Ultraviolet absorption enhanced semiconductor film and preparation method and application thereof

Abstract

The invention provides an ultraviolet absorption enhancement type semiconductor film and a preparation method and application thereof. The ultraviolet absorption enhancement type semiconductor film comprises a substrate, an aluminum middle layer and an aluminum nitride dielectric layer, wherein the aluminum middle layer and the aluminum nitride dielectric layer are sequentially arranged on the surface of one side of the substrate in a stacked mode. According to the ultraviolet absorption enhanced semiconductor film, the reflection of the upper surface of the ultraviolet absorption enhanced semiconductor film with the thickness of several nanometers tends to zero under the combined action of interface phase shift and absorption phase shift, so that the light absorption of the semiconductor layer is increased. The light absorption intensity is enhanced under the condition that the thickness of the ultraviolet absorption enhanced semiconductor film is ensured to be small, so that the response speed of the photoelectric detector is improved.

Description

Technical Field

[0001] The invention belongs to the technical field of semiconductor materials and relates to an ultraviolet absorption enhanced semiconductor film and a preparation method and application thereof. Background Art

[0002] Ultraviolet detectors are widely used in the fields of ultraviolet radiation measurement, ozone monitoring, air pollution monitoring, space communication, aircraft guidance, blood analysis, mercury lamp disinfection monitoring, etc. An ideal semiconductor detector needs to have the following characteristics: high sensitivity, high responsiveness, high signal-to-noise ratio, high spectral selectivity, high speed, and high stability.

[0003] Aluminum nitride (AlN) material has the characteristics of high temperature resistance, good chemical stability, and large bandgap width. Its bandgap width is 6.2eV, corresponding to an absorption wavelength of 200nm, and it is an excellent candidate material for vacuum band deep ultraviolet detectors. AlN vacuum photodetectors based on Schottky junctions have the advantages of small size, fast response speed, low energy consumption, and natural cutoff band edges. They are of great significance for responding to space weather and monitoring space disasters such as the occurrence and changes of solar storms. They are helpful to the development of solar-terrestrial physics and geospace science, and have broad application prospects.

[0004] CN119050173A An aluminum nitride vacuum detector comprises: a sapphire substrate; an aluminum nitride buffer layer, an aluminum nitride epitaxial layer and an n-type aluminum gallium nitride layer stacked in sequence along a first direction on the sapphire substrate; an aluminum nitride layer, a silicon dioxide insulating film and a first metal contact layer arranged in parallel along a second direction on a side of the n-type aluminum gallium nitride layer away from the sapphire substrate, wherein the second direction is perpendicular to the first direction; a metal platinum transparent electrode arranged on a side of the aluminum nitride layer away from the sapphire substrate; and a second metal contact layer arranged on a side of the metal platinum transparent electrode away from the sapphire substrate.

[0005] CN118507579A discloses an aluminum nitride vacuum detector based on a Schottky structure, which includes, from bottom to top, a substrate, an AlN buffer layer, an AlN epitaxial layer, an n-AlGaN layer, an AlN layer and a transparent electrode layer; a table top of the n-AlGaN layer is exposed on one side of the AlN layer and the transparent electrode layer, a first metal electrode is arranged on the table top, and the first metal electrode forms an ohmic contact with the n-AlGaN layer; an insulating film is arranged on the side of the AlN layer and the transparent electrode layer exposed on the table top, and a second metal electrode is arranged on the transparent electrode layer to form a Schottky structure.

[0006] The photosensitive layer thickness of the detector described in the above scheme is relatively large, and defects also increase accordingly, resulting in a longer carrier migration time, thereby limiting the response speed of the detector. Summary of the invention

[0007] The purpose of the present invention is to provide an ultraviolet absorption enhanced semiconductor film and its preparation method and application. The ultraviolet absorption enhanced semiconductor film of the present invention can make the surface reflection of the ultraviolet absorption enhanced semiconductor film with a thickness of several nanometers approach zero by utilizing the combined effect of interface phase shift and absorption phase shift, thereby increasing the light absorption of the semiconductor layer. While ensuring that the thickness of the ultraviolet absorption enhanced semiconductor film is small, the light absorption intensity is enhanced, thereby improving the response speed of the photodetector.

[0008] In order to achieve the purpose of the invention, the present invention adopts the following technical solutions:

[0009] In a first aspect, the present invention provides a semiconductor film with enhanced ultraviolet absorption, comprising a substrate and an aluminum intermediate layer and an aluminum nitride dielectric layer sequentially stacked on a surface of one side of the substrate.

[0010] The ultraviolet absorption enhanced semiconductor film of the present invention is I1M1M sub Structure, where I1 represents the upper high absorption dielectric layer semiconductor film, i.e., aluminum nitride dielectric layer, M1 represents the aluminum intermediate metal layer, i.e., metal Al, and M sub The structure design of the ultraviolet absorption enhanced semiconductor film is simple and effective, which is different from the traditional dielectric coating that relies on Fabry-Perot interference through a transparent layer with a thickness on the order of the wavelength to reduce reflection or enhance absorption. When ultraviolet light is irradiated onto the ultraviolet absorption enhanced semiconductor film of the present invention, the plasmon effect of the metal layer will produce a strong local electromagnetic field enhancement effect on the metal surface, which makes the incident light interact with the free electrons on the metal surface, thereby enhancing the absorption of light. At the same time, since the thickness of the AlN film is only a few nanometers, the number of vertical defects is much less than that of the thicker photosensitive layer, and the migration time of carriers in the direction perpendicular to the film plane is very short, which helps to quickly transport the photogenerated carriers to the external circuit and improve the response speed of the detector.

[0011] Preferably, the thickness of the aluminum nitride dielectric layer is 3 nm to 10 nm, for example, 3 nm, 5 nm, 8 nm, 9 nm or 10 nm, etc., and is not limited to the listed values, and other values ​​not listed within the numerical range are also applicable.

[0012] Preferably, the substrate comprises a sapphire substrate.

[0013] Preferably, the thickness of the substrate is 400 μm to 500 μm, for example, 400 μm, 420 μm, 450 μm, 480 μm or 500 μm, etc., but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0014] Preferably, the thickness of the aluminum intermediate layer is 100 nm to 150 nm, for example, 100 nm, 110 nm, 120 nm, 130 nm, 140 nm or 150 nm, etc., and is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0015] In a second aspect, the present invention provides a method for preparing the ultraviolet absorption enhanced semiconductor film as described in the first aspect, the preparation method comprising the following steps:

[0016] (1) depositing a first aluminum source on a substrate by molecular beam epitaxy to form an aluminum intermediate layer to obtain a semi-finished film;

[0017] (2) The semi-finished film is transferred to a plasma enhanced atomic layer deposition system, the second aluminum source is brought into the plasma enhanced atomic layer deposition system through a carrier gas, and plasma nitrogen is introduced into the plasma enhanced atomic layer deposition system. The plasma nitrogen reacts with the second aluminum source chemically adsorbed on the surface of the aluminum intermediate layer of the semi-finished film to undergo a nitridation reaction, and aluminum nitride is deposited on the aluminum intermediate layer of the semi-finished film to form an aluminum nitride dielectric layer, thereby obtaining the ultraviolet absorption enhanced semiconductor film.

[0018] The vacuum interconnection system of the present invention utilizes ultra-high vacuum pipes to interconnect the molecular beam epitaxial deposition equipment and the plasma enhanced atomic layer deposition system, thereby solving the pollution problems such as dust, surface oxidation and adsorption that are difficult to solve in the traditional clean room mode.

[0019] Preferably, the first aluminum source in step (1) comprises high-purity aluminum, and the purity of the high-purity aluminum in the present invention is ≥99.9999%.

[0020] Preferably, the substrate is cooled before the molecular beam epitaxy in step (1).

[0021] Preferably, after the cooling treatment, the temperature of the substrate is 25°C~80°C, for example: 25°C, 30°C, 40°C, 50°C, 60°C, 70°C or 80°C, etc., not limited to the listed values, other unlisted values ​​within the numerical range are also applicable.

[0022] Preferably, the deposition rate of the molecular beam epitaxy in step (1) is 0.5 nm / s to 1.5 nm / s, for example, 0.5 nm / s, 0.8 nm / s, 1 nm / s, 1.2 nm / s or 1.5 nm / s, etc., and is not limited to the listed values, and other values ​​not listed within the numerical range are also applicable.

[0023] Preferably, the time of the molecular beam epitaxy in step (1) is 1 min to 3 min, for example, 1 min, 1.2 min, 1.5 min, 1.8 min, 2 min, 2.5 min or 3 min, etc., and is not limited to the listed values. Other values ​​not listed within the numerical range are also applicable.

[0024] Preferably, during the molecular beam epitaxy in step (1), the surface of the substrate to be evaporated is inverted and parallel to the evaporation source, and rotates at a speed of 4 turns / min to 6 turns / min, for example, 4 turns / min, 4.5 turns / min, 5 turns / min, 5.5 turns / min or 6 turns / min, etc., not limited to the listed values, and other values ​​not listed within the numerical range are also applicable.

[0025] The surface to be deposited of the substrate of the present invention is inverted and parallel to the deposition source, that is, the substrate is located above the deposition source, and the surface to be deposited is inverted, parallel and facing the deposition source for hollow deposition.

[0026] Preferably, after the aluminum intermediate layer is formed in step (1), the semi-finished film is transferred to a plasma enhanced atomic layer deposition system through vacuum interconnection to deposit aluminum nitride.

[0027] The present invention directly prepares nanomaterials in an ultra-high vacuum environment (close to the lunar environment) through vacuum interconnection to keep the intrinsic properties of the materials from being contaminated by the outside world. The present invention uses ultra-high vacuum pipes to connect various functional devices to each other, solving the pollution problems such as dust, surface oxidation and adsorption that are difficult to solve in the traditional clean room model (mainly solving the problem of surface oxidation and surface impurities causing high roughness).

[0028] Preferably, before the second aluminum source is brought into the plasma enhanced atomic layer deposition system via the carrier gas in step (2), the semi-finished film is subjected to a heating treatment.

[0029] Preferably, after the heating treatment, the temperature of the semi-finished film is 300°C~350°C, for example: 300°C, 310°C, 320°C, 330°C, 340°C or 350°C, etc., not limited to the listed values, other unlisted values ​​within the numerical range are also applicable.

[0030] Preferably, in step (2), the second aluminum source comprises trimethylaluminum.

[0031] Preferably, the carrier gas for the plasma enhanced atomic layer deposition in step (2) includes argon.

[0032] Preferably, the flow rate of the argon gas is 15 sccm to 20 sccm, for example, 15 sccm, 16 sccm, 17 sccm, 18 sccm, 19 sccm or 20 sccm, etc., and is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0033] Preferably, the flow rate of the plasma nitrogen gas in step (2) is 2 sccm to 8 sccm, for example, 2 sccm, 3 sccm, 4 sccm, 5 sccm, 6 sccm, 7 sccm or 8 sccm, etc., and is not limited to the listed values. Other values ​​not listed within the numerical range are also applicable.

[0034] Preferably, in step (2), while introducing plasma nitrogen into the plasma enhanced atomic layer deposition system, argon plasma and hydrogen plasma are also introduced.

[0035] Preferably, the flow rate of the argon plasma is 3 sccm to 5 sccm, for example, 3 sccm, 3.5 sccm, 4 sccm, 4.5 sccm or 5 sccm, etc., and is not limited to the listed values, and other values ​​not listed within the numerical range are also applicable.

[0036] Preferably, the flow rate of the hydrogen plasma is 15 sccm to 25 sccm, for example, 15 sccm, 18 sccm, 20 sccm, 22 sccm or 25 sccm, etc., and is not limited to the listed values, and other values ​​not listed within the numerical range are also applicable.

[0037] Preferably, the power of the plasma enhanced atomic layer deposition in step (2) is 250W~350W, for example: 250W, 280W, 300W, 320W or 350W, etc., not limited to the listed values, and other values ​​not listed within the numerical range are also applicable.

[0038] In a third aspect, the present invention provides a photodetector, wherein the photodetector comprises the ultraviolet absorption enhanced semiconductor film as described in the first aspect.

[0039] Compared with the prior art, the present invention has the following beneficial effects:

[0040] (1) The ultraviolet absorption enhanced semiconductor film of the present invention can utilize the combined effect of interface phase shift and absorption phase shift to make the surface reflection of the ultraviolet absorption enhanced semiconductor film with a thickness of several nanometers approach zero, thereby increasing the light absorption of the semiconductor layer. While ensuring that the thickness of the ultraviolet absorption enhanced semiconductor film is small, the light absorption intensity is enhanced, thereby improving the response speed of the photodetector.

[0041] (2) The ultraviolet absorption enhanced semiconductor thin film structure of the present invention also has good stability and reliability. Due to the high thermal conductivity and good chemical stability of the AlN material itself, this structure can maintain stable performance under harsh environmental conditions. This is very important for ultraviolet photodetectors in practical applications, because they need to work reliably in various extreme environments.

[0042] (3) The ultraviolet absorption enhanced semiconductor film of the present invention has a simple structure and an easy preparation process. It reduces costs while also providing a good selective absorption effect, thus avoiding the difficulties of complex film processing such as high processing difficulty and low error tolerance.

[0043] (4) The maximum light absorption rate of the ultraviolet absorption enhanced semiconductor film of the present invention can reach more than 49.5%. By adjusting the thickness of the aluminum nitride layer, the maximum light absorption rate of the ultraviolet absorption enhanced semiconductor film can reach 90%. BRIEF DESCRIPTION OF THE DRAWINGS

[0044] Figure 1 It is a schematic diagram of the structure of the ultraviolet absorption enhanced semiconductor film provided by an embodiment of the present invention, wherein 1 is a sapphire substrate, 2 is an aluminum intermediate layer, 3 is an aluminum nitride dielectric layer, and I, II, and III are parallel reflected lights generated when the absorption phase shift of the aluminum nitride dielectric layer and the interface phase shift are superimposed.

[0045] Figure 2 It is a reflection contrast curve diagram of the ultraviolet absorption enhanced semiconductor film obtained in Example 1 and Example 3-Example 7.

[0046] Figure 3 It is a comparison diagram of light absorption curves of ultraviolet absorption enhanced semiconductor films obtained in Example 2 and Comparative Examples 1 to 3.

[0047] Figure 4 It is a comparison chart of light absorption curves of ultraviolet absorption enhanced semiconductor films obtained in Example 3 and Comparative Examples 4 to 6. DETAILED DESCRIPTION

[0048] The technical solution of the present invention is further described below by specific implementation methods. It should be understood by those skilled in the art that the embodiments are only to help understand the present invention and should not be regarded as specific limitations of the present invention.

[0049] The purity of the high-purity aluminum used in the embodiments of the present invention and the comparative examples is 99.99999%

[0050] Example 1

[0051] This embodiment provides a semiconductor film with enhanced ultraviolet absorption. The schematic structural diagram of the semiconductor film with enhanced ultraviolet absorption is shown in FIG. Figure 1As shown, the ultraviolet absorption enhanced semiconductor film includes a sapphire substrate 1 with a thickness of 450 μm, and an aluminum intermediate layer 2 with a thickness of 120 nm and an aluminum nitride dielectric layer 3 with a thickness of 4 nm stacked in sequence on the surface of the sapphire substrate 1. The ultraviolet absorption enhanced semiconductor film is prepared by the following method:

[0052] (1) Using a substrate cooling system, the temperature of a 450 μm thick sapphire substrate was controlled at 60°C. Using molecular beam epitaxy, the sapphire substrate was inverted and perpendicular to the aluminum source and rotated at a speed of 5 revolutions / min. High-purity aluminum was controlled to be deposited at a speed of 1 nm / s for 2 minutes to form an aluminum intermediate layer with a thickness of 120 nm, thereby obtaining a semi-finished film.

[0053] (2) The semi-finished film is transferred to a plasma enhanced atomic layer deposition system through a vacuum interconnection system, the semi-finished film is heated to 300° C., trimethylaluminum is introduced into the plasma enhanced atomic layer deposition system using argon at a flow rate of 18 sccm as a carrier gas, nitrogen, argon and hydrogen are used to generate plasma nitrogen, plasma argon and plasma hydrogen, the plasma nitrogen, plasma argon and plasma hydrogen are introduced into the plasma enhanced atomic layer deposition system at flow rates of 5 sccm, 4 sccm and 20 sccm, respectively, and the reaction is carried out for 25 minutes at a power of 300 W to form an aluminum nitride dielectric layer with a thickness of 4 nm, thereby obtaining the ultraviolet absorption enhanced semiconductor film.

[0054] Example 2

[0055] This embodiment provides a semiconductor film with enhanced ultraviolet absorption. The schematic structural diagram of the semiconductor film with enhanced ultraviolet absorption is shown in FIG. Figure 1 As shown, the ultraviolet absorption enhanced semiconductor film includes a sapphire substrate 1 with a thickness of 400 μm, and an aluminum intermediate layer 2 with a thickness of 150 nm and an aluminum nitride dielectric layer 3 with a thickness of 3 nm which are sequentially stacked on the surface of the sapphire substrate 1. The ultraviolet absorption enhanced semiconductor film is prepared by the following method:

[0056] (1) Using a substrate cooling system, the temperature of a 400 μm thick sapphire substrate was controlled at 50°C. Using molecular beam epitaxy, the sapphire substrate was inverted and perpendicular to the aluminum source and rotated at a speed of 4 revolutions / min. High-purity aluminum was deposited at a speed of 0.5 nm / s for 5 min to form an aluminum intermediate layer with a thickness of 150 nm, thereby obtaining a semi-finished film.

[0057] (2) The semi-finished film is transferred to a plasma enhanced atomic layer deposition system through a vacuum interconnection system, the semi-finished film is heated to 320° C., trimethylaluminum is introduced into the plasma enhanced atomic layer deposition system using argon at a flow rate of 20 sccm as a carrier gas, nitrogen, argon and hydrogen are used to generate plasma nitrogen, plasma argon and plasma hydrogen, the plasma nitrogen, plasma argon and plasma hydrogen are introduced into the plasma enhanced atomic layer deposition system at flow rates of 8 sccm, 5 sccm and 25 sccm, respectively, and the reaction is carried out for 20 minutes at a power of 350 W to form an aluminum nitride dielectric layer with a thickness of 3 nm, thereby obtaining the ultraviolet absorption enhanced semiconductor film.

[0058] Example 3

[0059] This embodiment provides a semiconductor film with enhanced ultraviolet absorption. The schematic structural diagram of the semiconductor film with enhanced ultraviolet absorption is shown in FIG. Figure 1 As shown, the ultraviolet absorption enhanced semiconductor film includes a sapphire substrate 1 with a thickness of 500 μm, and an aluminum intermediate layer 2 with a thickness of 100 nm and an aluminum nitride dielectric layer 3 with a thickness of 10 nm which are sequentially stacked on the surface of the sapphire substrate 1. The ultraviolet absorption enhanced semiconductor film is prepared by the following method:

[0060] (1) Using a substrate cooling system, the temperature of a 500 μm thick sapphire substrate was controlled at 50°C. Using molecular beam epitaxy, the sapphire substrate was inverted and perpendicular to the aluminum source and rotated at a speed of 6 revolutions / min. High-purity aluminum was controlled to be deposited at a speed of 1 nm / s for 100 s to form an aluminum intermediate layer with a thickness of 100 nm, thereby obtaining a semi-finished film.

[0061] (2) The semi-finished film is transferred to a plasma enhanced atomic layer deposition system through a vacuum interconnection system, the semi-finished film is heated to 350° C., trimethylaluminum is introduced into the plasma enhanced atomic layer deposition system using argon at a flow rate of 15 sccm as a carrier gas, nitrogen, argon and hydrogen are used to generate plasma nitrogen, plasma argon and plasma hydrogen, the plasma nitrogen, plasma argon and plasma hydrogen are introduced into the plasma enhanced atomic layer deposition system at flow rates of 2 sccm, 3 sccm and 15 sccm, respectively, and the reaction is carried out for 60 minutes at a power of 250 W to form an aluminum nitride dielectric layer with a thickness of 10 nm, thereby obtaining the ultraviolet absorption enhanced semiconductor film.

[0062] Example 4

[0063] The only difference between this embodiment and Embodiment 1 is that the thickness of the aluminum nitride dielectric layer in the ultraviolet absorption enhanced semiconductor film is 1 nm, and other conditions and parameters are exactly the same as those in Embodiment 1 (the preparation parameters need to be appropriately adjusted according to the thickness of the aluminum nitride dielectric layer).

[0064] Example 5

[0065] The only difference between this embodiment and Embodiment 1 is that the thickness of the aluminum nitride dielectric layer in the ultraviolet absorption enhanced semiconductor film is 2 nm, and other conditions and parameters are exactly the same as those in Embodiment 1 (the preparation parameters need to be appropriately adjusted according to the thickness of the aluminum nitride dielectric layer).

[0066] Example 6

[0067] The only difference between this embodiment and embodiment 1 is that the thickness of the aluminum nitride dielectric layer in the ultraviolet absorption enhanced semiconductor film is 6 nm, and other conditions and parameters are exactly the same as those in embodiment 1 (the preparation parameters need to be appropriately adjusted according to the thickness of the aluminum nitride dielectric layer).

[0068] Example 7

[0069] The only difference between this embodiment and Embodiment 1 is that the thickness of the aluminum nitride dielectric layer in the ultraviolet absorption enhanced semiconductor film is 8 nm, and other conditions and parameters are exactly the same as those in Embodiment 1 (the preparation parameters need to be appropriately adjusted according to the thickness of the aluminum nitride dielectric layer).

[0070] Comparative Example 1

[0071] The only difference between this comparative example and Example 2 is that the aluminum intermediate layer is replaced with a silver intermediate layer, and the other conditions and parameters are exactly the same as those in Example 2 (the preparation parameters need to be appropriately adjusted according to the type of intermediate layer).

[0072] Comparative Example 2

[0073] The only difference between this comparative example and Example 2 is that the aluminum intermediate layer is replaced by a gold intermediate layer, and the other conditions and parameters are exactly the same as those in Example 2 (the preparation parameters need to be appropriately adjusted according to the type of the intermediate layer).

[0074] Comparative Example 3

[0075] The only difference between this comparative example and Example 2 is that the aluminum intermediate layer is replaced with an aluminum oxide intermediate layer, and the other conditions and parameters are exactly the same as those of Example 2 (the preparation parameters need to be appropriately adjusted according to the type of the intermediate layer).

[0076] Comparative Example 4

[0077] The only difference between this comparative example and Example 3 is that the aluminum intermediate layer is replaced with a silver intermediate layer, and the other conditions and parameters are exactly the same as those of Example 3 (the preparation parameters need to be appropriately adjusted according to the type of intermediate layer).

[0078] Comparative Example 5

[0079] The only difference between this comparative example and Example 3 is that the aluminum intermediate layer is replaced by a gold intermediate layer, and the other conditions and parameters are exactly the same as those of Example 3 (the preparation parameters need to be appropriately adjusted according to the type of the intermediate layer).

[0080] Comparative Example 6

[0081] The only difference between this comparative example and Example 3 is that the aluminum intermediate layer is replaced with an aluminum oxide intermediate layer, and the other conditions and parameters are exactly the same as those of Example 3 (the preparation parameters need to be appropriately adjusted according to the type of the intermediate layer).

[0082] Comparative Example 7

[0083] The only difference between this comparative example and Example 1 is that the vacuum interconnection system is not used, and the other conditions and parameters are exactly the same as those in Example 1.

[0084] Performance Test:

[0085] The semiconductor film was prepared by the embodiment and the comparative example, and the FDTD simulation calculation software was used because it can add a monitor to obtain the absorption rate of the AlN layer. Subsequent experimental data are expected to use a PerkinElmer Lambda950 UV-visible spectrophotometer for reflection and transmission tests to record the maximum light absorption rate of the semiconductor film. The test results are shown in Table 1:

[0086] Table 1

[0087]

[0088] It can be seen from Table 1 that from Examples 1-7, the maximum light absorption rate of the ultraviolet absorption enhanced semiconductor film of the present invention can reach more than 49.5%, and by adjusting the thickness of the aluminum nitride layer, the maximum light absorption rate of the ultraviolet absorption enhanced semiconductor film can reach 90%.

[0089] The reflection contrast curves of the ultraviolet absorption enhanced semiconductor films obtained in Examples 1, 3 to 7 are as follows: Figure 2 As shown, by comparing Example 1 and Example 3-Example 7, it can be obtained that with the increase of the thickness of the aluminum nitride dielectric layer on the aluminum intermediate layer, the absorption of the aluminum nitride dielectric layer first increases and then decreases. This is because the vector sum of the absorption phase shift and the interface phase shift in this structure causes the phase difference of the reflected light on the surface of the aluminum nitride dielectric layer to be not an odd multiple of π and cannot better capture the incident light.

[0090] The light absorption curve comparison of the ultraviolet absorption enhanced semiconductor film obtained in Example 2 and Comparative Examples 1 to 3 is shown in FIG. Figure 3 As shown, the light absorption curve comparison of the ultraviolet absorption enhanced semiconductor film obtained in Example 3 and Comparative Examples 4 to 6 is shown in FIG. Figure 4As shown, by comparing Example 2 with Comparative Examples 1-3, and Example 3 with Comparative Examples 4-6, it can be seen that the reflection of the aluminum nitride dielectric layer on metal Au, Ag, and Al is very small, so a monitor is added between the aluminum nitride dielectric layer and the substrate to obtain the transmission T, and the absorption of the aluminum nitride dielectric layer is obtained by A=1-RT. As shown in the figure, it can be found that the 3nm aluminum nitride dielectric layer will enhance absorption on the metal, and the absorption is the largest on the aluminum intermediate layer, achieving nearly 86% absorption under 157nm incident light irradiation, and the ultraviolet absorption enhanced semiconductor film of the 10nm aluminum nitride dielectric layer achieves nearly 86% absorption at 196nm. The reason may be the surface plasmon effect of the aluminum intermediate layer, that is, when the incident light frequency matches the free electron vibration frequency of the Al metal surface, a strong local electromagnetic field enhancement effect will be generated, and the plasmon resonance wavelengths of Au and Ag are usually in the visible to infrared band.

[0091] The applicant declares that the above is only a specific implementation mode of the present invention, but the protection scope of the present invention is not limited thereto. Those skilled in the art should understand that any changes or substitutions that can be easily thought of by those skilled in the art within the technical scope disclosed by the present invention shall fall within the protection scope and disclosure scope of the present invention.

Claims

1. A semiconductor film with enhanced ultraviolet absorption, characterized in that: The ultraviolet absorption enhanced semiconductor film comprises a substrate and an aluminum intermediate layer and an aluminum nitride dielectric layer which are sequentially stacked on a surface of one side of the substrate.

2. The ultraviolet absorption enhanced semiconductor film according to claim 1, characterized in that: The thickness of the aluminum nitride dielectric layer is 3nm-10nm.

3. The ultraviolet absorption enhanced semiconductor film according to claim 1, characterized in that: The substrate includes a sapphire substrate.

4. The ultraviolet absorption enhanced semiconductor film according to claim 1, characterized in that: The thickness of the substrate is 400 μm-500 μm.

5. The ultraviolet absorption enhanced semiconductor film according to claim 1, characterized in that: The thickness of the aluminum intermediate layer is 100nm-150nm.

6. A method for preparing a semiconductor film with enhanced ultraviolet absorption as claimed in any one of claims 1 to 5, characterized in that: The preparation method comprises the following steps: (1) depositing a first aluminum source on a substrate by molecular beam epitaxy to form an aluminum intermediate layer to obtain a semi-finished film; (2) The semi-finished film is transferred to a plasma enhanced atomic layer deposition system, the second aluminum source is brought into the plasma enhanced atomic layer deposition system through a carrier gas, and plasma nitrogen is introduced into the plasma enhanced atomic layer deposition system. The plasma nitrogen reacts with the second aluminum source chemically adsorbed on the surface of the aluminum intermediate layer of the semi-finished film to undergo a nitridation reaction, and aluminum nitride is deposited on the aluminum intermediate layer of the semi-finished film to form an aluminum nitride dielectric layer, thereby obtaining the ultraviolet absorption enhanced semiconductor film.

7. The preparation method according to claim 6, characterized in that: Step (1) The first aluminum source includes high-purity aluminum; and / or, the substrate is subjected to a cooling treatment before the molecular beam epitaxy in step (1); And / or, after the cooling treatment, the temperature of the substrate is 25° C. to 80° C.; And / or, the deposition rate of the molecular beam epitaxy in step (1) is 0.5 nm / s to 1.5 nm / s; And / or, the time of the molecular beam epitaxy in step (1) is 1 min to 3 min; And / or, during the molecular beam epitaxy process of step (1), the surface of the substrate to be evaporated is inverted and parallel to the evaporation source, and rotates at a speed of 4 turns / min to 6 turns / min.

8. The preparation method according to claim 6, characterized in that: Step (2) transfers the semi-finished film to a plasma enhanced atomic layer deposition system through a vacuum interconnect to deposit aluminum nitride.

9. The preparation method according to claim 6, characterized in that: In step (2), before the second aluminum source is brought into the plasma enhanced atomic layer deposition system via the carrier gas, the semi-finished film is subjected to a heating treatment; and / or, after the heating treatment, the temperature of the semi-finished film is 300° C. to 350° C.; And / or, in step (2), the second aluminum source includes trimethylaluminum; and / or, the carrier gas for the plasma enhanced atomic layer deposition in step (2) comprises argon; And / or, the flow rate of the argon gas is 15 sccm to 20 sccm; And / or, the flow rate of the plasma nitrogen in step (2) is 2 sccm to 8 sccm; And / or, in step (2), while introducing plasma nitrogen into the plasma enhanced atomic layer deposition system, argon plasma and hydrogen plasma are also introduced; And / or, the flow rate of the argon plasma is 3 sccm to 5 sccm; And / or, the flow rate of the hydrogen plasma is 15 sccm to 25 sccm; And / or, the power of the plasma enhanced atomic layer deposition in step (2) is 250W~350W.

10. A photoelectric detector, characterized in that: The photodetector comprises the ultraviolet absorption enhanced semiconductor film as described in any one of claims 1-5.

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