Methods for manufacturing UV radiation detector devices and UV radiation detector devices

Abstract

Embodiments of this disclosure relate to methods of manufacturing UV radiation detector devices and UV radiation detector devices themselves. The device for detecting UV radiation includes: an N-doped SiC substrate; an N-doped SiC drift layer extending over the substrate; a cathode terminal; and an anode terminal. The anode terminal includes: a P-doped doped anode region extending within the drift layer; and an ohmic contact region including one or more carbon-rich layers, particularly graphene and / or graphite layers, extending within the doped anode region. The ohmic contact region is transparent to the UV radiation to be detected.

Description

Technical Field

[0001] This disclosure relates to a method for manufacturing a UV radiation detector device and a UV radiation detector device. Specifically, this disclosure relates to a photodetector diode having an anode terminal or cathode terminal that is transparent to the UV radiation to be detected. Background Technology

[0002] As is well known, especially for power supply applications, it features a wide bandgap (particularly a bandgap energy value Eg higher than 1.1eV) and low on-resistance (Rg). ON Semiconductor materials with high thermal conductivity, high operating frequency, and high carrier saturation velocity are ideal for manufacturing electronic components such as diodes or transistors. Silicon carbide (SiC) is a material with these properties and designed for use in manufacturing electronic components. Specifically, in terms of the properties listed above, silicon carbide is preferred over silicon in its various polymorphs (e.g., 3C-SiC, 4H-SiC, 6H-SiC).

[0003] Electronic devices provided on silicon carbide substrates offer numerous advantages over similar devices provided on silicon substrates, such as low output on-resistance, low leakage current, high operating temperature, and high operating frequency. Specifically, the detection of ultraviolet (UV) radiation, such as from the sun, astronomical objects, or artificial light sources (in medical, military, environmental, and astronomical fields), has received considerable attention in recent years. Therefore, the fabrication of high-sensitivity diode arrays is of particular interest. In this context, wide-bandgap materials are excellent candidates for UV radiation detection; silicon carbide is therefore particularly suitable for this purpose. Among SiC polymorphs, 4H-SiC is more preferred for UV radiation detection due to its wide bandgap (approximately 3.3 eV).

[0004] Known types of Schottky or PN photodiodes for detecting UV radiation are fabricated on a 4H-SiC epitaxial layer grown on a heavily doped substrate. Schottky contacts are provided on the front side of the photodiode by forming a metal region to provide the Schottky contacts, while ohmic contacts are provided on the back side of the photodiode, for example, by forming a nickel layer followed by rapid thermal annealing (at approximately 950°C–1000°C). The Schottky contacts on the front side are obtained by defining a typically comb-shaped titanium or nickel silicide structure through a photolithography process. The geometry of the Schottky contacts on the front side (front electrode) is chosen to allow direct exposure to the radiation to be detected, thereby fabricating the vertical conductive electrical operation of the Schottky photodiode.

[0005] The area of ​​a single diode directly exposed to UV radiation and electro-optic activity is limited by the presence of a front Schottky contact, which reflects and / or absorbs UV radiation and thus reduces the useful area of ​​effective exposure.

[0006] Figure 1 A vertically conducting Schottky diode of a known type is shown in a side-view section in a Cartesian reference frame with X, Y, and Z axes (three axes).

[0007] Schottky diode 1 includes: N-type heavily doped SiC (e.g., 1.10). 20 atoms / cm 3 The substrate 3 is provided with a surface 3a opposite to the surface 3b; a SiC drift layer 2 epitaxially grown on the surface 3a of the substrate 3, the N-type doping concentration of which is lower than the doping concentration of the substrate 3; an ohmic contact region 6 (e.g., nickel silicide) extending above the surface 3b of the substrate 3; a cathode metallization 16 extending above the ohmic contact region 6; and an anode metallization 8 extending above the top surface 2a of the drift layer 2.

[0008] Schottky contacts or junctions (semiconductor metal type) are thus formed at the interface between the drift layer 2 and the anode metallization 8. Specifically, the Schottky junction is formed by the portion of the drift layer 2 that is in direct electrical contact with the corresponding portion of the anode metallization 8.

[0009] As mentioned above, a drawback of this device is the reduction of the active area, i.e., the region dedicated to charge carrier generation after interaction with the UV radiation to be detected. In fact, the portion of surface 2a coated with the anodic metallization 8 does not participate in the detection of UV radiation or the subsequent generation of charge carriers due to absorption and / or reflection of the UV radiation to be detected by the anodic metallization 8 itself. Summary of the Invention

[0010] The purpose of this invention is to provide a method for manufacturing a UV radiation detector device and a UV radiation detector device that can overcome the defects of the prior art.

[0011] According to this disclosure, a method for manufacturing a UV radiation detector device and a UV radiation detector device are provided. This disclosure includes a method for manufacturing a detector device for detecting UV radiation by: forming a drift layer of SiC having a first conductivity and a second concentration of dopant, the second concentration of dopant being lower than the first concentration, on the front side of a silicon carbide (SiC) substrate having a first conductivity and a first concentration of dopant; forming a cathode terminal of the detector device on the back side of the substrate; and forming an anode terminal of the detector device in the drift layer. Forming the anode terminal includes forming a doped anode region by implanting a dopant having a second conductivity opposite to the first conductivity into the drift layer, and forming a first ohmic contact region includes forming one or more carbon-rich layers in the doped anode region using a laser.

[0012] This disclosure also includes: a device having a silicon carbide substrate having a first doping type with a first doping concentration, the silicon carbide substrate including a first surface opposite to a second surface; a drift layer located on the first surface of the silicon carbide substrate, the drift layer having a first doping type and having a first surface spaced apart from the first surface of the silicon carbide substrate; an anode having a second doping type in the drift layer between the first surface of the drift layer and the first surface of the silicon carbide substrate; and a first ohmic contact in the anode between the first surface of the drift layer and the first surface of the silicon carbide substrate, the first ohmic contact comprising carbon. Attached Figure Description

[0013] To better understand this disclosure, preferred embodiments thereof will now be described by way of non-limiting example only, with reference to the accompanying drawings, in which:

[0014] Figure 1 This is a cross-sectional view of a Schottky photodiode according to a known embodiment;

[0015] Figure 2 This is a cross-sectional view of a UV radiation detector device according to an embodiment of the present disclosure;

[0016] Figures 3-5 An embodiment of the present disclosure is shown for manufacturing. Figure 2 The steps of the device;

[0017] Figure 6 The figure illustrates a measurement of the transmittance of a device manufactured according to this disclosure; and

[0018] Figure 7 This is a cross-sectional view of a UV radiation detector device according to another embodiment of the present disclosure. Detailed Implementation

[0019] Figure 2 A device 50 according to one aspect of this disclosure, particularly a device for detecting ultraviolet radiation (UV), specifically a PN diode, is shown in a side-view sectional view in a (triaxial) Cartesian reference frame of axes X, Y, and Z. In this context, device 50 is designed to detect radiation in the wavelength range of 200 nm to 380 nm.

[0020] Device 50 includes: an N-type SiC substrate 53 having a first doping concentration, the N-type SiC substrate 53 being provided with a surface 53a opposite to surface 53b and having a thickness including between 50 μm and 350 μm, for example, a thickness substantially equal to 180 μm; an N-type SiC drift layer (e.g., epitaxially grown) 52 having a second doping concentration lower than the first doping concentration, extending above surface 53a of substrate 53 and having a thickness including between 5 μm and 10 μm. Thickness between 0 μm; Ohmic contact region or layer 56 (e.g., nickel silicide) extending over surface 53b of substrate 53; cathode metallization 57, such as Ti / NiV / Ag or Ti / NiV / Au, extending over ohmic contact region 56; P-type implanted anode region 59 extending in drift layer 52 facing top surface 52a of drift layer 52; and ohmic contact layer 60 extending in implanted anode region 59 and facing top surface 52a of drift layer 52.

[0021] The doping level of substrate 53 is, for example, included in 1.10. 19 Up to 1.10 22 atoms / cm 3 Between; the doping level of drift layer 52 is, for example, included in 1.10 13 Up to 5.10 16 atoms / cm 3 Between; the doping level of the implanted anode region 59 is, for example, equal to or greater than 1.10. 18 atoms / cm 3 .

[0022] According to one aspect of the invention, the ohmic contact layer 60 comprises one or more carbon-rich layers, which include, for example, a graphite layer or a graphene multilayer. More specifically, the ohmic contact layer 60 has a SiC amorphous layer on surface 52a, in which carbon atoms are predominantly present than silicon atoms (e.g., at least twice as many as silicon atoms, specifically two to 100 times) after phase separation between silicon and carbon atoms in the SiC substrate. Below this amorphous layer, the ohmic contact layer 60 may present a layer comprising carbon clusters (e.g., a graphite layer), the thickness of which is greater than the thickness of the amorphous layer. The formation of the ohmic contact layer 60 is due to the thermal decomposition of silicon carbide, as a result of the manufacturing process illustrated below.

[0023] According to another aspect of this disclosure, the ohmic contact layer 60 is self-aligned with the injection region 59 on the surface 52a (i.e., in a top view in the plane XY, the ohmic contact layer 60 has the same shape and extension as the injection region 59).

[0024] Additionally, according to another aspect of this disclosure, the ohmic contact layer 60 does not extend along the Z direction beyond the surface 52a; in other words, the ohmic contact layer 60 has a top surface 60a that is coplanar with the surface 52a (i.e., aligned along the X direction), and extends in the injection region 59 to a depth (along the Z direction) between 1 nanometer and tens of nanometers (e.g., between 1 and 20 nm) measured from the surface 52a.

[0025] During the design phase, the shape or “layout” of the injection region 59 (and therefore the ohmic contact layer 60) in a planar view in the XY plane can be selected as needed. Specifically, the injection region 59 may extend continuously over the entire active area of ​​the device 50 (in a top view in the XY plane), or extend only over a portion of the active area of ​​the device 50, or may be formed by multiple injection sub-regions spaced apart from each other by portions of the drift layer 52.

[0026] The applicant has discovered that the aforementioned type of ohmic contact layer 60 is transparent to UV radiation, particularly to radiation with wavelengths in the range of 200 nm to 380 nm. Therefore, in use, even when the ohmic contact layer 60 covers the entire active area of ​​the device 50, the UV radiation to be detected will in any case pass through the ohmic contact layer 60, reach the drift layer 52, and generate charge carriers in a manner known per se. By properly polarizing the device 50 between the anode and cathode (e.g., via bond wires), the current induced by UV radiation can be collected and measured in a manner known per se, which is not part of this disclosure.

[0027] The following description of the device 50 formation steps refers only to the formation steps of the ohmic contact layer 60 (the remaining steps are performed according to the prior art).

[0028] refer to Figure 3 A wafer 100, including a SiC substrate 53 (specifically, 4H-SiC; however, other polymorphs may be used, such as, but not exclusively, 2H-SiC, 3C-SiC and 6H-SiC), is arranged.

[0029] As described above, substrate 53 has a first conductivity type (N-type doped in this embodiment) and is provided with a front surface 53a and a rear surface 53b opposite to each other along the Z-axis. Substrate 53 has a 1.10 19 Up to 1.10 22 atoms / cm 3 The doping concentration between them.

[0030] The front side of wafer 100 corresponds to the front surface 53a, and the back side of wafer 100 corresponds to the rear surface 53b. The resistivity of substrate 30 is, for example, between 2 mΩ·cm and 40 mΩ·cm.

[0031] For example, a first conductivity type (N) and a doping concentration (e.g., included in 1.10) are formed on the front surface 53a of the substrate 53 by epitaxial growth. 13 Up to 5.10 16 atoms / cm 3 A silicon carbide drift layer 52 with a doping concentration lower than that of the substrate 53. The drift layer 52 is SiC, specifically 4H-SiC, but other SiC polymorphs such as 2H, 6H, 3C or 15R can also be used.

[0032] The drift layer 52 has a thickness defined between the top side 52a and the bottom side 52b (the latter being in direct contact with the front surface 53a of the substrate 53).

[0033] Then( Figure 4 Implantation is performed on doped material (e.g., boron or aluminum) having a second conductivity type (here, P conductivity type). As previously mentioned, implantation (indicated by arrow 72 in the figure) can be performed with or without an implantation mask, depending on design requirements. Without an implantation mask, as shown, the implantation region extends over the entire extent of the Cartesian reference plane XY of the drift layer 52 and extends to a certain depth along Z, which is related to the implantation energy itself; with an implantation mask, one or more implantation regions extend at locations where the implantation mask is transparent to the implantation.

[0034] In the embodiments provided by way of example Figure 4 The injection step includes a second conductivity type, with the injection energy ranging from 30 keV to 500 keV and the dose between 1.10. 12 atoms / cm 2 Up to 1.10 15 atoms / cm 2 One or more dopants are implanted between the dopants. Subsequent thermal annealing can activate the implanted dopants and form a doping concentration higher than 1.10. 18 atoms / cm 3 Furthermore, the depth of the injected anode region 59, measured from surface 52a, is between 0.3 μm and 1 μm.

[0035] Next ( Figure 5 A thermal budget is generated on surface 52a, which is designed to facilitate the generation of one or more carbon-rich layers (e.g., graphene and / or graphite layers) in injection region 59.

[0036] For this purpose, a laser source 80 is used, which is configured to generate a suitable beam 82.

[0037] Laser 80 is, for example, a UV excimer laser. Other types of lasers with wavelengths in the visible light region can also be used.

[0038] To achieve the purpose of this disclosure, namely, to enable the formation of an ohmic contact in the injection region 59, the configuration and operating parameters of the laser 80 are optimized as follows:

[0039] Wavelength: Between 290nm and 370nm, specifically 310nm;

[0040] Pulse duration: between 100ns and 300ns, specifically 160ns;

[0041] Pulse count (scan): Between 1 and 5;

[0042] Energy density: 1.5 J / cm³ 2 Up to 4J / cm 2 Between, specifically 3J / cm 2 (Considered at the level of surface 52a); and

[0043] Temperature: Between 1400℃ and 2600℃, specifically 1800℃ (considered at the level of surface 52a).

[0044] The spot area of ​​beam 82 at the level of surface 52a is, for example, included in 0.7 cm. 2 Up to 1.5cm 2 between.

[0045] In order to cover the entire wafer 100 or the sub-region to be heated in the wafer 100, one or more scans of the laser 80 are therefore performed in the plane XY (e.g., multiple scans that are parallel to each other and parallel to the X-axis and / or Y-axis).

[0046] Given the depth of the implantation region 59, a temperature of approximately 2000°C at the level of the surface 52a is sufficient to ensure that the temperature within the aforementioned range is also at the maximum depth reached by the implantation region 59 (e.g., 1 μm), thereby ensuring the activation of all dopants without the need for a dedicated thermal budget.

[0047] This temperature, for example, favors compounds that generate carbon-rich ohmic contacts only in the implantation region 59 and not on the surface 52a where there is no implantation region 59. This type of effect, known in itself, is described, for example, by Maxime G. Lemaitre, “Low-temperature, site selective graphitization of SiC via ion implantation and pulsed laser annealing”, APPLIED PHYSICS LETTERS 100, 193105 (2012).

[0048] In one embodiment, the transformation of a portion of the injection region 59 to the ohmic contact layer 60 is achieved by heating the entire wafer 100 and appropriately moving the laser 80. The energy density of the beam 82 is included in 1.5 J / cm². 2 Up to 3J / cm 2 In the case of local and surface temperature increases, the formation of the ohmic contact layer 60 occurs. This effect is not observed in the absence of the injection region 59.

[0049] In different embodiments, the transformation of the surface portion of the injection region 59 to the ohmic contact layer 60 is achieved by processing only a portion of the wafer 100, which may not correspond to the entire extension of the injection region 59 (e.g., excluding potentially uninteresting portions during the use of the device 50 as a UV detector, as long as they are not involved in charge generation and transport).

[0050] In another embodiment, a mask may be arranged on surface 52a (in contact with or at a distance from surface 52a), the mask having one or more regions transparent to the beam 82 (i.e., through which the beam 82 passes) and regions opaque to the beam 82 (i.e., through which the beam 82 does not pass, or passes through in a weakened manner, such as not heating portions of the wafer 100 extending beneath it). The transparent regions in the mask aligned with the injection region 59 (or the corresponding injection region) enable the formation of the corresponding ohmic contact layer 60. Drift layer 52, without possible P-injection regions, is covered and protected by the mask. In this case, the energy density of the beam 82 can be increased to 4.5 J / cm². 2 Or even higher. In fact, in order to generate ohmic contacts in the doped region during epitaxial growth, the energy density of the laser beam needs to be higher than that required for generating ohmic contacts in the doped region by means of an ion implantation process (specifically, higher than about 3 J / cm²). 2 ).

[0051] In this embodiment, because a mask is used to expose only the injection region 59, it is possible to use a power higher than 3 J / cm without the risk of forming ohmic contacts on the N-type region of the drift layer 52. 2 Energy density.

[0052] In one embodiment, the thermal annealing step for activating the dopant in the implantation region 59 can overlap with the step of forming the ohmic contact layer 60, provided that the temperature reached by the laser beam 82 is sufficient to activate the dopant. Alternatively, conventional thermal annealing can be performed prior to the formation of the ohmic contact layer 60 in any case.

[0053] The transition from p-type SiC to ohmic contacts occurs at temperatures ranging from 1200°C to 2600°C, more specifically above 1600°C. These temperatures are reached in the surface portion (a few nanometers, e.g., 1 nm–20 nm) of the implantation region 59.

[0054] For deeper depths, the temperature drops to a value that prevents silicon carbide from transforming into a carbon-rich layer (graphene and / or graphite layer).

[0055] The formation of the ohmic contact is therefore self-limiting. Thus, the ohmic contact layer 60 does not extend through the entire thickness of the corresponding injection region, but only extends horizontally at its surface. The ohmic contact layer 60 is formed within the injection region 59 such that the top surface of the injection region 59 is coplanar with or otherwise coincides with the top surface of the ohmic contact layer 60.

[0056] The applicant has discovered that, using the previously identified laser configuration and operating parameters, the desired electrical and optical behavior of device 50 was obtained. In this regard, Figure 6 The illustration shows experimental data on transmittance after the formation of the ohmic contact layer 60 and exposure of the device 50 to UV radiation of various wavelengths; the behavior is as expected and comparable to that of conventional UV detectors.

[0057] Figure 7 The illustration shows a UV detector device 150 according to another aspect of the present disclosure.

[0058] Device 150 and Figure 2 The common elements of the devices 50 are indicated by the same reference numerals and will not be described further.

[0059] Unlike device 50, device 150 does not have a nickel silicide ohmic contact layer 56 and a cathode metallization 57. Instead, device 150 includes an ohmic contact layer 156 extending over the surface 53b of substrate 53. The ohmic contact layer 156 is similar to ohmic contact layer 60 (specifically, it may include one or more carbon-rich layers, such as graphite layers or graphene multilayers) and is transparent to the UV radiation to be detected (e.g., wavelengths in the range of 200 nm to 380 nm).

[0060] Forming the ohmic contact layer 156 includes laser processing (similar to that previously discussed for the formation of the ohmic contact layer 60).

[0061] Optimizing the ohmic properties of the contact 156 on the back side of the substrate 53 (which is N-doped) requires a different energy density from that required to optimize the ohmic properties of the layer 60 in the implanted region (which is P-doped). Indeed, as described above, to generate an ohmic contact on an N-doped substrate, a laser beam energy density greater than that required to generate an ohmic contact in the doped region P via the implantation process is needed. Therefore, the operating parameters of the laser 80 can be adjusted to generate beams with different characteristics depending on whether the ohmic contact layer 60 or 156 is to be formed; each beam is designed to generate a corresponding layer with ohmic properties.

[0062] Therefore, an ohmic contact 156 can also be formed on the back side 53b of the substrate 53 using a laser 80 with the following configuration and operating parameters:

[0063] Wavelength: Between 290nm and 370nm, specifically 310nm;

[0064] Pulse duration: between 100ns and 300ns, specifically 160ns;

[0065] Pulse count (scan): Between 1 and 5;

[0066] Energy density: at 3 J / cm 2 Up to 4.5 J / cm 2 Between, specifically 3.2 J / cm 2 Up to 4.5 J / cm 2 Between; and

[0067] Temperature: Between 1400°C and 2600°C, specifically above 1800°C (considering the level of surface 53b).

[0068] In this way, a UV detector capable of receiving UV radiation from both sides (front and back) was obtained.

[0069] Upon examination of the features provided in this disclosure, the advantages offered are obvious.

[0070] Specifically, regardless of the presence of electrical contacts (as described above in this disclosure, electrical contacts are transparent to the UV radiation to be detected), the detector's response is maximized by utilizing the possibility of all available surfaces through photoelectric detection.

[0071] Additionally, the manufacturing process is simplified compared to existing technologies.

[0072] Furthermore, this disclosure enables the provision of a UV detector designed to detect radiation impacting two surfaces (front and back), which can be used, for example, in the manufacture of windows, eyeglasses, etc., for space stations and / or buildings.

[0073] Furthermore, according to this disclosure, it is provided that the shape and size of the area for detecting UV radiation can be modulated by guiding a laser beam as needed, i.e., without using photomask technology.

[0074] Finally, it is obvious that modifications and changes can be made to the description and illustrations herein without departing from the scope of this disclosure as defined in the appended claims.

[0075] A method for manufacturing a detector device (50; 150) for detecting UV radiation can be summarized as comprising the following steps: providing a SiC substrate (53) having a first conductivity (N) and a first concentration of dopant, the SiC substrate (53) being provided with a front side (53a) and a back side (53b) opposite to each other; forming a SiC drift layer (52) having a first conductivity (N) and a second concentration of dopant on the front side (53a) of the substrate (53), the second concentration of dopant being lower than the first concentration; forming a cathode terminal of the detector device (50) on the back side of the substrate (53); and forming the... The anode terminal of the detector device (50; 150) is characterized in that the step of forming the anode terminal includes implanting a dopant having a second conductivity (P) in a drift layer (52) to form a doped anode region (59), the second conductivity (P) being opposite to a first conductivity (N); and generating a first laser beam (82) toward the doped anode region (59) to heat the doped anode region (59) to a temperature between 1500°C and 2600°C to form a first ohmic contact region (60), the first ohmic contact region (60) comprising one or more carbon-rich layers in the doped anode region (59), specifically graphene and / or graphite layers.

[0076] The doped anode region (59) can extend in depth in the drift layer (52) starting from the top surface (52a) of the drift layer (52), and wherein the first ohmic contact region (60) has a top surface that coincides with the top surface (52a) of the drift layer (52).

[0077] Heating the doped anode region (59) with the first laser beam (82) can activate the doped material having the second conductivity (P) of the doped anode region (59).

[0078] The first laser beam (82) can be generated according to the following parameters: a wavelength between 290 nm and 370 nm; a pulse duration between 100 ns and 300 ns; and a pulse strength of 1.5 J / cm. 2 Up to 4.5 J / cm 2 The energy density between.

[0079] Forming the first ohmic contact region (60) may include forming the one or more carbon-rich layers only within the doped anode region (59).

[0080] The first ohmic contact region (60) may extend in the doped anode region (59) to a depth between 1 nm and 20 nm.

[0081] The step of forming a cathode terminal may include generating a second laser beam toward the back side (53b) of the substrate (53) to heat the substrate (53) to a temperature between 1500°C and 2600°C, thereby forming a second ohmic contact region (156) on the back side (53b) of the substrate (53) comprising one or more carbon-rich layers, particularly graphene and / or graphite layers.

[0082] The second laser beam can be generated according to the following parameters: a wavelength between 290 nm and 370 nm; a pulse duration between 100 ns and 300 ns; and a pulse strength between 3 and 4.5 J / cm². 2 The energy density between.

[0083] A detector device (50; 150) for detecting UV radiation can be generally defined as comprising: a SiC substrate (53) having a first conductivity (N) and a first concentration of dopant, the SiC substrate (53) being provided with a front side (53a) and a back side (53b) opposite to each other; a SiC drift layer (52) extending over the front side (53a) of the substrate (53), the SiC drift layer (52) having a first conductivity (N) and a second concentration of dopant, the second concentration of dopant being lower than the first concentration; a cathode terminal located on the back side of the substrate (53); and an anode terminal located in the drift layer (52), characterized in that the anode terminal comprises: a doped anode region (59) located in the drift layer (52), the doped anode region (59) comprising a dopant having a second conductivity (P) opposite to the first conductivity (N); and a first ohmic contact region (60) comprising one or more carbon-rich layers, particularly graphene and / or graphite layers and extending in the doped anode region (59).

[0084] The doped anode region (59) can extend in depth in the drift layer (52) starting from the top surface (52a) of the drift layer (52), and wherein the first ohmic contact region (60) has a top surface that coincides with the top surface (52a) of the drift layer (52).

[0085] The first ohmic contact region (60) may include one or more carbon-rich layers only within the doped anode region (59).

[0086] The first ohmic contact region (60) may extend in the doped anode region (59) to a depth between 1 nm and 20 nm.

[0087] The substrate (53) may be 4H-SiC.

[0088] The cathode terminal may include a second ohmic contact region (156) comprising one or more carbon-rich layers, specifically graphene and / or graphite layers, extending within the doped anode region (59).

[0089] The second ohmic contact area (156) may have a surface that coincides with the back side (53b) of the substrate (53).

[0090] The various embodiments described above can be combined to provide further embodiments. If it is necessary to employ concepts from various patents, applications, and publications to provide additional embodiments, aspects of the embodiments can be modified.

[0091] Based on the detailed description above, these and other changes can be made to the embodiments. Generally, the terminology used in the appended claims should not be construed as limiting the claims to the specific embodiments disclosed in the specification and claims, but should be interpreted to include all possible embodiments and the full scope of their equivalents claimed by such claims. Therefore, the claims are not limited by this disclosure.

Claims

1. A method comprising: The detector device for detecting UV radiation is manufactured using the following method: A drift layer of SiC with the first conductivity and a first concentration of dopant is formed on the front side of a silicon carbide (SiC) substrate having the first conductivity and a second concentration of dopant, wherein the second concentration of dopant is lower than the first concentration. The cathode terminal of the detector device is formed on the back side of the substrate; as well as The anode terminal of the detector device is formed in the drift layer, and forming the anode terminal includes: A doped anode region is formed by implanting a dopant having a second conductivity opposite to the first conductivity into the drift layer; as well as A first ohmic contact region comprising one or more carbon-rich layers is formed in the doped anode region using a laser.

2. The method of claim 1, wherein the doped anode region extends in depth within the drift layer, starting from the top surface of the drift layer. Furthermore, the first ohmic contact area has a top surface that coincides with the top surface of the drift layer.

3. The method of claim 1, wherein forming the first ohmic contact region comprises: By using a laser to generate a first laser beam toward the doped anode region and activating the dopant material having the second conductivity in the doped anode region, the doped anode region is heated to a temperature in the range of 1500°C to 2600°C.

4. The method of claim 3, wherein generating the first laser beam comprises: Use wavelengths in the range of 290nm to 370nm; Use pulse durations in the range of 100ns to 300ns; as well as Use 1.5J / cm 2 Up to 4.5 J / cm 2 Energy density within the range.

5. The method of claim 1, wherein forming the first ohmic contact region comprises: The one or more carbon-rich layers are formed only within the doped anode region.

6. The method of claim 1, wherein the first ohmic contact region extends to a depth in the doped anode region in the range of 1 nm to 20 nm.

7. The method of claim 3, wherein forming the cathode terminal comprises: By generating a second laser beam toward the back side of the substrate, the substrate is heated to a temperature in the range of 1500°C to 2600°C, and a second ohmic contact region comprising one or more carbon-rich layers is formed on the back side of the substrate.

8. The method of claim 7, wherein generating the second laser beam comprises: Use wavelengths in the range of 290nm to 370nm; Use pulse durations in the range of 100ns to 300ns; as well as Using 3J / cm 2 Up to 4.5 J / cm 2 Energy density within the range.

9. A UV detector device, comprising: A silicon carbide (SiC) substrate having a first conductivity and a first concentration of doped material, the SiC substrate having a front side and a back side opposite to each other; A SiC drift layer extends over the front side of the substrate, having the first conductivity and a second concentration of dopant, wherein the second concentration of dopant is lower than the first concentration. A cathode terminal located on the back side of the substrate; as well as Anode terminals located in the drift layer, wherein the anode terminals include: The doped anode region located in the drift layer includes a dopant having a second conductivity opposite to the first conductivity; as well as The first ohmic contact region includes one or more carbon-rich layers, and the first ohmic contact region extends in the doped anode region.

10. The device of claim 9, wherein the doped anode region extends in depth within the drift layer, starting from the top surface of the drift layer. Furthermore, the first ohmic contact area has a top surface that coincides with the top surface of the drift layer.

11. The device of claim 9, wherein the first ohmic contact region comprises the one or more carbon-rich layers only within the doped anode region.

12. The device of claim 9, wherein the first ohmic contact region extends to a depth in the doped anode region in the range of 1 nm to 20 nm.

13. The device according to claim 9, wherein the substrate is 4H-SiC.

14. The device of claim 9, wherein the cathode terminal includes a second ohmic contact region, the second ohmic contact region including one or more carbon-rich layers extending in the doped anode region.

15. The device of claim 14, wherein the second ohmic contact region has a surface that coincides with the back side of the substrate.

16. A device comprising: A silicon carbide substrate having a first dopant type with a first doping concentration, the silicon carbide substrate including a first surface opposite to a second surface; A drift layer located on the first surface of the silicon carbide substrate, the drift layer having the first doping type, the drift layer having a first surface spaced apart from the first surface of the silicon carbide substrate; An anode of a second doping type is located between the first surface of the drift layer and the first surface of the silicon carbide substrate in the drift layer. as well as A first ohmic contact in the anode between the first surface of the drift layer and the first surface of the silicon carbide substrate, the first ohmic contact comprising carbon.

17. The device of claim 16, further comprising a second ohmic contact on the second surface of the silicon carbide substrate, the second ohmic contact comprising carbon.

18. The device of claim 16, wherein the anode covers a first region at the first surface of the drift layer, and the first ohmic contact has the first region.

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