晶体形貌间存在明显差异, 在两种晶体界面处, 可以观察到由于两种晶体内部应力不同产生的裂缝。
图 13为在相同条件下在玻璃和 PVA表面真空沉积 30μιη厚 CsI:TI(l 0000:8) 的透射光谱图。 由图中可见, 在相同条件下, 在两种表面生长的两种不同形貌的 闪烁晶体薄膜的透射率不同。例如, 厚度为 30μπα的这两种闪烁晶体薄膜对于波 长为 400- 800nm范围内的可见光的透射率的差值均不低于 1%。 对于硅光电检测 器件最敏感的波长 550nm, 可见光的透射率的差值高达约 4%。
图 14为图 13对应两种薄膜的 X射线衍射图, 从图中看出, 在 PVA表面生 长的闪烁晶体薄膜存在 4个明显的衍射峰,而在玻璃表面生长的闪烁晶体薄膜存 在 3个明显的衍射峰。 同时两薄膜中相同位置衍射峰的强度也不相同。衍生峰的 存在说明薄膜内闪烁材料形成晶体,衍射峰位置和强度的差异说明了两薄膜内晶 体组成和堆砌方式不同。
实施例 2-6
表 3列出一系列按实施例 1描述的过程制备的像素化闪烁晶体薄膜的技术参 数, 其中:
金属铝和银采用真空沉积, 本底真空度 10" 帕斯卡; 沉积 200纳米; 二氧化鈦和二氧化硅采用磁控溅射, 氧气流量 SOsccm' 氩气流量 50SCCm, 溅射功率 3000W, 时间 5分钟;
表 3 髓 主体 惨 主体材料
隔离带宽度 反光 低折光 单元尺寸 材料 杂 与掺杂剂
(单位: 微米) 材料 指数材料
(单位:微米) 剂 的摩尔比
500x500 50 Csl Nal 1000 3 无 二氧化硅
160x190 15 Nal T1I 10000 1 无 二氧化钛
10x10 1 CsBr EuBr 100 1 银 无
320x240 25 Lil Eul 1000 6 铝 无
143x143 10 锗酸铋 无 一 无 无 上述实验结果中均可以观察到,在像素单元和隔离带表面生长的闪烁晶体具 有不同的形貌, 同时由于反光材料或者低折光指数材料的引入, 闪烁晶体薄膜对 可见光的反射明显增强。
实施例 7
采用上文中描述的方案 2 提供的通过表面诱导自隔离技术制备闪烁晶体像 素化薄膜的方法制备闪烁晶体像素化薄膜, 其具体过程如下-
1、 在金属 A1 基板表面涂布一层光刻胶, 实施条件为采用旋涂工艺, 3000 转 /分, 时间 30秒, 80°C烘干 10分钟后加掩模版紫外光下曝光 10秒钟, 在去胶液中浸泡 10秒钟去胶, 清水冲洗后烘干; 将烘干后的基板浸泡在 体积分数为 10%的盐酸中 2分钟后捞出并用清水将残留盐酸洗净后用氮 气吹干表面; 上述基板浸泡在丙酮中漂洗 30秒后捞出, 并用氮气吹干基 板表面;
2、 在步骤 1获得的基板表面涂布一层聚甲基丙烯酸羟乙酯; 使用前将聚甲 基丙烯酸羟乙酯配制成质量分数 2%的溶液,溶剂为乙醇; 实施条件为采 用旋涂工艺, 3000转 /分, 时间 30秒, 150°C烘千 30分钟;
3、 利用氧等离子刻蚀技术去掉部分聚甲基丙烯酸羟乙酯, 暴露出 A1形成像 素单元区, 余下的聚甲基丙烯酸羟丙酯形成隔离带, 实施条件为氧气流量 100s ' 功率 100W, 刻蚀时间 3分钟;
4、 利用真空沉积技术, 将碘化铯 (Csl)和碘化铊 (T1I)共沉积到像素化基板表 面, 两者摩尔比为 10000: 8, 沉积速率每小时 60微米厚度, 沉积时间 1 小时, 其中基板温度 300°C, 本底真空度 10" 帕斯卡。 图 15为实施例 7制备的闪烁晶体薄膜的断面扫描电镜图。 2为在像素单元 区上生长的闪烁晶体, 3为在隔离带上生长的闪烁晶体。 在两种不同表面生长的 闪烁晶体具有不同的形貌, 并且在两者的界面处存在裂缝。
实施例 8-12
表 4列出一系列按实施例 7描述的过程制备的像素化闪烁晶体薄膜的技术参 数, 其中:
金属铝和银釆用真空沉积, 本底真空度 104帕斯卡; 沉积 200纳米; 二氧化钛和二氧化硅采用磁控溅射, 氧气流量 20sccm, 氩气流量 50sccm, 溅射功率 3000W, 时间 5分钟;
表 4
Figure imgf000020_0001
上述实验结果中均可以观察到,在像素单元和隔离带表面生长的闪烁晶体具 有不同的形貌。
实施例 13
采用上文中描述的方案 3 提供的通过表面诱导自隔离技术制备闪烁晶体像 素化薄膜的方法制备闪烁晶体像素化薄膜, 其具体过程如下-
1、 在光电二极管-薄膜晶体管探测阵列表面涂布一层 PMMA, 使用前将 PMMA配制成质量分数 2%的溶液, 溶剂为丙酮, 实施条件为釆用旋涂 工艺, 3000转 /分, 时间 30秒; 80°C烘干 10分钟;
2、 在 100克水中依次加入 4克 PVA和 4克重铬酸铵配成溶液;
3、 将上述配好的溶液涂布在 PMMA表面,实施条件为采用旋涂技术, 3000 转 /分钟, 时间 30秒; 4、 在涂有 i>VA的基板上加掩模版,紫外光下曝光 10秒后,将基板置于 75。C 热水中漂洗 30秒, 将未交联的 PVA洗掉并暴露出 PMMA表面, 其中 PMMA作为像素单元区, PVA作为隔离带;
5、 利用真空沉积技术,将碘化铯 (Csl)和碘化铊 (T1I)共沉积到像素化基板表 面, 两者摩尔比为 10000: 8, 沉积速率每小时 60微米厚度, 沉积时间 1 小时, 其中基板温度 300°C, 本底真空度 10"4帕斯卡。
图 16为实施例 13中获得的闪烁晶体薄膜在透射光学显微镜下的图片, 2为 在 PMMA表面生长的闪烁晶体, 透光性好, 3为在 PVA表面生长的闪烁晶体, 透光性差, 可以起到光隔离效果。 同时, 根据需要, 在横向隔离带区内存在两条 由 PVA形成的隔离带, 纵向隔离带区内仅有一条由 PVA形成的隔离带。
实施例 14-18
表 5列出一系列按实施例 13描述的过程制备的像素化闪烁晶体薄膜的技术 参数, 其中- 金属铝和银釆用真空沉积, 本底真空度 ltr4帕斯卡; 沉积 200纳米; 二氧化钕和二氧化硅釆用磁控溅射, 氧气流量 20scCm, 氩气流量 50sccm, 溅射功率 3000W, 时间 5分钟;
表 5
Figure imgf000021_0001
上述实验结果中均可以观察到,在像素单元和隔离带表面生长的闪烁晶体具 有不同的形貌, 同时由于反光材料或者低折光指数材料的引入, 闪烁
可见光的反射明显增强。 按本发明提供的一种表面诱导自隔离闪烁晶体像素化薄膜的制备方法,釆用 方案 4, 其具体过程如下:
1、 在玻璃基板表面溅射一层二氧化硅, 实施条件为氧气流量 20SCCm, 氩气 流量 50sccm, 溅射功率 3000W, 时间 2分钟;
2、 在二氧化硅表面涂布一层光刻胶, 实施条件为采用旋涂工艺, 3000 转 / 分, 时间 30秒, 80°C烘干 10分钟后加掩模版紫外光下曝光 10秒钟, 在去胶液 中浸泡 10秒钟去胶, 清水冲洗后烘干; 将烘干后的基板浸泡在体积分数为 10% 的氢氟酸中 2分钟后捞出并用清水将残留氢氟酸洗净后用氮气吹干表面;上述基 板浸泡在丙酮中漂洗 30秒后捞出, 并用氮气吹千基板表面;
3、 在步骤 1获得的基板表面涂布一层聚乙烯醇; 使用前将聚乙烯醇配制成 质量分数 4%的水溶液;实施条件为釆用旋涂工艺, 3000转 /分,时间 30秒, 150°C 烘千 30分钟;
4、 利用氧等离子刻蚀技术去掉部分聚乙烯醇, 暴露出二氧化硅形成像素单 元区, 余下的聚乙烯醇形成隔离带, 实施条件为氧气流量 lOOsccm, 功率 100W, 刻蚀时间 3分钟;
5、利用真空沉积技术,将碘化铯 (Csl)和碘化铊 (T1I)共沉积到像素化基板表面, 两者摩尔比为 10000: 8, 沉积速率每小时 60微米厚度, 沉积时间 1小时, 其中 基板温度 300°C, 本底真空度 10— 4帕斯卡。
图 17为实施例 19获得薄膜的投射光学显微镜图,其中 2为在二氧化硅表面 生长的闪烁晶体, 透光性, 3为在聚乙烯醇表面生长的闪烁晶体, 透光性差, 可 以起到光隔离效果。
实施例 20-24
表 6列出一系列按实施例 19描述的过程制备的像素化闪烁晶体薄膜的技术 参数, 其中:
金属铝和银釆用真空沉积, 本底真空度 10·4帕斯卡; 沉积 200纳米; 二氧化鈦和二氧化硅釆用磁控溅射, 氧气流量 20scCm, 氩气流量 50sCCm, 溅射功率 3000W, 时间 5分钟;
表 6 m
王体 主体材料
隔离带宽度 反光 低折光 单元尺寸 材料 杂 与擦杂剂
(单位: 微米) 材料 指数材料
(单位:微米) 剂 的摩尔比
500x500 50 Csl Nal 1000: 3 无 二氧化硅
160x 190 15 Nal Til 10000: 1 无 二氧化鈦
10x 10 1 CsBr EuBr 100: 1 银 无
320x240 25 Lil Eul 1000; 6 无
143x 143 10 锗酸铋 无 ― 无 无 上述实验结果中均可以观察到,在像素单元和隔离带表面生长的闪烁晶体具 有不同的形貌, 同时由于反光材料或者低折光指数材料的引入, 闪烁晶体薄膜对 可见光的反射明显增强。

Claims

权利 要 求 书
1. 一种像素化闪烁晶体薄膜, 其包括:
表面像素化基板,所述表面像素化基板的表面由彼此分离的像素单元区和位 于像素单元区之间的隔离带区构成,且每两个相邻像素单元区之间的隔离带区内 独立地包含 η条隔离带, 其中 η为大于等于 1的整数, 不同位置的隔离带区内的 隔离带条数 η可以相同或不同; 和
闪烁晶体, 其位于表面像素化基板上;
其特征在于,在所述像素单元区上的闪烁晶体具有第一形貌, 在所述隔离带 上的闪烁晶体具有第二形貌至第 (η+Ι)形貌, 并且所述第一形貌不同于所述第二 形貌至第 (η+1)形貌, 所述第二形貌至第 (η+1)形貌彼此可以相同, 也可以不同, 其中 η如上所定义。
2. 根据权利要求 1 的像素化闪烁晶体薄膜, 其中所述基板为玻璃、 陶瓷、 金属、 金属氧化物、 聚合物、 二氧化硅、 石墨、 氮化硅、 电荷耦合器件传感器、 光电二极管 -薄膜晶体管探测阵列和互补金属氧化物半导体图像传感器中一种。
3. 根据权利要求 1 的像素化闪烁晶体薄膜, 其中所述像素单元的几何形状 的任意边的长度不小于 10微米, 不大于 500微米。
4. 根据权利要求 1 的像素化闪烁晶体薄膜, 其中所述隔离带区的宽度不小 于 1微米, 不大于 50微米。
5. 根据权利要求 1的像素化闪烁晶体薄膜,其中所述形貌不同是指晶体的 X 射线衍射图谱不同。
6. 根据权利要求 5的像素化闪烁晶体薄膜, 其中所述 X射线衍射图谱不同 是指特征衍射峰数量或位置中至少一项不同。
7. 根据权利要求 1 的像素化闪烁晶体薄膜, 其中所述像素单元区的表面材 料选自玻璃、 陶瓷、 金属、 金属氧化物、 聚合物、 二氧化硅、 石墨、 氮化硅和硅 中的任意一种或任意几种的混合物。
8. 根据权利要求 1 的像素化闪烁晶体薄膜, 其中所述隔离带的表面材料包 含侧链带有羟基和 /或羧基的聚合物材料。
9. 根据权利要求 1 的像素化闪烁晶体薄膜, 其中用于形成闪烁晶体的材料 为碘化艳、 碘化钠, 溴化铯、 碘化锂、 锗酸铋中任意一种或任意几种的混合物。
10. 根据权利要求 1的像素化闪烁晶体薄膜,其中闪烁晶体中含有掾杂材料。
11. 根据权利要求 1的像素化闪烁晶体薄膜,其中闪烁晶体材料 -換杂材料的 组合为碘化铯-碘化钠、 碘化铯-碘化铊、 碘化钠-碘化铊、 溴化铯-溴化铕和碘化 锂-碘化铕中任意一种。
12. 根据权利要求 1的像素化闪烁晶体薄膜, 其中闪烁晶体材料和換杂材料 的摩尔比为(100-10000):1。
13. 根据权利要求 1的像素化闪烁晶体薄膜, 其中在基板没有生长闪烁晶体 的一侧或者闪烁晶体表面以及缝隙间覆盖和填充反光材料和 /或折光指数小于所 用闪烁晶体的低折光指数材料。
14. 根据权利要求 13 的像素化闪烁晶体薄膜, 其中反光材料选自金属铝、 金属银和其混合物。
15. 根据权利要求 13 的像素化闪烁晶体薄膜, 其中低折光指数材料选自二 氧化钛、 二氧化硅或其混合物。
16. 根据权利要求 13 的像素化闪烁晶体薄膜, 其中在像素化闪烁晶体薄膜 的表面分别覆盖至少一层反光材料和至少一层低折光指数材料。
17. 一种制备根据权利要求 1-16 中任一项的像素化闪烁晶体薄膜的制备方 法, 其包括:
(1)提供由像素单元区和隔离带区组成的表面像素化基板, 其中所述像素单 元区的表面适合生长具有第一形貌的晶体,所述相邻像素单元区之间的隔离带区 内包含 n条隔离带,其中 n为大于等于 1的整数, 隔离带的表面适合生长形貌与 所述第一形貌不同的晶体,不同位置的隔离带区内的隔离带条数 n可以相同或不 同;
(2) 在所述像素单元区的表面生长具有第一形貌的晶体, 在所述隔离带的 表面生长具有不同于第一形貌的第二形貌至第 (n+1)形貌的晶体, 其中 n如上所 定义, 所述第二形貌至第 (n+1)形貌彼此可以相同, 也可以不同。
I S. 根据权利要求 17 的像素化闪烁晶体薄膜的制备方法, 其中所述像素单 元区和隔离带区两者的表面性质不同,使得在相同条件下闪烁材料在上述两种表 面生长获得具有不同 X射线衍射图谱的晶体。
19. 根据权利要求 17的像素化闪烁晶体薄膜的制备方法, 其中所述像素单 元区表面与要在其上生长的闪烁材料的浸润性好于隔离带表面与闪烁材料的浸 润性。
20. 根据权利要求 17的像素化闪烁晶体薄膜的制备方法, 其中像素单元区 表面与闪烁材料间的接触角小于 90度, 使得闪烁材料生长形成直立的柱状结构 晶体; 隔离带表面与闪烁材料间的接触角大于 90度, 使得闪烁材料不能生长形 成所述直立的柱状结构晶体, 而是形成倾斜或弯曲结构的闪烁晶体。
21. 一种制备根据权利要求 1-16中任一项的像素化闪烁晶体薄膜的制备方 法, 其包括:
(1) 在基板表面覆盖至少一层能够提高或降低基板表面与闪烁材料浸润性 的表面材料; (2) 利用掩模刻蚀技术去掉部分表面材料, 暴露出相应的基板表面, 形成由 像素单元区和隔离带区组成的表面像素化基板;
(3) 在表面像素化基板上生长出由闪烁材料和任选的換杂材料形成的闪烁 晶体, 形成像素化闪烁晶体薄膜。
22. 一种制备根据权利要求 1-16 中任一项的像素化闪烁晶体薄膜的制备方 法, 其包括-
(1) 利用掩模刻蚀技术, 将基板表面加工形成所需像素化图形;
(2) 在 (1)形成的基板表面覆盖至少一层能够提高或降低基板表面与闪烁材 料浸润性的表面材料;
(3) 利用刻蚀技术去掉部分表面材料, 暴露出基板表面, 形成由像素单元区 和隔离带区组成的表面像素化基板;
(4) 在表面像素化基板上生长出由闪烁材料和任选的惨杂材料形成的闪烁 晶体, 形成像素化闪烁晶体薄膜。
23.一种制备根据权利要求 1-16 中任一项的像素化闪烁晶体薄膜的制备方 法, 其包括:
0)在基板表面依次覆盖第一种表面材料和第二种表面材料, 所述第二种表 面材料能够提高或者降低第一种表面材料与闪烁材料的浸润性;
(2) 利用掩模刻蚀技术去掉部分第一种表面材料, 暴露出第二种表面材料的 相应表面, 形成由像素单元区和隔离带区组成的表面像素化基板;
(3) 在表面像素化基板上生长出由闪烁材料和任选的惨杂材料形成的闪烁 晶体, 形成像素化闪烁晶体薄膜。
24.一种制备根据权利要求 1-16 中任一项的像素化闪烁晶体薄膜的制备方 法, 其包括-
(1) 在基板表面覆盖第一种表面材料;
(2) 利用掩模刻蚀技术去掉部分第一种表面材料, 形成像素化图形;
(3) 在 (2)形成的基板上覆盖能够提高或降低第一种表面材料表面与闪烁材 料浸润性的第二种表面材料;
(4)利用刻蚀技术去掉部分第二种表面材料, 暴露出第一种表面材料的相应 表面, 形成由像素单元区和隔离带区组成的表面像素化基板;
(5) 在表面像素化基板上生长出由闪烁材料和任选的惨杂材料形成的闪烁 晶体, 形成像素化闪烁晶体薄膜。
25. 根据权利要求 1-16中任一项所述的像素化闪烁晶体薄膜在紫外线检测、
X-射线检测和伽马射线检测中的应用。
PCT/CN2012/075570 2012-05-16 2012-05-16 像素化闪烁晶体薄膜及其制备和应用 WO2013170455A1 (zh)

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