Duvsensor based on ga2o3 heterojunction and method of manufacturing thereof

Abstract

A gallium oxide heterojunction-based DUV sensor includes an n-type gallium oxide substrate, an n-type gallium oxide epitaxial layer epitaxially grown on the n-type gallium oxide substrate, a p-type nickel oxide layer formed on the n-type gallium oxide epitaxial layer and forming a pn heterojunction with the n-type gallium oxide epitaxial layer, a patterned top electrode formed on the p-type nickel oxide layer, and a bottom electrode formed below the n-type gallium oxide substrate.

Description

[0001] Cross-reference to related applications This application claims priority to Korean Application No. 10-2024-0191777, filed on December 19, 2024, with the Korean Intellectual Property Office under 35 U.SC §119(a), the entire contents of which are incorporated herein by reference. Background Technology

[0002] This invention relates to a heterojunction-based DUV (deep UV) sensor.

[0003] UV sensors used in fire detectors include UVtrons that use vacuum tubes and semiconductor photodiodes that use wide-bandgap (WBG) materials such as SiC and GaN. However, currently used UV sensors do not possess the characteristics required for arc fire detection.

[0004] Arc fire detectors are primarily used to monitor areas of electrical distribution panels or equipment. These detectors require a sensor with a short sensing distance but capable of accurately detecting the wavelength range of the arc. Arcs are known to produce deep-ultraviolet (DUV) light in the 280nm to 200nm wavelength range. Although WBG-based UV photodiodes are more suitable for arc fire detectors than UVtrons, their application is difficult due to noise issues such as low output current and their responsiveness to UV-A and UV-B. Furthermore, WBG-based UV photodiodes are approximately 20 times more expensive than existing vacuum tube-based UVtrons, further complicating their application in fire detectors. Summary of the Invention

[0005] According to one aspect of the present invention, a gallium oxide heterojunction-based DUV sensor is provided, comprising: an n-type gallium oxide substrate; an n-type gallium oxide epitaxial layer disposed on the n-type gallium oxide substrate; a p-type nickel oxide layer disposed on the n-type gallium oxide epitaxial layer and configured to form a pn heterojunction with the n-type gallium oxide epitaxial layer; a patterned top electrode disposed on the p-type nickel oxide layer; and a bottom electrode disposed on the bottom surface of the n-type gallium oxide substrate.

[0006] In one embodiment, the patterned top electrode may include a plurality of coaxial ring regions sharing a common central axis; a connection region extending from the innermost coaxial ring region to the outermost coaxial ring region and electrically connected to each of the plurality of coaxial ring regions; and a pad region connected to the distal end of the connection region, the distal end being furthest from the common central axis.

[0007] In one embodiment, the patterned top electrode may include a nickel-chromium alloy layer disposed on a p-type nickel oxide layer and configured to form an ohmic contact with the p-type nickel oxide layer; and an aluminum-silicon alloy layer disposed on the nickel-chromium alloy layer.

[0008] In one embodiment, the aluminum-silicon alloy layer may have an aluminum to silicon weight ratio of 99:1.

[0009] In one embodiment, the patterned top electrode may include a p-type contact resistance reduction layer disposed on a p-type nickel oxide layer and configured to reduce contact resistance; a nickel-chromium alloy layer disposed on the contact resistance reduction layer; and an aluminum-silicon alloy layer disposed on the nickel-chromium alloy layer.

[0010] In one embodiment, the p-type contact resistance reduction layer may include a Li-doped nickel oxide layer with a carrier concentration greater than that of a p-type nickel oxide layer.

[0011] In one implementation, the thickness of the p-type contact resistance reduction layer can be less than the thickness of the nickel-chromium alloy layer.

[0012] In one embodiment, the aluminum-silicon alloy layer may have an aluminum to silicon weight ratio of 99:1.

[0013] In one embodiment, the bottom electrode may include a titanium layer disposed on the bottom surface of an n-type gallium oxide substrate and configured to form an ohmic contact; and an aluminum-silicon alloy layer disposed on the titanium layer.

[0014] According to another aspect of the present invention, a method for manufacturing a DUV sensor based on a gallium oxide heterojunction is provided, the method comprising: providing an n-type gallium oxide substrate on which an n-type gallium oxide epitaxial layer is formed; forming a bottom electrode on the bottom surface of the n-type gallium oxide substrate; forming a p-type nickel oxide layer on the n-type gallium oxide epitaxial layer; and forming a patterned top electrode on the p-type nickel oxide layer.

[0015] In one embodiment, forming a patterned top electrode on a p-type nickel oxide layer may include: forming a top electrode pattern on the p-type nickel oxide layer, the top electrode pattern including a plurality of coaxial ring regions, connection regions connected to the plurality of coaxial ring regions, and pad regions connected to the connection regions; depositing a nickel-chromium alloy layer on the p-type nickel oxide layer by sputtering using a nickel-chromium alloy target; depositing an aluminum-silicon alloy layer on the nickel-chromium alloy layer by sputtering using an aluminum-silicon alloy target; and removing the top electrode pattern.

[0016] In one embodiment, forming a patterned top electrode on a p-type nickel oxide layer may include: forming a top electrode pattern on the p-type nickel oxide layer, the top electrode pattern including a plurality of coaxial ring regions, connection regions connected to the plurality of coaxial ring regions, and pad regions connected to the connection regions; depositing a p-type Li-doped nickel oxide layer on the p-type nickel oxide layer by sputtering using a Li-doped nickel oxide target; depositing a NiCr alloy layer on the p-type Li-doped nickel oxide layer by sputtering using a NiCr alloy target; depositing an Aluminum-Silicon alloy layer on the NiCr alloy layer by sputtering using an Aluminum-Silicon alloy target; and removing the top electrode pattern. Attached Figure Description

[0017] In the following description, embodiments of the invention will be described with reference to the accompanying drawings. For ease of understanding, the same elements will be designated by the same reference numerals. The configurations shown in the drawings are examples for describing the invention and do not limit the scope of the invention. In particular, some elements are slightly enlarged in the drawings for ease of understanding. Since the drawings are intended for easy understanding of the invention, it should be noted that the width, depth, etc., of the elements shown in the drawings may vary in actual implementation. Furthermore, throughout the detailed description of the invention, the same components are described with reference to the same reference numerals.

[0018] Figure 1 An implementation scheme of a DUV sensor based on a gallium oxide heterojunction is shown; Figure 2 It shows along Figure 1 A cross-section of an embodiment of an AA'-based gallium oxide heterojunction DUV sensor; Figure 3 yes Figure 2 The image shows the IV characteristics of a gallium oxide heterojunction-based DUV sensor under dark conditions. Figure 4 It shows along Figure 1 A cross-section of an embodiment of an AA'-based gallium oxide heterojunction DUV sensor; Figure 5A , Figure 5B , Figure 5C , Figure 6A , Figure 6B , Figure 6C , Figure 7A and Figure 7B The fabrication process of a DUV sensor based on gallium oxide heterojunction is shown; Figure 8A and Figure 8B This shows measurements taken under dark conditions, such as... Figure 4 The graph shown represents the IV characteristics of the gallium oxide heterojunction-based DUV sensor. Figure 9A and Figure 9B This is a graph showing an exemplary photocurrent response of a gallium oxide heterojunction-based DUV sensor as a function of UV wavelength. Figure 10 This is a graph showing an exemplary responsivity of a gallium oxide heterojunction-based DUV sensor as a function of UV wavelength; Figure 11A and Figure 11B This is a graph showing the exemplary photocurrent characteristics of a gallium oxide heterojunction-based DUV sensor as a function of temperature. Figure 12 This is a graph showing the IV characteristics of a gallium oxide heterojunction-based DUV sensor under reverse bias conditions. Figure 13 This is a graph showing the current characteristics of a gallium oxide heterojunction-based DUV sensor as a function of the applied bias voltage. Figure 14 This is a graph showing the photocurrent characteristics of a gallium oxide heterojunction-based DUV sensor as a function of the distance between the sensor and the light source. Figure 15 This is a graph showing the photocurrent characteristics of a gallium oxide heterojunction-based DUV sensor as a function of the incident light wavelength. Detailed Implementation

[0019] The embodiments of the invention described in this specification with reference to the accompanying drawings can be implemented individually or in combination. However, these embodiments are provided for illustrative purposes only and are not intended to limit the scope of the invention. It should be understood that various modifications, substitutions, equivalents, and alterations can be made without departing from the concept and scope of the invention. Any function, feature, or embodiment disclosed in this specification can be implemented independently or in combination with other embodiments. Therefore, the scope of the invention is not limited to the specific embodiments shown in the accompanying drawings.

[0020] Terms such as “first” and “second” can be used to distinguish one element from another without implying any particular order, priority, or limitation.

[0021] The terminology used in the description of the embodiments is intended to describe specific examples only and is not intended to limit the invention. Unless otherwise expressly stated, singular expressions are intended to include plurals, and vice versa. Terms such as “comprising,” “including,” “having,” and variations thereof are intended to be inclusive and non-limiting, indicating the presence of said features, elements, steps, or components without excluding the possibility of additional or alternative features, elements, steps, or components.

[0022] When a component or layer is described as being “on,” “connected to,” or “coupled to” another component or layer, it can be located directly or indirectly on, connected to, or coupled to another component or layer, unless explicitly stated as “directly on,” “directly connected to,” or “directly coupled to,” in which case there is no intermediate component or layer.

[0023] For ease of description, spatial relative terms such as “above,” “below,” “upper,” “lower,” and similar expressions are used, referring to the relationships shown in the accompanying drawings. These terms are intended to cover different orientations of the apparatus or system during use, operation, or manufacture.

[0024] In the following detailed description, embodiments of the invention will be described in detail with reference to the accompanying drawings. Throughout the detailed description, the same or similar components are indicated by the same reference numerals.

[0025] Figure 1 An implementation scheme of a DUV sensor based on a gallium oxide heterojunction is shown.

[0026] The gallium oxide heterojunction-based DUV sensor 10 can detect DUV light and generate photocurrent. The upper surface of the gallium oxide heterojunction-based DUV sensor 10 is configured to receive incident DUV light. For example... Figure 2 and Figure 10 As shown, a patterned top electrode 140 can be formed on the p-NiO layer 130 to prevent interference from DUV incident on the p-NiO layer 130.

[0027] The patterned top electrode 140 can be formed from two or more vertically stacked layers to form a current path with the bottom electrode 120, such as... Figure 2 and Figure 4 As shown. This path outputs the photocurrent generated by the DUV incident on the sensor. The patterned top electrode 140 may include multiple coaxial ring regions 140C1 to 140C5 sharing a common central axis. The multiple coaxial ring regions 140C1 to 140C5 may be connected by connection regions 140L1 and 140L2. The connection regions 140L1 and 140L2 may extend from the innermost coaxial ring region 140C1 to the outermost coaxial ring region 140C5, connecting to all of the multiple coaxial ring regions 140C1 to 140C5, but may not be formed inside the innermost coaxial ring region 140C1. The pad region 140P is connected to the end of the connection regions 140L1 and 140L2 away from the common central axis.

[0028] The pad region 140P can be formed as a square region a × a, where a can be approximately 150 μm. The inner diameter b of the first coaxial ring region 140C1, located at the innermost of the plurality of coaxial ring regions 140C1 to 140C5, can be approximately 250 μm. The distance c between two adjacent coaxial ring regions 140C1 to 140C5 can be half the inner diameter b. Meanwhile, the width d of the plurality of coaxial ring regions 140C1 to 140C5 and the connecting regions 140L1 and 140L2 can be substantially the same and can be approximately 25 μm.

[0029] The gallium oxide heterojunction-based DUV sensor 10 can be housed within the sensor package 20 and electrically connected to an output pin, for example, via wiring. One end of the wire can be connected to the pad region 140P of the patterned top electrode 140, and the other end can be connected to the output pin. The bottom electrode 120 can be electrically fixed to the sensor package 20 using solder, conductive paste, or silver sintering.

[0030] Figure 2 It shows along Figure 1 A cross-section of one embodiment of the AA'-based gallium oxide heterojunction DUV sensor.

[0031] Reference Figure 2 The gallium oxide heterojunction-based DUV sensor 10 may include an n-type gallium oxide substrate 100, an n-type gallium oxide epitaxial layer 110, a bottom electrode 120, a p-type nickel oxide (p-NiO) layer 130, and a patterned top electrode 140. For the fabrication process of the gallium oxide heterojunction-based DUV sensor 10, refer to Figures 5 and 6.

[0032] The n-type gallium oxide substrate 100 can be formed of gallium oxide (β-Ga₂O₃) doped with an n-type dopant. The n-type dopant can be, for example, Sn or Si, and the carrier concentration of the n-type gallium oxide substrate 100 can be approximately 4.0 × 10⁻⁶. 18 cm -3 Meanwhile, the thickness of the n-type gallium oxide substrate 100 can be approximately 650 μm.

[0033] The n-type gallium oxide epitaxial layer 110 is formed by absorbing the photocurrent generated by DUV. It also forms a pn heterojunction with the p-type nickel oxide layer 130. The n-type gallium oxide epitaxial layer 110 can be formed by epitaxially growing a gallium oxide layer doped on an n-type gallium oxide substrate 100. The n-type dopant can be, for example, Si, and the carrier concentration of the n-type gallium oxide epitaxial layer 110 can be approximately 1.0 × 10⁻⁶. 16 cm -3 The thickness of the gallium oxide epitaxial layer 110 can be approximately 5.0 μm. The n-type gallium oxide epitaxial layer 110 can be deposited by, for example, HVPE (halide vapor phase epitaxy), MOCVD (metal-organic chemical vapor deposition), Mist CVD, MBE (molecular beam epitaxy), or PLD (pulsed laser deposition).

[0034] The bottom electrode 120 may include two or more metal layers sequentially stacked on the bottom surface of the n-type gallium oxide substrate 100. In one embodiment, the bottom electrode 120 may include a titanium layer 120a with a thickness of about 150 nm deposited on the bottom surface of the n-type gallium oxide substrate 100 to form an ohmic contact, and an aluminum-silicon alloy layer 120b with a thickness of about 400 nm may be deposited on the titanium layer 120a. The aluminum-silicon alloy layer 120b exhibits improved oxidation resistance compared to a pure aluminum layer and can be bonded to the sensor package 20 via soldering, conductive paste, or silver sintering.

[0035] A p-type nickel oxide layer 130 can be deposited on an n-type gallium oxide epitaxial layer 110 using a nickel oxide target, thereby forming a pn heterojunction. The p-type nickel oxide layer 130 can have a thickness of approximately 20 nm and a diameter of approximately 1.0 × 10⁻⁶ nm. 19 cm -3 The carrier concentration.

[0036] The patterned top electrode 140 may include multiple coaxial ring regions 140C1 to 140C5, connection regions 140L1, 140L2, and pad region 140P, which are formed by stacking two or more metal layers on the p-type nickel oxide layer 130. In one embodiment, the patterned top electrode 140 may include a nickel-chromium alloy layer 140a with a thickness of about 200 nm deposited on the p-type nickel oxide layer 130 to form an ohmic contact with the p-type nickel oxide layer 130, and an aluminum-silicon alloy layer 140b with a thickness of about 600 nm deposited on the nickel-chromium alloy layer 140a.

[0037] Figure 3 yes Figure 2 The diagram shows the IV characteristics of a gallium oxide heterojunction-based DUV sensor under dark conditions.

[0038] As shown in the IV characteristic plot on a logarithmic scale, when a voltage of approximately -6V to +6V is applied to it in the dark, the gallium oxide heterojunction-based DUV sensor 10 exhibits the rectification characteristics of a pn heterojunction diode.

[0039] Figure 4 It shows along Figure 1 A cross-section of one embodiment of the AA'-based gallium oxide heterojunction DUV sensor.

[0040] Reference Figure 4 The DUV sensor 11 based on gallium oxide heterojunction may include an n-type gallium oxide substrate 100, an n-type gallium oxide epitaxial layer 110, a bottom electrode 120, a p-type nickel oxide layer 130, and a patterned top electrode 140.

[0041] The n-type gallium oxide substrate 100 can be formed of gallium oxide (β-Ga₂O₃) doped with an n-type dopant. The n-type dopant can be, for example, Sn or Si, and the carrier concentration of the n-type gallium oxide substrate 100 can be approximately 4.0 × 10⁻⁶. 18 cm -3 Meanwhile, the thickness of the n-type gallium oxide substrate 100 can be approximately 650 μm.

[0042] The n-type gallium oxide epitaxial layer 110 is formed by absorbing the photocurrent generated by DUV. It also forms a pn heterojunction with the p-type nickel oxide layer 130. The n-type gallium oxide epitaxial layer 110 can be formed by epitaxially growing a gallium oxide layer doped on an n-type gallium oxide substrate 100. The n-type dopant can be, for example, Si, and the carrier concentration of the n-type gallium oxide epitaxial layer 110 can be approximately 1.0 × 10⁻⁶. 16 cm -3 The thickness of the gallium oxide epitaxial layer 110 can be approximately 5.0 μm. The n-type gallium oxide epitaxial layer 110 can be deposited by, for example, HVPE (halide vapor phase epitaxy), MOCVD (metal-organic chemical vapor deposition), Mist CVD, MBE (molecular beam epitaxy), or PLD (pulsed laser deposition).

[0043] The bottom electrode 120 may include two or more metal layers sequentially stacked on the bottom surface of the n-type gallium oxide substrate 100. In one embodiment, the bottom electrode 120 may include a titanium layer 120a with a thickness of about 150 nm deposited on the bottom surface of the n-type gallium oxide substrate 100 to form an ohmic contact, and an aluminum-silicon alloy layer 120b with a thickness of about 400 nm may be deposited on the titanium layer 120a. The aluminum-silicon alloy layer 120b exhibits improved oxidation resistance compared to a pure aluminum layer and can be bonded to the sensor package 20 via soldering, conductive paste, or silver sintering.

[0044] A p-type nickel oxide layer 130 can be deposited on an n-type gallium oxide epitaxial layer 110 using a nickel oxide target, thereby forming a pn heterojunction. The p-type nickel oxide layer 130 can have a thickness of approximately 20 nm and a diameter of approximately 1.0 × 10⁻⁶ nm. 19 cm -3 The carrier concentration.

[0045] The patterned top electrode 140 may include multiple coaxial ring regions 140C1 to 140C5, connection regions 140L1, 140L2, and pad region 140P, which are formed by stacking two or more metal layers on the p-type nickel oxide layer 130. The patterned top electrode 140 may further include a contact resistance reduction layer with a relatively high dopant concentration between the p-type nickel oxide layer 130 and the nickel-chromium alloy layer 140a to reduce contact resistance. In one embodiment, the patterned top electrode 140 may include a p+ type Li-doped nickel oxide layer 140c with a thickness of about 150 nm deposited on the p-type nickel oxide layer 130, a nickel-chromium alloy layer 140a with a thickness of about 200 nm deposited on the p+ type Li-doped nickel oxide layer 140c to form an ohmic contact with the p+ type Li-doped nickel oxide layer 140c, and an aluminum-silicon alloy layer 140b with a thickness of about 600 nm deposited on the nickel-chromium alloy layer 140a.

[0046] Figures 5A to 7B The fabrication process of a DUV sensor based on a gallium oxide heterojunction is shown.

[0047] Reference Figure 5A After fabricating an n-type gallium oxide substrate 100 on which an n-type gallium oxide epitaxial layer 110 is formed, the substrate is cleaned to remove foreign matter. The n-type gallium oxide substrate 100 and the n-type gallium oxide epitaxial layer 110 can be formed from β-Ga₂O₃ doped with an n-type dopant. The n-type gallium oxide epitaxial layer 110 can be formed on the n-type gallium oxide substrate 100 by epitaxial growth. The thickness of the n-type gallium oxide substrate 100 is approximately 650 μm, and the carrier concentration can be approximately 4.0 × 10⁻⁶. 18 cm -3 Meanwhile, the thickness of the n-type gallium oxide epitaxial layer 110 can be approximately 5.0 μm, and its carrier concentration can be approximately 1.0 × 10⁻⁶. 16 cm -3 .

[0048] Organic contaminants can be removed from the surface of the n-type gallium oxide substrate 100 by ultrasonic treatment for approximately 5 minutes while immersing in acetone. Subsequently, residual organic contaminants and fine particles can be removed by ultrasonic treatment for approximately 5 minutes while immersing in isopropanol (IPA). The n-type gallium oxide substrate 100 can then be rinsed with distilled water to remove residual chemicals. Afterward, the n-type gallium oxide substrate 100 can be cleaned with buffered oxide etchant (BOE) followed by another rinse with distilled water. To further remove remaining organic contaminants, the substrate can be irradiated with ultraviolet C (UVC) for approximately 24 hours. Finally, the thin oxide film formed on the n-type gallium oxide epitaxial layer 110 can be removed by dry etching.

[0049] Reference Figure 5BA bottom electrode pattern PR1 for forming a bottom electrode 120 can be formed on the bottom surface of the n-type gallium oxide substrate 100. The bottom electrode pattern PR1 can define polishing lines, and the bottom electrode 120 can be formed in an area excluding the polishing lines defined by the pattern PR1. In one embodiment, the bottom electrode pattern PR1 can be formed by spin-coating a liquid photoresist onto the substrate, followed by a soft bake, exposure, and development process.

[0050] Reference Figure 5C Two or more metal layers can be continuously deposited on the bottom surface of an n-type gallium oxide substrate 100. A titanium layer 120a with a thickness of approximately 150 nm can be deposited on the bottom surface of the n-type gallium oxide substrate 100 via DC sputtering in an Ar atmosphere, and an aluminum-silicon alloy layer 120b with a thickness of approximately 400 nm can be deposited on the bottom surface of the n-type gallium oxide substrate 100. The aluminum-silicon alloy target can have a composition ratio of approximately 99 wt% aluminum and 1 wt% silicon. During the sputtering process, the base pressure can be approximately 3 × 10⁻⁶. -6 The working pressure can be about 5 millitor, the Ar flow rate can be about 20 sccm, and the temperature can be maintained at room temperature.

[0051] Reference Figure 6A The bottom electrode 120 can be formed by removing the bottom electrode pattern PR1. For example, the bottom electrode pattern PR1 can be removed by a stripping process, thereby eliminating the metal layer deposited on the bottom electrode pattern PR1 formed along the grinding line. After removing the pattern PR1, the n-type gallium oxide epitaxial layer 110 can be subjected to UVC irradiation to remove residual organic contaminants.

[0052] refer to Figure 6B A p-type nickel oxide layer 130 can be formed on the n-type gallium oxide epitaxial layer 110. The p-type nickel oxide layer 130 can have a thickness of about 20 nm and can be deposited by radio frequency (RF) sputtering using a nickel oxide target in an Ar-O2 mixed gas atmosphere. During the sputtering process, the base pressure can be about 3 × 10⁻⁶. -6 The working pressure can be about 5 millitor, the Ar flow rate can be about 20 sccm, the O2 flow rate can be about 4 sccm, and the temperature can be maintained at room temperature.

[0053] Reference Figure 6C A top electrode pattern PR2 for forming a patterned top electrode 140 can be formed on the p-type nickel oxide layer 130. The pattern PR2 can be formed by spin-coating a liquid photoresist, followed by soft baking, exposure, and etching processes. Through the exposure and etching processes, the photoresist corresponding to the coaxial ring regions 140C1 to 140C5, the connection regions 140L1 and 140L2, and the pad region 140P can be removed, thereby exposing the underlying p-type nickel oxide layer 130.

[0054] Reference Figure 7A Two or more metal layers can be continuously deposited on the p-type nickel oxide layer 130. When manufacturing... Figure 4 When using the gallium oxide heterojunction-based DUV sensor 11 shown, a p+ type Li-doped nickel oxide layer 140c with a thickness of approximately 150 nm can be deposited on the p-type nickel oxide layer 130 by RF sputtering using a Li-doped nickel oxide target in an Ar-O2 mixed gas atmosphere. During this sputtering process, the base pressure can be approximately 3 × 10⁻⁶. -6 The working pressure can be about 5 millitor, the argon flow rate can be about 20 sccm, the oxygen flow rate can be about 4 sccm, and the temperature can be maintained at room temperature.

[0055] A nickel-chromium alloy layer 140a with a thickness of approximately 200 nm can then be deposited on the Li-doped nickel oxide layer 140c by DC sputtering using a nickel-chromium target in an Ar atmosphere. Subsequently, an aluminum-silicon alloy layer 140b with a thickness of approximately 600 nm can be deposited on the nickel-chromium alloy layer 140a by DC sputtering using an aluminum-silicon alloy target in an Ar atmosphere. The nickel-chromium target may contain approximately 80 wt% nickel and 20 wt% chromium. The presence of chromium enhances adhesion to the underlying Li-doped nickel oxide layer 140c, thereby improving mechanical stability and reducing electrode delamination during subsequent processes such as wiring and device operation.

[0056] In one implementation, when manufacturing Figure 2 When using the gallium oxide heterojunction-based DUV sensor 10 shown, the formation of the p+ type Li-doped nickel oxide layer 140c can be omitted. In this case, a nickel-chromium alloy layer 140a with a thickness of approximately 200 nm can be deposited directly on the p-type nickel oxide layer 130 using a nickel-chromium target in an Ar atmosphere via DC sputtering. Subsequently, an aluminum-silicon alloy layer 140b with a thickness of approximately 600 nm can be deposited on the nickel-chromium alloy layer 140a using an aluminum-silicon alloy target in an Ar atmosphere via DC sputtering.

[0057] Reference Figure 7B The top electrode 140 can be formed by removing the top electrode pattern PR2. For example, the top electrode pattern PR2 can be removed by a stripping process, thereby eliminating the metal layer deposited in areas other than those corresponding to the coaxial ring regions 140C1 to 140C5, the connection regions 140L1 and 140L2, and the pad region 140P.

[0058] Figure 8A and Figure 8B This shows measurements taken under dark conditions, such as... Figure 4 The graph shown represents the IV characteristics of the gallium oxide heterojunction-based DUV sensor.

[0059] Reference Figure 8A and 8B , with linear scaling ( Figure 8A ) and logarithmic scale ( Figure 8B The diagram shows the IV characteristics of a gallium oxide heterojunction-based DUV sensor 11 measured under dark conditions with applied voltages from approximately -6V to +3V. These graphs confirm that the sensor exhibits rectification behavior characteristics of a pn heterojunction diode. In particular, when compared... Figure 8B and Figure 3 At this time, the slope of the IV curve increases significantly under forward bias conditions, indicating the effectiveness of the contact resistance reduction layer. It has a thickness of approximately 1E20cm. -3 A p+ type Li-doped nickel oxide layer 140c with a high hole concentration can be deposited on the p-type nickel oxide layer 130 and form an ohmic junction with the nickel-chromium alloy layer 140a. Compared with the conventional p-NiO / NiCr interface, this structure exhibits lower contact resistance. The reduced contact resistance contributes to enhanced photocurrent generation, which is beneficial for arc detection applications. Furthermore, the multilayer structure including both p-type nickel oxide and p+ type Li-doped nickel oxide layers improves reverse bias characteristics, including reduced leakage current and increased breakdown voltage.

[0060] Figure 9A and Figure 9B This is a graph showing an exemplary photocurrent response of a gallium oxide heterojunction-based DUV sensor as a function of UV wavelength.

[0061] Figure 9A This demonstrates the effect when using a wavelength of approximately 254 nm and approximately 1,000 μW / cm. 2 The photocurrent response of a gallium oxide heterojunction-based DUV sensor when illuminated by light of a certain intensity at regular time intervals. Figure 9B The photocurrent response of the same sensor is shown when it is illuminated with light of approximately 222 nm at regular time intervals. Under 254 nm DUV illumination, the measured photocurrent (i.e., conduction current) is approximately 5 × 10⁻⁶. -7 A to 7×10 -7 A, while the dark current (i.e., the cutoff current) is approximately 5 × 10⁻⁶. -11 A to 7×10 -11 A, producing approximately 7.1 × 10 3 Up to 1.4×10 4 The on-current to off-current ratio. Under 222nm DUV irradiation, the on-current is approximately 1.7 × 10⁻⁶. -6 Up to 2.0×10 -6 A, the cutoff current is approximately 1.0 × 10⁻⁶. -10 Up to 2.0×10 -10 A, producing approximately 8.5 × 10 3 Up to 1.1×10 4The ratio of on-current to off-current.

[0062] Figure 10 This is a graph showing an exemplary responsivity of a gallium oxide heterojunction-based DUV sensor as a function of UV wavelength.

[0063] Reference Figure 10 The graph shows that at approximately 1,000 μW / cm 2 The responsivity of a gallium oxide heterojunction-based DUV sensor under a bias voltage of approximately 5 V was measured when irradiated with UV light in the wavelength range of approximately 200 nm to 600 nm. Two DUV sensors were fabricated using p-type nickel oxide layers with thicknesses of approximately 20 nm and 50 nm, respectively. Both sensors generated photocurrents when irradiated with UV light in the range of approximately 250 nm to 350 nm, which partially overlaps with the DUV wavelength band. A dominant responsivity peak was observed at approximately 260 nm in both sensors. Additionally, a secondary peak was detected at approximately 290 nm in the sensor with the 20 nm thick p-type nickel oxide layer and at approximately 300 nm in the sensor with the 50 nm thick layer. These results indicate that both thicknesses produce excellent DUV responsivity. However, the sensor with the thinner p-type nickel oxide layer exhibits a secondary peak at a shorter wavelength, indicating enhanced spectral selectivity and relatively superior DUV responsivity.

[0064] Figure 11A and Figure 11B This is a graph showing the exemplary photocurrent characteristics of a gallium oxide heterojunction-based DUV sensor as a function of temperature.

[0065] Reference Figure 11A The graph shows the photocurrent (including on-state and off-state currents) of a gallium oxide heterojunction-based DUV sensor measured at a bias voltage of approximately 5V as the ambient temperature changes from approximately 30°C to 120°C. The intensity is approximately 1,000 μW / cm². 2 The ultraviolet light irradiation sensor. Although the magnitude of the photocurrent varies with temperature, it maintains a distinguishable on-current / off-current ratio throughout the entire range.

[0066] On the contrary, such as Figure 11B As shown, when the ambient temperature exceeds approximately 130°C under the same bias and irradiation conditions, the leakage current increases significantly. This leads to a significant decrease in the on-current / off-current ratio, indicating abnormal operation of the DUV sensor at elevated temperatures.

[0067] Figure 12 This is a graph showing the IV characteristics of a gallium oxide heterojunction-based DUV sensor under reverse bias conditions.

[0068] Reference Figure 12The leakage current of a gallium oxide heterojunction-based DUV sensor was measured under reverse bias conditions in the absence of light (i.e., in darkness). The leakage current was approximately less than 1 nA, and the breakdown voltage was greater than -200 V.

[0069] Figure 13 This is a graph showing the current characteristics of a gallium oxide heterojunction-based DUV sensor as a function of the applied bias voltage.

[0070] Reference Figure 13 At bias voltages of 0V and 5V, by approximately 1,000μW / cm 2 The photocurrent of a gallium oxide heterojunction-based DUV sensor was measured by irradiating it with light of approximately 254 nm at regular time intervals. Under 254 nm DUV irradiation, the measured on-state current of the sensor at a 0 V bias voltage was approximately 4.2 × 10⁻⁶. -7 A, while the on-state current increases to approximately 7.8 × 10⁻⁶ under a 5V bias voltage. -7 A. In the absence of light, the measured current is close to 0A in both cases. These results confirm that applying a positive bias voltage enhances the photocurrent and increases the on-current / off-current ratio, thereby improving the sensor's DUV detection performance. Figure 14 This is a graph showing the photocurrent characteristics of a gallium oxide heterojunction-based DUV sensor as a function of the distance between the sensor and the light source.

[0071] Reference Figure 14 By changing the sensor and the emission wavelength to approximately 254 nm and the intensity to approximately 1,000 μW / cm, 2 The photocurrent of a gallium oxide heterojunction-based DUV sensor was measured simultaneously with the distance between the sensor and the source of DUV radiation. A bias voltage of approximately 5V was applied during the measurement. As expected, the photocurrent decreased with increasing distance from the source, confirming the sensor's distance-dependent responsivity to DUV illumination.

[0072] Figure 15 This is a graph showing the photocurrent characteristics of a gallium oxide heterojunction-based DUV sensor as a function of the incident light wavelength.

[0073] Reference Figure 15 By placing a gallium oxide heterojunction-based DUV sensor within a sensor package 20, applying a bias voltage of approximately 5V, and then applying a bias voltage of approximately 1,000μW / cm at regular time intervals, the bias voltage is applied. 2The photocurrent of the sensor was measured by irradiating it with light at wavelengths of approximately 254 nm (DUV) and 400 nm (UVA). A comparison of the photocurrent responses revealed that the photocurrent generated under 254 nm DUV irradiation was approximately 100 times greater than that generated under 400 nm UVA irradiation. This result confirms the sensor's exceptionally high DUV and UVA (or UVB) suppression ratio, demonstrating its strong wavelength selectivity and suitability for DUV-specific detection applications.

[0074] The foregoing description of embodiments of the present invention is provided for illustrative purposes and is not intended to be exhaustive or to limit the invention to the precise forms disclosed. Those skilled in the art will understand that various modifications, additions, and substitutions are possible without departing from the spirit and scope of the invention.

[0075] Therefore, the scope of this invention should be defined by the appended claims and their equivalents, rather than by the foregoing detailed description. All modifications and variations falling within the meaning and scope of the equivalents of the claims are intended to be included therein.

Claims

1. A DUV sensor based on gallium oxide heterojunction, comprising: n-type gallium oxide substrate; An n-type gallium oxide epitaxial layer disposed on the n-type gallium oxide substrate; A p-type nickel oxide layer disposed on the n-type gallium oxide epitaxial layer and configured to form a pn heterojunction with the n-type gallium oxide epitaxial layer; A patterned top electrode disposed on the p-type nickel oxide layer; and The bottom electrode is disposed on the bottom surface of the n-type gallium oxide substrate.

2. The DUV sensor based on gallium oxide heterojunction according to claim 1, wherein, The patterned top electrode includes: Multiple coaxial ring areas sharing a common central axis; A connection region extending from the innermost coaxial ring region to the outermost coaxial ring region and electrically connected to each of the plurality of coaxial ring regions; and A pad area connected to the far end of the connection area, the far end being furthest from the common central axis.

3. The DUV sensor based on gallium oxide heterojunction according to claim 1, wherein, The patterned top electrode includes: A nickel-chromium alloy layer disposed on the p-type nickel oxide layer and configured to form an ohmic contact with the p-type nickel oxide layer; and An aluminum-silicon alloy layer is disposed on the nickel-chromium alloy layer.

4. The DUV sensor based on gallium oxide heterojunction according to claim 3, wherein, The aluminum-silicon alloy layer has an aluminum to silicon weight ratio of 99:

1.

5. The DUV sensor based on gallium oxide heterojunction according to claim 1, wherein, The patterned top electrode includes: A p-type contact resistance reduction layer disposed on the p-type nickel oxide layer and configured to reduce contact resistance; A nickel-chromium alloy layer disposed on the contact resistance reduction layer; and An aluminum-silicon alloy layer is disposed on the nickel-chromium alloy layer.

6. The gallium oxide heterojunction-based DUV sensor according to claim 5, wherein, The p-type contact resistance reduction layer includes a Li-doped nickel oxide layer with a carrier concentration greater than that of the p-type nickel oxide layer.

7. The gallium oxide heterojunction-based DUV sensor according to claim 5, wherein, The thickness of the p-type contact resistance reduction layer is less than the thickness of the nickel-chromium alloy layer.

8. The gallium oxide heterojunction-based DUV sensor according to claim 5, wherein, The aluminum-silicon alloy layer has an aluminum to silicon weight ratio of 99:

1.

9. The DUV sensor based on gallium oxide heterojunction according to claim 1, wherein, The bottom electrode includes: A titanium layer disposed on the bottom surface of the n-type gallium oxide substrate and configured to form an ohmic contact; and An aluminum-silicon alloy layer is disposed on the titanium layer.

10. A method for manufacturing a gallium oxide heterojunction-based DUV sensor, comprising: An n-type gallium oxide substrate on which an n-type gallium oxide epitaxial layer is formed; A bottom electrode is formed on the bottom surface of the n-type gallium oxide substrate; A p-type nickel oxide layer is formed on the n-type gallium oxide epitaxial layer; and A patterned top electrode is formed on the p-type nickel oxide layer.

11. The method according to claim 10, wherein, Forming the patterned top electrode on the p-type nickel oxide layer includes: A top electrode pattern is formed on the p-type nickel oxide layer. The top electrode pattern includes multiple coaxial ring regions, connection regions connected to the multiple coaxial ring regions, and pad regions connected to the connection regions. A nickel-chromium alloy layer is deposited on the p-type nickel oxide layer by sputtering using a nickel-chromium alloy target; An aluminum-silicon alloy layer is deposited on the nickel-chromium alloy layer by sputtering using an aluminum-silicon alloy target; and Remove the top electrode pattern.

12. The method according to claim 10, wherein, Forming the patterned top electrode on the p-type nickel oxide layer includes: A top electrode pattern is formed on the p-type nickel oxide layer. The top electrode pattern includes multiple coaxial ring regions, connection regions connected to the multiple coaxial ring regions, and pad regions connected to the connection regions. A p-type Li-doped nickel oxide layer was deposited on the p-type nickel oxide layer by sputtering using a Li-doped nickel oxide target. A nickel-chromium alloy layer was deposited on the p-type Li-doped nickel oxide layer by sputtering using a nickel-chromium alloy target. An aluminum-silicon alloy layer is deposited on the nickel-chromium alloy layer by sputtering using an aluminum-silicon alloy target; and Remove the top electrode pattern.

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