Nitride-based semiconductor device

Abstract

According to one aspect of the present invention, a nitride-based semiconductor device comprises: a substrate; a nucleation layer stacked on the substrate; a buffer layer stacked on the nucleation layer; a channel layer which is stacked on the buffer layer and provides an electron transport path; and a barrier layer stacked on the channel layer such that the electron transport path is formed. The barrier layer includes nitrogen, gallium, aluminum, and oxygen, and the concentration of oxygen at the upper end of the barrier layer is smaller than the concentration of aluminum at the upper end of the barrier layer.

Description

Nitride-based semiconductor devices

[0001] The present invention relates to a nitride-based semiconductor device. The present invention relates to the development of gallium nitride (GaN)-based 150nm process technology and application system (3.5km-class fixed drone detection radar) (No. 9991008828, 22-CM-TN-15) of a research project conducted in 2022 with funding from the Ministry of Trade, Industry and Energy and the Defense Acquisition Program Administration (government) and supported by the Agency for Defense Development's Civil-Military Cooperation Promotion Agency.

[0002] Due to the advancement of information and communication technology, there is an increasing need for high-voltage semiconductor devices capable of operating in high-speed switching or high-voltage environments. Accordingly, recently introduced gallium nitride-based semiconductor devices offer the advantage of enabling high-speed switching compared to conventional silicon-based devices, making them suitable for ultra-high-speed signal processing; furthermore, they can be applied to high-voltage environments thanks to the inherent high voltage resistance of the material itself.

[0003] In the case of a high electron mobility transistor (HEMT), which is a semiconductor device using gallium nitride, the electron mobility can be increased by utilizing a two-dimensional electron gas (2DEG) generated at the interface between heterogeneous materials, which has the advantage of being suitable for high-speed signal transmission.

[0004] Meanwhile, semiconductor devices are manufactured by stacking different materials on top of a substrate. For example, a buffer layer, a channel layer, a barrier layer, etc., may be stacked on top of the substrate, and each layer may contain different materials. There is a problem in that the substrate may bend, deform, or crack due to the different lattice constants and coefficients of thermal expansion between the materials constituting each layer stacked on top of the substrate in a semiconductor device. If the substrate bends or deforms, it cannot firmly support the materials on top, and in the case of severe bending or deformation, the substrate may break.

[0005] An embodiment of the present invention is to provide a nitride-based semiconductor device in which defect formation can be minimized.

[0006] According to one aspect of the present invention, a nitride-based semiconductor device may be provided, comprising: a substrate; a nucleus layer stacked on the substrate; a buffer layer stacked on the nucleus layer; a channel layer stacked on the buffer layer and providing an electron movement path; and a barrier layer stacked on the channel layer to form the electron movement path, wherein the barrier layer comprises nitrogen, gallium, aluminum, and oxygen, and the concentration of oxygen at the top of the barrier layer is smaller than the concentration of aluminum at the top of the barrier layer.

[0007] In addition, a nitride-based semiconductor device may be provided in which the average concentration of nitrogen in the barrier layer is greater than the average concentration of gallium, aluminum, and oxygen, respectively, in the barrier layer.

[0008] In addition, a nitride-based semiconductor device may be provided in which the average concentration of gallium in the barrier layer is greater than the average concentration of aluminum and oxygen, respectively, in the barrier layer.

[0009] In addition, a nitride-based semiconductor device may be provided in which the average concentration of aluminum in the barrier layer is greater than the average concentration of oxygen in the barrier layer.

[0010] Additionally, a nitride-based semiconductor device may be provided, wherein the channel layer comprises gallium and nitrogen, and the average concentration of nitrogen in the barrier layer is lower than the average concentration of nitrogen in the channel layer.

[0011] In addition, a nitride-based semiconductor device may be provided in which the average gallium concentration of the barrier layer is lower than the average gallium concentration of the channel layer.

[0012] Additionally, a nitride-based semiconductor device may be provided, wherein the barrier layer comprises a transition region, a first region disposed above the transition region, a second region disposed above the first region, and a third region, wherein the transition region is stacked on the channel layer, and the average gallium concentration of the transition region is greater than the average gallium concentration of each of the third region, the second region, and the first region.

[0013] In addition, a nitride-based semiconductor device may be provided in which the concentration of gallium in the transition region decreases as it approaches the first region.

[0014] In addition, a nitride-based semiconductor device may be provided in which the concentration of aluminum in the transition region increases as it approaches the first region.

[0015] Additionally, a nitride-based semiconductor device may be provided in which the concentration of gallium at the top of the first region and the concentration of gallium at the bottom of the first region are smaller than the concentration of gallium at the center of the first region.

[0016] In addition, a nitride-based semiconductor device may be provided in which the concentration of gallium in the second region increases as it moves toward the third region.

[0017] In addition, a nitride-based semiconductor device may be provided in which the concentration of aluminum in the second region decreases as it moves toward the third region.

[0018] In addition, a nitride-based semiconductor device may be provided in which the concentration of gallium in the third region decreases as it moves toward the top of the third region.

[0019] In addition, a nitride-based semiconductor device may be provided in which the oxygen concentration in the third region increases as it moves toward the top of the third region.

[0020] In addition, a nitride-based semiconductor device may be provided in which the concentration of aluminum in the third region decreases as it moves toward the top of the third region.

[0021] Additionally, a nitride-based semiconductor device may be provided in which the gallium concentration at the top of the second region is higher than the gallium concentration in the first region, and the gallium concentration at the top of the second region is lower than the gallium concentration at the bottom of the transition region.

[0022] In addition, a nitride-based semiconductor device may be provided in which the average oxygen concentration of the second region is lower than the average oxygen concentration of the third region.

[0023] In addition, a nitride-based semiconductor device may be provided in which the concentration of gallium at the top of the second region is smaller than the concentration of gallium at the bottom of the transition region.

[0024] Additionally, a nitride-based semiconductor device may be provided, comprising: a substrate; a nucleus layer stacked on the substrate; a buffer layer stacked on the nucleus layer; a channel layer stacked on the buffer layer and providing an electron transport path; and a barrier layer including nitrogen, gallium, aluminum, and oxygen, stacked on the channel layer, and for inducing the formation of a two-dimensional electron gas, wherein the barrier layer includes a transition region, a first region disposed above the transition region, a second region disposed above the first region, and a third region, wherein the concentration of gallium in the second region increases as it moves toward the third region, the concentration of aluminum in the second region decreases as it moves toward the third region, and the absolute value of the rate of change of gallium concentration in the second region is greater than the absolute value of the rate of change of aluminum concentration in the second region.

[0025] Additionally, a nitride-based semiconductor device may be provided, comprising: a substrate; a nucleus layer stacked on the substrate; a buffer layer stacked on the nucleus layer; a channel layer stacked on the buffer layer and providing an electron transport path; and a barrier layer stacked on the channel layer and for inducing the formation of a two-dimensional electron gas, wherein the barrier layer comprises a transition region, a first region disposed above the transition region, a second region disposed above the first region, and a third region, wherein the concentration of gallium at the center of the first region is smaller than the concentration of gallium at either the top or bottom of the first region.

[0026] One embodiment of the present invention has the effect that the formation of defects (cracks) in a nitride-based semiconductor device can be minimized by the buffer layer, channel layer, and barrier layer.

[0027] In addition, one embodiment of the present invention has the effect that leakage current in a nitride-based semiconductor device can be suppressed by the buffer layer, channel layer, and barrier layer.

[0028] In addition, one embodiment of the present invention has the effect that signal distortion in a nitride-based semiconductor device can be reduced by the buffer layer, channel layer, and barrier layer.

[0029] FIG. 1 is a diagram showing a nitride-based semiconductor device according to one embodiment of the present invention.

[0030] FIG. 2 is an SEM image of a channel layer and a barrier layer of a nitride-based semiconductor device according to one embodiment of the present invention.

[0031] FIG. 3 is a diagram showing the transition region, first region, second region, and third region of the barrier layer of the nitride-based semiconductor device of FIG. 1.

[0032] Figure 4 is a graph showing a first example of the concentrations of gallium, nitrogen, aluminum, and oxygen included in the barrier layer of the nitride-based semiconductor device of Figure 3.

[0033] Figure 5 is a graph showing a second example of the concentrations of gallium, nitrogen, aluminum, and oxygen included in the barrier layer of the nitride-based semiconductor device of Figure 3.

[0034] Figure 6 is a graph showing a third example of the concentrations of gallium, nitrogen, aluminum, and oxygen included in the barrier layer of the nitride-based semiconductor device of Figure 3.

[0035] FIG. 7 is a diagram showing a first electrode, a second electrode, and a third electrode disposed on the upper part of a nitride-based semiconductor device according to one embodiment of the present invention.

[0036] In the following description, numerous specific details are described for the purpose of explanation and to provide a complete understanding of the various embodiments or implementations of the present disclosure. As used herein, “Embodiments” and “Implementations” are interchangeable terms indicating non-limiting examples of devices or methods utilizing one or more of the concepts of the invention disclosed herein. However, it will be apparent that various embodiments may be implemented without utilizing these specific details or by utilizing one or more equivalent arrangements. In other examples, known structures and devices are illustrated in block diagram form to avoid unnecessarily obscuring the various embodiments. Furthermore, while various embodiments may differ from one another, they do not need to be exclusive. For example, specific shapes, configurations, and characteristics of an embodiment may be used or implemented in other embodiments without departing from the scope of the concept of the invention.

[0037] Unless otherwise specified, the illustrated embodiments should be understood as providing exemplary features of varying details in some ways in which the concept of the present invention can actually be realized. Therefore, unless otherwise specified, features, components, modules, layers, membranes, panels, regions and / or modes of various embodiments (hereinafter referred to individually or collectively as “elements”) may be combined, separated, interchanged, and / or rearranged differently without departing from the scope of the concept of the present invention.

[0038] The use of cross-hatching and / or shading in the attached drawings is generally provided to clarify the boundaries between adjacent elements. As such, the presence or absence of cross-hatching or shading, unless otherwise specified, does not imply or indicate any preference or requirement regarding the specific material, material properties, dimensions, proportions, commonalities between the exemplified elements, or any other features, attributes, and characteristics of the elements. Additionally, in the attached drawings, the size and relative size of the elements may be exaggerated for clarity and / or illustrative purposes. When embodiments are implemented differently, specific process sequences may be performed differently from the described order. For example, two consecutively described processes may be performed substantially simultaneously or in an order opposite to the described order. Also, the same reference numerals indicate the same elements.

[0039] When an element such as a layer is referred to as being "on", "connected to," or "coupled to" another element or layer, said element may be directly on, connected to, or coupled to the other element or layer, or an interposed element or layer may exist. However, when an element or layer is referred to as being "directly on", "directly connected to," or "directly coupled to" another element or layer, no interposed element or layer exists. To this end, the term "connected" may refer to a physical, electrical, and / or fluid connection with or without an interposed element. Furthermore, the DR1-axis, DR2-axis, and DR3-axis are not limited to the three axes of an orthogonal coordinate system, such as the x, y, and z axes, and may be interpreted in a broader sense. For example, the DR1-axis, DR2-axis, and DR3-axis may be perpendicular to each other, or they may represent different directions that are not perpendicular to each other. For the purposes of this disclosure, “one or more of X, Y, and Z” and “one or more selected from the group consisting of X, Y, and Z” may be interpreted as only X, only Y, only Z, or any combination of two or more of X, Y, and Z, such as, for example, XYZ, XYY, YZ, and ZZ. As used herein, the term “and / or” includes any and all combinations of one or more of the associated listed articles.

[0040] Although terms such as “first,” “second,” etc., may be used herein to describe various forms of elements, these elements shall not be limited by these terms. These terms are used to distinguish one element from another. Therefore, the first element discussed below may be named the second element without departing from the teachings of the present disclosure.

[0041] Spatially relative terms such as “below,” “under,” “immediately below,” “lower,” “above,” “upper,” “upper,” “higher,” and “side” (e.g., as in “side wall”) may be used for descriptive purposes and thereby to describe the relationship between one element and another element(s) as illustrated in the drawings. Spatially relative terms are intended to include different orientations of the device in use, operation, and / or manufacture in addition to the orientations illustrated in the drawings. For example, if the device in the drawings is inverted, the element described as “below” or “under” another element or feature will be oriented “above” the other element or feature. Therefore, the exemplary term “below” may include both upper and lower orientations. Additionally, the device may be oriented differently (e.g., rotated 90° or oriented in a different orientation), and thus, spatially relative descriptors used herein may also be interpreted accordingly.

[0042] The technical terms used in this specification are intended to describe specific embodiments and are not limiting. The singular form used in this specification also includes the plural form unless the context clearly indicates otherwise. Additionally, the terms “comprising,” “comprising,” “comprising,” and / or “comprising” used in this specification specify the presence of the mentioned features, integers, steps, operations, elements, components, and / or groups thereof, but do not exclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and / or groups thereof. Furthermore, the terms “substantially,” “about,” and other similar terms used in this specification are used to indicate approximation rather than degree, and are used to describe inherent deviations of measured, calculated, and / or provided values ​​that may be recognized by a person of ordinary knowledge in the art.

[0043] Various embodiments are described below with reference to cross-sectional and / or exploded drawings, which are schematic examples of idealized embodiments and / or intermediate structures. As such, variations from the shapes in the drawings may be expected, for example, as a result of manufacturing techniques and / or tolerances. Therefore, the embodiments disclosed herein should not be interpreted as being limited to the shapes of specific illustrated regions, but should be interpreted to include, for example, deviations in shape resulting from manufacturing. In this way, the regions illustrated in the drawings may be schematic in nature, and the shapes of these regions may not reflect the actual shapes of the regions of the device, and thus are not intended to have a limiting meaning.

[0044] As is customary in the art, some embodiments may be illustrated and described in the accompanying drawings in terms of functional blocks, units, and / or modules. Those skilled in the art will understand that these blocks, units, and / or modules are physically implemented by electronic (or optical) circuits, such as logic circuits, discrete components, microprocessors, wiring circuits, memory elements, and wiring connections, formed using semiconductor-based manufacturing technology or other manufacturing technology. Where blocks, units, and / or modules are implemented by microprocessors or other similar hardware, they may be programmed and controlled using software (e.g., microcode) to perform the various functions discussed herein, and may optionally be driven by firmware and / or software. Additionally, each block, unit, and / or module may be implemented by dedicated hardware, or as a combination of dedicated hardware for performing some functions and a processor for performing other functions (e.g., one or more programmed processors and associated circuits). Additionally, each of the blocks, units, and / or modules of some embodiments may be physically separated into two or more interacting and individual blocks, units, and / or modules without departing from the scope of the concept of the present invention. Additionally, the blocks, units, and / or modules of some embodiments may be physically combined into more complex blocks, units, and / or modules without departing from the scope of the concept of the present invention.

[0045] Unless otherwise defined, all terms used herein (including technical or scientific terms) have the same meaning as commonly understood by those skilled in the art to which this disclosure pertains. Terms such as those defined in commonly used dictionaries should be interpreted as having a meaning consistent with that meaning in the context of the relevant technology, and should not be interpreted in an ideal or overly formal sense unless explicitly defined in this specification.

[0046] A nitride-based semiconductor device (1) according to one embodiment of the present invention will be described below.

[0047] Referring to FIGS. 1 and 2, a nitride-based semiconductor device (1) according to one embodiment of the present invention can be used as a component such as an electronic circuit by utilizing the electrical conductivity characteristics of the semiconductor. The nitride-based semiconductor device (1) may include a substrate (100), a nucleus layer (200), a buffer layer (300), a channel layer (400), and a barrier layer (500).

[0048] The substrate (100) may support one or more of a core layer (200), a buffer layer (300), a channel layer (400), and a barrier layer (500). The substrate (100) may be N-type or P-type and may include various materials. For example, the substrate (100) may be one of an insulating substrate, a sapphire substrate, a GaN substrate, a SiC substrate, and a Si substrate. Additionally, the thickness of the substrate (100) may be 300 to 700 μm. Furthermore, various types of substrates (100) may be applicable to the nitride-based semiconductor device (1) according to one embodiment of the present invention.

[0049] The nucleation layer (200) can be laminated onto the substrate (100). The nucleation layer (200) can grow a nitride-based semiconductor material. In other words, the nucleation layer (200) can be placed on the substrate (100) to grow one or more of a buffer layer (300), a channel layer (400), and a barrier layer (500). The nucleation layer (200) can serve to minimize lattice mismatch between the substrate (100) and the buffer layer (300), relieve stress, and reduce defect density. Additionally, the nucleation layer (200) can increase the stability of the device by reducing thermal stress between the substrate (100) and the buffer layer (300). Furthermore, the nucleation layer (200) can minimize surface roughness of the substrate (100). Additionally, the nucleus layer (200) can serve to grow the layer formed on the substrate (100) in an appropriate crystal direction, thereby improving the electrical and optical properties of the nitride-based semiconductor device (1). The nucleus layer (200) may have a thickness of 100 nm or less.

[0050] A buffer layer (300) may be deposited on a core layer (200). This buffer layer (300) may be a layer composed of GaN doped with C or Fe. Additionally, the buffer layer (300) may be a semi-insulation GaN layer. The concentration of Fe in the buffer layer (300) may be 1016 to 1019 at%. The concentration of C or Fe in the buffer layer (300) may decrease to 1016 to 1017 at% as it approaches the channel layer (400). If the concentration of C or Fe in the buffer layer (300) decreases as it approaches the channel layer (400), defect formation may be minimized. The concentration of C or Fe in the buffer layer (300) may be 2E16 to 3E19 atoms / cm² as it is separated from the channel layer (400). 3It can be increased. If the concentration of C or Fe in the buffer layer (300) increases as it moves away from the channel layer (400), the device (1) can secure semi-insulating characteristics. In addition, since the buffer layer (300) can have semi-insulating characteristics, it can serve to insulate the substrate (100) while suppressing leakage current. Furthermore, the buffer layer (300) can suppress current leakage while allowing a small amount of current, thereby reducing signal distortion in high-frequency devices. The buffer layer (300) may include a region of 500 nm or more in which the concentration of C or Fe is maintained substantially constant. Therefore, electrical characteristics can be maintained stably by preventing resistance bias.

[0051] The rate of change in concentration of C or Fe at the interface between the buffer layer (300) and the channel layer (400) may be greater than the rate of change in concentration of C or Fe at the interface between the buffer layer (300) and the nucleus layer (200). Thus, a higher response speed can be achieved. Here, the rate of change in concentration may be the absolute value of the maximum concentration of C or the maximum concentration of Fe at the interface divided by the minimum concentration of C or the minimum concentration of Fe.

[0052] The buffer layer (300) may be larger than the thickness of the channel layer (400) and the barrier layer (500). The thickness of the buffer layer (300) may be formed to be 5 μm or less.

[0053] The buffer layer (300) may include a first region with a relatively high doping concentration and a second region with a relatively low doping concentration. The first region of the buffer layer (300) may be positioned close to the channel layer (400), and the second region of the buffer layer (300) may be positioned close to the nucleus layer (200). The difference in doping concentration between the first region and the second region of the buffer layer (300) may be 100 times or more. Additionally, the thickness of the second region of the buffer layer (300) may be greater than the thickness of the first region of the buffer layer (300), but less than 1.7 times the thickness of the first region of the buffer layer (300). Thus, the first region of the buffer layer (300) is formed on the second region of the buffer layer (300), which has improved thin film quality, thereby preventing the dopant of the first region from acting as a defect.

[0054] The oxygen concentration of the buffer layer (300) may be lower than the oxygen concentration of the nuclear layer (200). Therefore, it is possible to prevent the dopant of the buffer layer (300) from binding with oxygen and becoming inactive. The oxygen concentration of the nuclear layer (200) is 1E19 atoms / cm² 3 It may be more than, and the oxygen concentration of the buffer layer (300) is 1E19 atoms / cm 3 It may be less than

[0055] The channel layer (400) may be a region where the flow of electrons and current occurs. This channel layer (400) may include a compound of the III-V group. For example, the channel layer (400) may include a GaN-based material. This channel layer (400) may be undoped or doped with an unintended material, but it may also be a layer doped with one of the dopants C, Fe, Mg, and Mn. The channel layer (400) may be placed on the upper side of the buffer layer (300). The channel layer (400) may be formed by one of the methods of organometallic vapor deposition (MOCVD), molecular beam epitaxial growth (MBE), and hydride vapor epitaxial growth (HVPE). The thickness of the channel layer (400) may be 2 μm or less. The channel layer (400) may be 0.005 to 0.02 times the thickness of the buffer layer (300). Therefore, since the distance between the electrode and the buffer layer (300), which will be described later, can be formed close, channel formation can be easy.

[0056] Additionally, an electron transport channel through which electrons move may be formed in the channel layer (400). The electron transport channel may be formed near the barrier layer (500) on the upper part of the channel layer (400). For example, a 2DEG (two-dimensional electron gas) may be formed as an electron transport channel on the upper part of the channel layer (400).

[0057] Referring further to FIGS. 3 through 6, the barrier layer (500) may be a layer that is stacked on the channel layer (400) to induce an electron transport channel of the channel layer (400). The electron transport channel may be formed in the channel layer (400) below the interface between the channel layer (400) and the barrier layer (500). The barrier layer (500) may include a material that has different polarization characteristics, an energy bandgap, and a lattice constant from the channel layer (400). Additionally, the barrier layer (500) may include a material that has a larger polarization rate and an energy bandgap than the channel layer (400). The barrier layer (500) may have a single-layer or multi-layer structure comprising one or more materials selected from nitrides including aluminum (Al), gallium (Ga), nitrogen (N), phosphorus (In), boron (B), and oxygen (O). For example, the barrier layer (500) may include one or more of various materials including AlGaN, AlInN, InGaN, AlN, AlInGaN, etc. The barrier layer (500) may be undoped or a layer doped with a predetermined impurity. The barrier layer (500) may be formed by one of the methods of organometallic vapor deposition (MOCVD), molecular beam epitaxial growth (MBE), and hydride vapor epitaxial growth (HVPE). The thickness of the barrier layer (500) may be 10 to 40 nm.

[0058] Additionally, the concentrations of nitrogen, gallium, aluminum, and oxygen in the barrier layer (500) may increase or decrease as they move toward the top of the barrier layer (500). Below, the average of each of nitrogen, gallium, aluminum, and oxygen may be the average of the concentrations of nitrogen, gallium, aluminum, and oxygen changing in the stacking direction. The bottom of the barrier layer (500) may be a point where the concentration of gallium is relatively low. For example, the difference in gallium concentration between the channel layer (400) and the barrier layer (500) may be 20% or more. Thus, a channel can be easily formed.

[0059] The average nitrogen concentration of the barrier layer (500) can be formed to be greater than the average concentration of gallium, aluminum, and oxygen, respectively, of the barrier layer (500). The average nitrogen concentration of the barrier layer (500) can be lower than the average nitrogen concentration of the channel layer (400). The nitrogen concentration of the barrier layer (500) can be 44 at% or more and 50 at% or less.

[0060] The average concentration of gallium in the barrier layer (500) can be formed to be greater than the average concentrations of aluminum and oxygen, respectively, in the barrier layer (500). Additionally, the average concentration of gallium in the barrier layer (500) can be lower than the average concentration of gallium in the channel layer (400). For example, the gallium concentration can be 30 at% or more and less than 50 at%.

[0061] The average concentration of aluminum in the barrier layer (500) can be formed to be greater than the average concentration of oxygen in the barrier layer (500). For example, the concentration of aluminum may be 0.1 at% or more and less than 20 at%. In addition, the concentration of oxygen may be 0.1 at% or more and 8 at% or less.

[0062] Additionally, the barrier layer (500) may include a transition region (510), a first region (520), a second region (530), and a third region (540).

[0063] A transition region (510) may be laminated on a channel layer (400). The transition region (510) may be a region that transitions from the channel layer (400) to a barrier layer (500). The concentration of one or more of nitrogen, gallium, aluminum, and oxygen in this transition region (510) may vary more significantly than in the first region (520), the second region (530), and the third region (540). The average gallium concentration in the transition region (510) may be formed to be greater than the average gallium concentration in each of the first region (520), the second region (530), and the third region (540). For example, the gallium concentration in the transition region (510) may be 34 at% or more and less than 50 at%. Or, the gallium concentration in the transition region (510) may be 25 at% or more and less than 50 at%. The concentration of gallium in the transition region (510) may decrease as it moves toward the first region (520). The concentration of gallium in the transition region (510) may increase as it moves toward the first region (520). The concentration of gallium at the bottom of the transition region (510) may be substantially the same as the concentration of gallium at the top of the channel layer (400). The concentration of gallium at the top of the transition region (510) may be linked to the concentration of gallium at the bottom of the first region (520) and may be the same as the concentration of gallium at the bottom of the first region (520). The absolute value of the rate of change of gallium in the transition region (510) may be formed to be greater than the absolute value of the rate of change of nitrogen in the transition region (510). A valley of gallium concentration in the barrier layer (500) may be formed in the transition region (510). The lowest concentration of gallium in the barrier layer (500) can be formed in the transition region (510).

[0064] The average nitrogen concentration in the transition region (510) may be formed to be greater than the average nitrogen concentration in each of the first region (520), the second region (530), and the third region (540). For example, the nitrogen concentration in the transition region (510) may be 45 at% or more and 50 at% or less. The nitrogen concentration in this transition region (510) may decrease as it moves toward the first region (520). Additionally, the nitrogen concentration at the bottom of the transition region (510) may be the same as the nitrogen concentration at the top of the channel layer (400). Also, the nitrogen concentration at the top of the transition region (510) may be the same as the nitrogen concentration at the bottom of the first region (520). A peak of nitrogen concentration in the barrier layer (500) may be formed in the transition region (510).

[0065] The maximum value of the aluminum concentration in the transition region (510) may be greater than the aluminum concentration in each of the first region (520), the second region (530), and the third region (540). Therefore, the response speed can be improved by forming a high energy barrier and preventing the channel path from spreading to other regions, thereby forming a short channel path. The aluminum concentration in the transition region (510) may increase and then decrease as it moves toward the first region (520). The aluminum concentration at the top of the transition region (510) may be the same as the aluminum concentration at the bottom of the first region (520). The absolute value of the rate of change of aluminum in the transition region (510) may be greater than the absolute value of the rate of change of nitrogen in the transition region (510). Here, the rate of change may be the difference between the maximum and minimum values ​​of the material in the corresponding region.

[0066] The average oxygen concentration in the transition region (510) can be formed to be smaller than the average oxygen concentration in each of the first region (520), the second region (530), and the third region (540). For example, the oxygen concentration in the transition region (510) can be 0.1 at% or more and 0.2 at% or less. Here, the oxygen concentration can be verified by Atom Probe Tomography (APT). By maintaining a low oxygen concentration, oxidation of the semiconductor layer can be prevented.

[0067] The first region (520) can be laminated to the transition region (510). The thickness of the first region (520) can be formed to be greater than the thickness of each of the transition region (510), the second region (530), and the third region (540). The concentration of gallium in the first region (520) can be formed as follows.

[0068] For example, the difference between the concentration of gallium at the top of the first region (520) and the concentration of gallium at the bottom of the first region (520) may be within 5 at%. In other words, the concentration of gallium in the first region (520) may increase from the bottom of the first region (520) to the center of the first region (520) and decrease from the center of the first region (520) to the top of the first region (520). The concentration of gallium in this first region (520) may be formed to be 32 at% or more and 38 at% or less.

[0069] As a second example, the gallium concentration at the top of the first region (520), the gallium concentration at the bottom of the first region (520), and the gallium concentration at the center of the first region (520) may be formed to be substantially the same. In other words, the gallium concentration in the first region (520) may be maintained substantially constant from the bottom of the first region (520) to the top of the first region (520). The difference in gallium concentration in the first region (520) may be within 3 at%. The gallium concentration in the first region (520) may be formed to be between 34 at% and 36 at%. Thus, lattice defects may be reduced, thereby reducing gate leakage current and improving frequency characteristics.

[0070] As a third example, the concentration of gallium at the top of the first region (520) and the concentration of gallium at the bottom of the first region (520) may be formed higher than the concentration of gallium at the center of the first region (520). In other words, the concentration of gallium in the first region (520) may decrease from the bottom of the first region (520) to the center of the first region (520) and increase from the center of the first region (520) to the top of the first region (520). Such a concentration of gallium in the first region (520) may be formed to be 34 at% or more and less than 38 at%.

[0071] The concentration of gallium at the bottom of the first region (520) may be the same as the concentration of gallium at the top of the transition region (510). The concentration of gallium at the top of the first region (520) may be the same as the concentration of gallium at the bottom of the second region (530).

[0072] The nitrogen concentration in the first region (520) may increase or decrease repeatedly or remain constant as it moves toward the second region (530). The nitrogen concentration in the first region (520) may be formed to be 43 at% or more and less than 48 at%. The nitrogen concentration at the bottom of the first region (520) may be the same as the nitrogen concentration at the top of the transition region (510). Additionally, the nitrogen concentration at the top of the first region (520) may be the same as the nitrogen concentration at the bottom of the second region (530).

[0073] The concentration of aluminum in the first region (520) may increase or decrease repeatedly or remain constant as it moves toward the second region (530). The average of the aluminum concentration in the first region (520) may be formed to be greater than the average of the aluminum concentrations in the transition region (510), the second region (530), and the third region (540), respectively. Here, the average may refer to the midpoint between the maximum and minimum values ​​of the material in the corresponding region. For example, the aluminum concentration in the first region (520) may be formed to be 16 at% or more and less than 20 at%. The aluminum concentration at the top of the first region (520) may be the same as the aluminum concentration at the bottom of the second region (530). The aluminum concentration at the bottom of the first region (520) may be the same as the aluminum concentration at the bottom of the transition region (510). The peak of the aluminum concentration of the barrier layer (500) may be formed in the transition region (510).

[0074] The oxygen concentration at the top of the first region (520) may be formed higher than the oxygen concentration at the bottom of the first region (520). The oxygen concentration at the top of the first region (520) may be the same as the oxygen concentration at the bottom of the second region (530). The oxygen concentration at the bottom of the first region (520) may be the same as the oxygen concentration at the top of the transition region (510). For example, the oxygen concentration of the first region (520) may be 0.1 at% or higher and 0.4 at% or lower. Here, the oxygen concentration can be verified by atomic probe tomography (APT). Oxidation of the transition region (510) can be prevented by maintaining a low oxygen concentration.

[0075] The second region (530) can be stacked on the first region (520). The gallium concentration in the second region (530) may increase as it moves toward the third region (540). For example, the gallium concentration in the second region (530) may be formed to be 33 at% or more and less than 40 at%. The gallium concentration at the bottom of the second region (530) may be the same as the gallium concentration at the top of the first region (520). Also, the gallium concentration at the top of the second region (530) may be the same as the gallium concentration at the bottom of the third region (540). Additionally, the gallium concentration at the top of the second region (530) may be higher than the gallium concentration in the first region (520). The concentration of gallium at the top of the second region (530) may be smaller than the concentration of gallium at the bottom of the transition region (510) and greater than the concentration of gallium at the top of the transition region (510). Additionally, the absolute value of the rate of change of the gallium concentration in the second region (530) may be formed to be greater than the absolute value of the rate of change of the aluminum concentration in the second region (530).

[0076] The nitrogen concentration at the bottom of the second region (530) may be lower than the nitrogen concentration at the top of the second region (530). In other words, the nitrogen concentration in the second region (530) may decrease in at least some parts as it moves toward the third region (540). For example, the nitrogen concentration in the second region (530) may be 44 at% or more and 50 at% or less. Also, the nitrogen concentration at the bottom of the second region (530) may be the same as the nitrogen concentration at the top of the first region (520).

[0077] The concentration of nitrogen at the top of the second region (530) may be the same as the concentration of nitrogen at the bottom of the third region (540). The concentration of aluminum in the second region (530) may decrease as it moves toward the third region (540). The rate of change of the aluminum concentration in this second region (530) may be greater than the rate of change of the aluminum concentration in the third region (540). Additionally, the absolute value of the rate of change of the aluminum concentration in the second region (530) may be smaller than the absolute value of the rate of change of the aluminum concentration in the transition region (510). The concentration of aluminum at the bottom of the second region (530) may be the same as the concentration of aluminum at the top of the first region (520). The concentration of aluminum at the top of the second region (530) may be the same as the concentration of aluminum at the bottom of the third region (540). For example, the concentration of aluminum in the second region (530) can be formed to be 15 at% or more and less than 20 at%.

[0078] The oxygen concentration in the second region (530) may increase as it moves toward the third region (540). The average oxygen concentration in the second region (530) may be lower than the average oxygen concentration in the third region (540). The rate of change of the oxygen concentration in the second region (530) may be smaller than the rate of change of the oxygen concentration in the third region (540). The oxygen concentration at the bottom of the second region (530) may be the same as the oxygen concentration at the top of the first region (520). The oxygen concentration at the top of the second region (530) may be the same as the oxygen concentration at the bottom of the third region (540). For example, the concentration in the second region (530) may be 0.2 at% or more and 1 at% or less. Here, the oxygen concentration can be verified by atomic probe tomography (APT).

[0079] The third region (540) may be laminated to the second region (530). The top of the third region (540) may be the top of the barrier layer (500). The gallium concentration in this third region (540) may decrease as it moves toward the top of the third region (540). The absolute value of the rate of change of the gallium concentration in this third region (540) may be greater than the absolute value of the rate of change of the aluminum concentration in this third region (540). The absolute value of the rate of change of the gallium concentration in this third region (540) may be greater than the absolute value of the rate of change of the nitrogen concentration in this third region (540). The gallium concentration at the top of the third region (540) may be smaller than the gallium concentration in the first region (520) and the gallium concentration in the transition region (510). For example, the concentration of gallium in the third region (540) may be 31 at% or more and less than 40 at%.

[0080] The nitrogen concentration in the third region (540) may increase as it moves toward the top of the third region (540). The nitrogen concentration at the top of the third region (540) may be greater than the nitrogen concentration in the second region (530) and the first region (520), and less than the nitrogen concentration at the bottom of the transition region (510). The nitrogen concentration at the bottom of the third region (540) may be equal to the nitrogen concentration at the top of the second region (530). For example, the nitrogen concentration in the third region (540) may be 45 at% or more and 49 at% or less.

[0081] The concentration of aluminum in the third region (540) may decrease as it moves toward the top of the third region (540). The concentration of aluminum at the top of the third region (540) may be smaller than the concentration of aluminum in the second region (530) and the first region (520), and larger than the concentration of aluminum at the bottom of the transition region (510). The concentration of aluminum at the bottom of the third region (540) may be equal to the concentration of aluminum at the top of the second region (530). The absolute value of the rate of change of the aluminum concentration in this third region (540) may be smaller than the absolute value of the rate of change of the oxygen concentration in the third region (540) and the absolute value of the rate of change of the gallium concentration in the third region (540). For example, the concentration of aluminum in the third region (540) may be 12 at% or more and 16 at% or less.

[0082] The oxygen concentration in the third region (540) may increase as it moves toward the top of the third region (540). The oxygen concentration at the top of the third region (540) may be greater than the oxygen concentration in the second region (530), the first region (520), and the transition region (510). The oxygen concentration at the bottom of the third region (540) may be the same as the oxygen concentration at the top of the second region (530). For example, the oxygen concentration in the third region (540) may be 1 at% or more and 8 at% or less.

[0083] The bandgap energy of the third region (540) may decrease as it moves toward the top of the third region (540). The bandgap energy of the third region (540) may vary within the range of 3.96 to 4.52 eV. Here, the bandgap energy can be calculated as Eg(AlxGa(1-x)N)=xEg(AlN)+(1-x)Eg(GaN), (0≤x≤1, Eg(AlN)=6.2, Eg(GaN)=3.4). The difference between the bandgap energy (E1) at the top surface of the third region (540) and the bandgap energy (E2) at the region where the third region (540) contacts the second region (530) may be within 0.6 eV. Thus, the 2DEG formation rate can be increased by keeping the bandgap energy difference within 0.6 eV.

[0084] Referring to FIG. 7, the nitride-based semiconductor device (1) may include a first electrode (601), a second electrode (602), and a third electrode (603). The first electrode (601), the second electrode (602), and the third electrode (603) may be positioned on the upper surface of the nitride-based semiconductor device (1) and may be electrically connected to the nitride-based semiconductor device (1). The first electrode (601) may be connected to a barrier layer (500) and a channel layer (400). The third electrode (603) may be connected to a barrier layer (500). The lower surfaces of the first electrode (601) and the second electrode (602) may be positioned lower than the lower surface of the third electrode (603). The lower surfaces of the first electrode (601) and the second electrode (602) may be positioned lower than the lower surface of the barrier layer (500) and lower than the upper surface of the channel layer (400). Additionally, the third electrode (603) may be connected to the upper side of the barrier layer (500). The first electrode (601) may function as a source electrode, the second electrode (602) as a drain electrode, and the third electrode (603) as a gate electrode.

[0085] Additionally, the nitride-based semiconductor device (1) may further include an insulating layer (700). The insulating layer (700) may be disposed on the upper surface of the nitride-based semiconductor device (1). The insulating layer (700) may be a material having electrical insulating properties such as SixOy or SixNy. The insulating layer (700) may include an opening that exposes the upper surface of the semiconductor device (1). The upper surface of the barrier layer (500) may be exposed through the opening of the insulating layer (700). Thus, the upper surface of the nitride-based semiconductor device (1) exposed through the opening and the third electrode (603) may be electrically connected. The upper surface of the barrier layer (500) and the third electrode (603) may be connected. The width of the lower surface of the third electrode (603) may be smaller than the width of the upper surface of the third electrode (603). Thus, the response speed can be improved. The width of the lower surface of the third electrode (603) may be smaller than the thickness of the barrier layer (500). Additionally, the width of the lower surface of the third electrode (603) may be smaller than the thickness of the transition region (510). Additionally, the width of the lower surface of the third electrode (603) may be larger than the thickness of the first region (520) of the barrier layer (500). Thus, by bringing the distance between the third electrode (603) and the channel layer (400) closer, the response speed of the nitride-based semiconductor device (1) can be improved, and the response precision of the device can be increased.

[0086] Hereinafter, the operation and effects of a nitride-based semiconductor device (1) according to one embodiment of the present invention will be described.

[0087] The nitride-based semiconductor device (1) can minimize defect formation through the buffer layer (300), channel layer (400), and barrier layer (500).

[0088] In addition, the nitride-based semiconductor device (1) can suppress leakage current by means of a buffer layer (300), a channel layer (400), and a barrier layer (500).

[0089] In addition, the nitride-based semiconductor device (1) can allow a small amount of current while suppressing current leakage through the buffer layer (300), channel layer (400), and barrier layer (500), thereby reducing signal distortion in the high-frequency device.

[0090] In addition, the nitride-based semiconductor device (1) can increase the 2DEG formation speed by means of a buffer layer (300), a channel layer (400), and a barrier layer (500).

[0091] Although the embodiments of the present invention have been described above as specific embodiments, they are merely examples and the present invention is not limited thereto, but should be interpreted as having the broadest scope in accordance with the technical concept disclosed in this specification. Those skilled in the art may implement patterns of shapes not specified by combining or substituting the disclosed embodiments, and this also does not deviate from the scope of the present invention. Furthermore, those skilled in the art may easily modify or alter the disclosed embodiments based on this specification, and it is evident that such modifications or alterations also fall within the scope of the rights of the present invention.

Claims

1. Substrate; A nucleus layer stacked on the above substrate; A buffer layer stacked on the above-mentioned core layer; A channel layer stacked on the above buffer layer and providing an electron movement path; and It includes a barrier layer stacked on the channel layer to form the above electron movement path, The above barrier layer comprises nitrogen, gallium, aluminum, and oxygen, and The oxygen concentration at the top of the barrier layer is smaller than the aluminum concentration at the top of the barrier layer, Nitride-based semiconductor device.

2. In Paragraph 1, The average concentration of nitrogen in the barrier layer is greater than the average concentration of gallium, aluminum, and oxygen, respectively, in the barrier layer. Nitride-based semiconductor device.

3. In Paragraph 1, The average concentration of gallium in the barrier layer is greater than the average concentration of aluminum and oxygen, respectively, in the barrier layer. Nitride-based semiconductor device.

4. In Paragraph 1, The average concentration of aluminum in the barrier layer is greater than the average concentration of oxygen in the barrier layer. Nitride-based semiconductor device.

5. In Paragraph 1, The above channel layer contains gallium and nitrogen, and The average nitrogen concentration of the barrier layer is lower than the average nitrogen concentration of the channel layer. Nitride-based semiconductor device.

6. In Paragraph 1, The average gallium concentration of the barrier layer is lower than the average gallium concentration of the channel layer. Nitride-based semiconductor device.

7. In Paragraph 1, The barrier layer comprises a transition region, a first region disposed above the transition region, a second region disposed above the first region, and a third region. The above transition region is stacked on the channel layer, and The average gallium concentration in the above transition region is greater than the average gallium concentration in each of the above third region, the above second region, and the above first region. Nitride-based semiconductor device.

8. In Paragraph 7, The concentration of gallium in the above transition region decreases as it approaches the first region, Nitride-based semiconductor device.

9. In Paragraph 7, The concentration of aluminum in the above transition region increases as it moves toward the above first region, Nitride-based semiconductor device.

10. In Paragraph 7, The concentration of gallium at the top of the first region and the concentration of gallium at the bottom of the first region are smaller than the concentration of gallium at the center of the first region. Nitride-based semiconductor device.

11. In Paragraph 7, The concentration of gallium in the second region above increases as it moves toward the third region, Nitride-based semiconductor device.

12. In Paragraph 7, The concentration of aluminum in the second region decreases as it moves toward the third region. Nitride-based semiconductor device.

13. In Paragraph 7, The concentration of gallium in the third region decreases as it moves toward the top of the third region. Nitride-based semiconductor device.

14. In Paragraph 7, The oxygen concentration in the third region increases as it moves toward the top of the third region, Nitride-based semiconductor device.

15. In Paragraph 7, The concentration of aluminum in the third region decreases as it moves toward the top of the third region. Nitride-based semiconductor device.

16. In Paragraph 7, The concentration of gallium at the top of the second region is higher than the concentration of gallium in the first region, and The gallium concentration at the top of the second region is smaller than the gallium concentration at the bottom of the transition region. Nitride-based semiconductor device.

17. In Paragraph 7, The average oxygen concentration in the second region is lower than the average oxygen concentration in the third region. Nitride-based semiconductor device.

18. In Paragraph 7, The gallium concentration at the top of the second region is smaller than the gallium concentration at the bottom of the transition region. Nitride-based semiconductor device.

19. Substrate; A nucleus layer stacked on the above substrate; A buffer layer stacked on the above-mentioned core layer; A channel layer stacked on the above buffer layer and providing an electron movement path; and It comprises nitrogen, gallium, aluminum, and oxygen, and includes a barrier layer laminated on the channel layer and configured to induce the formation of a two-dimensional electron gas. The barrier layer comprises a transition region, a first region disposed above the transition region, a second region disposed above the first region, and a third region. The concentration of gallium in the second region above increases as it moves toward the third region, and The concentration of aluminum in the second region decreases as it moves toward the third region, and The absolute value of the rate of change in gallium concentration in the second region is greater than the absolute value of the rate of change in aluminum concentration in the second region. Nitride-based semiconductor device.

20. Substrate; A nucleus layer stacked on the above substrate; A buffer layer stacked on the above-mentioned core layer; A channel layer stacked on the above buffer layer and providing an electron movement path; and It comprises nitrogen, gallium, aluminum, and oxygen, and includes a barrier layer laminated on the channel layer and configured to induce the formation of a two-dimensional electron gas. The barrier layer comprises a transition region, a first region disposed above the transition region, a second region disposed above the first region, and a third region. The gallium concentration at the center of the first region is smaller than the gallium concentration at either the top or bottom of the first region. Nitride-based semiconductor device.

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