Semiconductor device

Abstract

A semiconductor device includes a channel layer, a barrier layer over the channel layer and having a material of a different energy band gap than the channel layer, a source electrode and a drain electrode on the channel layer, a gate electrode over the barrier layer between the source electrode and the drain electrode, and a gate semiconductor layer between the barrier layer and the gate electrode. A width of the gate electrode is smaller than a width of the gate semiconductor layer at a junction surface of the gate electrode and the gate semiconductor layer.

Description

[0001] Cross - reference to related applications

[0002] This application claims priority to Korean Patent Application No. 10 - 2023 - 0194756, filed with the Korean Intellectual Property Office on December 28, 2023, the disclosure of which is incorporated herein by reference in its entirety. Technical field

[0003] This disclosure relates to a semiconductor device. Background art

[0004] In modern society, semiconductor devices are electronic components that utilize the electronic properties of semiconductor materials. Semiconductor materials have an electrical conductivity that lies between that of conductors and insulators, making them useful in a wide range of electronic circuits.

[0005] Power semiconductor devices are semiconductor devices designed to handle high voltages and high currents without degrading performance. Power semiconductor devices can be used in transportation systems (such as electric vehicles, railways, and trams), renewable energy systems (such as solar power generation and wind power generation), and mobile devices. Power semiconductor devices perform functions such as power conversion and control in large - scale power systems or high - power electronic devices. Power semiconductor devices are capable of handling high power and have high durability. For example, power semiconductor devices can handle voltages from several hundred volts to several thousand volts and currents from several tens of amperes to several thousand amperes. Power semiconductor devices can improve the efficiency of electrical energy by minimizing power losses. In addition, they can operate stably even in environments such as high temperatures.

[0006] Examples of power semiconductor devices include silicon carbide (SiC) power semiconductor devices and gallium nitride (GaN) power semiconductor devices. SiC power semiconductor devices are heat - resistant and have low power losses, and are suitable for electric vehicles, renewable energy systems, etc. GaN power semiconductor devices are expensive to manufacture, but are efficient in terms of speed and are suitable for high - speed charging of mobile devices. Summary of the invention

[0007] Embodiments of the inventive concept are directed to providing a semiconductor device having stable electrical characteristics and improved reliability.

[0008] A semiconductor device according to an embodiment includes a channel layer, a blocking layer, a source electrode and a drain electrode, a gate electrode, and a gate semiconductor layer. The blocking layer is located above the channel layer and includes a material having an energy bandgap different from that of the channel layer. The source electrode and the drain electrode are located on the channel layer. The gate electrode is located above the blocking layer between the source electrode and the drain electrode. The gate semiconductor layer is located between the blocking layer and the gate electrode. At the junction surface of the gate electrode and the gate semiconductor layer, the width of the gate electrode is smaller than the width of the gate semiconductor layer.

[0009] A semiconductor device according to an embodiment includes a channel layer, a blocking layer, a source electrode, a drain electrode, and a gate electrode. The channel layer includes GaN. The blocking layer is located above the channel layer and includes AlGaN. The source electrode and the drain electrode are located on the channel layer. The gate electrode is located above the blocking layer between the source electrode and the drain electrode and includes TiN. The ratio of the atomic percentage of Ti to the atomic percentage of N in the upper part of the gate electrode is lower than the ratio of the atomic percentage of Ti to the atomic percentage of N in the lower part of the gate electrode.

[0010] A semiconductor device according to an embodiment includes a channel layer, a blocking layer, a source electrode, a drain electrode, a gate electrode, and a gate semiconductor layer. The blocking layer is located above the channel layer and has a material with an energy bandgap different from that of the channel layer. The source electrode and the drain electrode are located on the channel layer. The gate electrode is located above the blocking layer between the source electrode and the drain electrode. The gate semiconductor layer is located between the blocking layer and the gate electrode. The width of the lower part of the gate electrode is smaller than the width of the upper part of the gate electrode. BRIEF DESCRIPTION OF THE DRAWINGS

[0011] Figure 1 and Figure 2 are cross-sectional views showing a semiconductor device according to an embodiment.

[0012] Figure 3 are cross-sectional views showing some layers of a semiconductor device according to an embodiment.

[0013] Figure 4 is a diagram showing the atomic percentages of materials of some layers constituting a semiconductor device according to an embodiment.

[0014] Figures 5 to 12 are cross-sectional views showing some layers of a semiconductor device according to an embodiment.

[0015] Figures 13 to 17 is a process cross-sectional view showing a semiconductor device according to an embodiment in the order of a manufacturing process.

[0016] Figure 18 are cross-sectional views showing a semiconductor device according to an embodiment.

[0017] Figure 19 are cross-sectional views showing a semiconductor device according to an embodiment.

[0018] Figure 20 are cross-sectional views showing a semiconductor device according to an embodiment.

[0019] Figures 21 to 27 is a process cross-sectional view showing a semiconductor device according to an embodiment in the order of a manufacturing process.

[0020] Figure 28 are cross-sectional views showing a semiconductor device according to an embodiment.

[0021] Figure 29 is a cross-sectional view showing a semiconductor device according to an embodiment.

[0022] Figure 30 is a cross-sectional view showing a semiconductor device according to an embodiment.

[0023] Figures 31 to 34 is a process cross-sectional view showing a semiconductor device according to an embodiment in the order of a manufacturing process.

[0024] Figure 35 is a cross-sectional view showing a semiconductor device according to an embodiment.

[0025] Figure 36 is a cross-sectional view showing a semiconductor device according to an embodiment. Detailed Description

[0026] The concept of the present invention will be described more fully hereinafter with reference to the accompanying drawings, in which embodiments of the invention are shown. However, the described embodiments can be modified in various different ways, all of which do not depart from the spirit or scope of the invention.

[0027] Throughout the specification, the same reference numerals denote the same elements.

[0028] In addition, although various dimensions and thicknesses of the constituent members are shown in the drawings, the concept of the present invention is not limited to the shown dimensions and thicknesses.

[0029] It will be understood that when an element such as a layer, film, region, or substrate is referred to as being "on" another element, it can be directly on the other element or intervening elements may also be present.

[0030] Hereinafter, with reference to Figures 1 to 4 a semiconductor device according to an embodiment will be described.

[0031] Figure 1 and Figure 2 is a cross-sectional view showing a semiconductor device according to an embodiment. Figure 1 represents a case where a semiconductor device according to an embodiment is in an off state. Figure 2 represents a case where a semiconductor device according to an embodiment is in an on state. For example, the semiconductor device may not receive sufficient power to operate during the off state and may receive sufficient power to operate during the on state. Figure 3 is a cross-sectional view showing some layers of a semiconductor device according to an embodiment. Figure 3 shows a gate semiconductor layer and a gate electrode of a semiconductor device according to an embodiment, and the remaining components are omitted. Figure 4It is a diagram showing the atomic percentages of the materials of some layers constituting a semiconductor device according to an embodiment. For example, in the embodiment, the atomic percentage of the material of the gate electrode constituting the semiconductor device.

[0032] As Figure 1 shown, a semiconductor device according to an embodiment includes a channel layer 132, a barrier layer 136 located on the channel layer 132, a gate electrode 155 located on the barrier layer 136, a gate semiconductor layer 152 located between the barrier layer 136 and the gate electrode 155, and source electrodes 173 and drain electrodes 175 spaced apart from each other on the channel layer 132.

[0033] The channel layer 132 is a layer that forms a channel between the source electrode 173 and the drain electrode 175. A two-dimensional electron gas (2DEG) 134 may be located inside the channel layer 132. The two-dimensional electron gas 134 is a charge transport model used in solid-state physics and refers to a group of electrons that can move freely in two dimensions (e.g., in the x-y plane direction) but cannot move in another dimension (e.g., the z direction) and are tightly bound within the two-dimensional space. In other words, the two-dimensional electron gas 134 can exist in a three-dimensional space in a two-dimensional paper-like form. This two-dimensional electron gas 134 mainly appears in semiconductor heterojunction structures and may appear at the interface between the channel layer 132 and the barrier layer 136 in the semiconductor device according to the embodiment. For example, the two-dimensional electron gas 134 may be generated in the portion of the channel layer 132 closest to the barrier layer 136.

[0034] The channel layer 132 may include one or more materials selected from III-V materials, such as nitrides of at least one of Al, Ga, In, and B. The channel layer 132 may be Al x In y Ga (1-x-y) N (0 ≤ x ≤ 1, 0 ≤ y ≤ 1, x + y ≤ 1). For example, the channel layer 132 may include at least one of AlN, GaN, InN, InGaN, AlGaN, AlInN, and AlInGaN. The channel layer 132 may be a layer doped with impurities or a layer without doped impurities. The thickness of the channel layer 132 may be about a few hundred nanometers (nm) or less.

[0035] The channel layer 132 may be located on the substrate 110, and the seed layer 115 and the buffer layer 120 may be located between the substrate 110 and the channel layer 132. The substrate 110, the seed layer 115, and the buffer layer 120 are layers for supporting the channel layer 132 and may be omitted in some cases. For example, when a substrate made of GaN is used as the channel layer 132, at least one of the substrate 110, the seed layer 115, and the buffer layer 120 may be omitted. Since the manufacturing cost of a substrate made of GaN is relatively high, a substrate 110 made of Si may be used to grow the channel layer 132. Since the lattice structure of Si is different from that of GaN, it may not be easy to directly grow the channel layer 132 on the substrate 110. Therefore, the seed layer 115 and the buffer layer 120 may be first grown on the substrate 110, and then the channel layer 132 may be grown on the buffer layer 120. In addition, after being used in the manufacturing process, at least one of the substrate 110, the seed layer 115, and the buffer layer 120 may be removed from the final structure of the semiconductor device.

[0036] The substrate 110 may include a semiconductor material. For example, the substrate 110 may include sapphire, Si, SiC, aluminum nitride (AlN), GaN, or a combination thereof. The substrate 110 may be a silicon-on-insulator (SOI) substrate. However, the material of the substrate 110 is not limited thereto, and any commonly used substrate may be applied. In some cases, the substrate 110 may include an insulating material. For example, after forming several layers including the channel layer 132 on a semiconductor substrate, the semiconductor substrate may then be removed and replaced with an insulating substrate.

[0037] The seed layer 115 may be located on the substrate 110. The seed layer 115 may be directly located on the substrate 110. However, it is not limited thereto, and another predetermined layer may also be located between the substrate 110 and the seed layer 115. The seed layer 115 is a layer that serves as a seed for growing the buffer layer 120 and may be made of a lattice structure that becomes the seed of the buffer layer 120. For example, the seed layer 115 may include AlN, but it is not limited thereto.

[0038] The buffer layer 120 may be located above the seed layer 115. For example, the buffer layer 120 may be directly located on the seed layer 115. However, it is not limited thereto, and another predetermined layer may be located between the seed layer 115 and the buffer layer 120. The buffer layer 120 may be located between the seed layer 115 and the channel layer 132. The buffer layer 120 may include one or more materials selected from III-V group materials, such as nitrides including at least one of Al, Ga, In, and B. The buffer layer 120 may be Al x In y Ga (1-x-y)N(0 ≤ x ≤ 1, 0 ≤ y ≤ 1, x + y ≤ 1). For example, the buffer layer 120 may include at least one of AlN, GaN, InN, InGaN, AlGaN, AlInN, and AlInGaN. The buffer layer 120 may be a single layer or multiple layers. The buffer layer 120 may include a superlattice layer 124 and a high-resistance layer 126 located on the superlattice layer 124. The high-resistance layer 126 may be located above the superlattice layer 124. At least one of the superlattice layer 124 and the high-resistance layer 126 may be omitted. In some cases, the buffer layer 120 may include not only the superlattice layer 124 and the high-resistance layer 126, but also other additional layers.

[0039] The superlattice layer 124 may be located above the seed layer 115. The superlattice layer 124 may be directly located on the seed layer 115. However, it is not limited thereto, and another predetermined layer may be located between the seed layer 115 and the superlattice layer 124. The superlattice layer 124 may be located between the substrate 110 and the channel layer 132. The superlattice layer 124 may reduce the difference in lattice constant and thermal expansion coefficient between the substrate 110 and the channel layer 132, thereby reducing the tensile stress and compressive stress generated between the substrate 110 and the channel layer 132. The superlattice layer 124 may release the compressive stress and release the stress between the entire layers formed by the growth in the final structure of the semiconductor device according to the embodiment. The superlattice layer 124 may include one or more materials selected from III-V materials, such as nitrides including at least one of Al, Ga, In, and B. The superlattice layer 124 may be Al x In y Ga (1-x-y) N(0 ≤ x ≤ 1, 0 ≤ y ≤ 1, x + y ≤ 1). For example, the superlattice layer 124 may include at least one of AlN, GaN, InN, InGaN, AlGaN, AlInN, and AlInGaN. The superlattice layer 124 may be a single layer or multiple layers. For example, the superlattice layer 124 may have a structure in which layers made of AlGaN and layers made of GaN are repeatedly stacked. For example, AlGaN / GaN / AlGaN / GaN / AlGaN / GaN may be sequentially stacked on the seed layer 115 to form the superlattice layer 124. However, the number of AlGaN layers and GaN constituting the superlattice layer 124 may be changed in various ways, and the materials constituting the superlattice layer 124 may be changed in various ways.

[0040] The high-resistance layer 126 may be located above the superlattice layer 124. For example, the high-resistance layer 126 may be directly located on the superlattice layer 124. However, it is not limited thereto, and other predetermined layers may be located between the superlattice layer 124 and the high-resistance layer 126. The high-resistance layer 126 may be located between the superlattice layer 124 and the channel layer 132. The high-resistance layer 126 is used to prevent the semiconductor device according to the embodiment from deteriorating by preventing parasitic current (leakage current) from flowing through the channel layer 132. The high-resistance layer 126 may be made of a material with low conductivity, so that the substrate 110 and the channel layer 132 are electrically insulated. For example, the material may be an insulator. The high-resistance layer 126 may include one or more materials selected from III-V materials, such as nitrides including at least one of Al, Ga, In, and B. The high-resistance layer 126 may be Al x In y Ga (1-x-y) N (0 ≤ x ≤ 1, 0 ≤ y ≤ 1, x + y ≤ 1). For example, the high-resistance layer 126 may include at least one of AlN, GaN, InN, InGaN, AlGaN, AlInN, and AlInGaN. The high-resistance layer 126 may be a single layer or multiple layers. The high-resistance layer 126 may be a layer without doping impurities. However, it is not limited thereto, and the high-resistance layer 126 may include impurities. For example, the high-resistance layer 126 may be doped with impurities made of carbon (C), magnesium (Mg), iron (Fe), or a combination thereof. In an embodiment, the impurity doping concentration of the high-resistance layer 126 is different from the impurity doping concentration of the channel layer 132.

[0041] The blocking layer 136 may be located above the channel layer 132. The blocking layer 136 may be directly located on the channel layer 132. However, it is not limited thereto, and another predetermined layer may also be located between the channel layer 132 and the blocking layer 136. The region of the channel layer 132 overlapping with the blocking layer 136 may be referred to as the drift region DTR. The drift region DTR may be located between the source electrode 173 and the drain electrode 175. When a potential difference appears between the source electrode 173 and the drain electrode 175, carriers may move into the drift region DTR. The semiconductor device according to the embodiment may be turned on / off according to whether a voltage is applied to the gate electrode 155 and / or the magnitude of the voltage applied to the gate electrode 155. When a voltage higher than the threshold voltage is applied to the gate electrode 155 to turn on the semiconductor device, a channel may be generated in the depletion region DPR. Therefore, the movement of carriers may occur in the drift region DTR. If a voltage lower than the threshold voltage is applied to the gate electrode 155 or no voltage is applied, the conduction path is blocked in the depletion region DPR, and the movement of carriers does not occur.

[0042] The blocking layer 136 may include one or more materials selected from III-V materials, such as nitrides including at least one of Al, Ga, In, and B. The blocking layer 136 may be Alx In y Ga (1-x-y) N (0 ≤ x ≤ 1, 0 ≤ y ≤ 1, x + y ≤ 1). The blocking layer 136 may include at least one of GaN, InN, AlGaN, AlInN, InGaN, AlN, AlInGaN, etc. The energy bandgap of the blocking layer 136 may be adjusted by the composition ratio of Al and / or In.

[0043] In an embodiment, the blocking layer 136 includes a semiconductor material having characteristics different from those of the channel layer 132 or is a semiconductor material having characteristics different from those of the channel layer 132. For example, the material of the blocking layer 136 may be different from the material of the channel layer 132. The blocking layer 136 may differ from the channel layer 132 in at least one of polarization characteristics, energy bandgap, and lattice constant. For example, the blocking layer 136 may include a material having an energy bandgap different from that of the channel layer 132. In an embodiment, the blocking layer 136 has a higher energy bandgap than the channel layer 132 and may have a higher electrode polarization rate than the channel layer 132. Due to the blocking layer 136, the two-dimensional electron gas 134 may be induced in the channel layer 132 having a relatively low electrode polarization rate. In this regard, the blocking layer 136 may also be referred to as a channel supply layer or a two-dimensional electron gas supply layer. The two-dimensional electron gas 134 may be formed in a portion of the channel layer 132 below the interface between the channel layer 132 and the blocking layer 136. The two-dimensional electron gas 134 may have a very high electron mobility.

[0044] The blocking layer 136 may be a single layer or multiple layers. If the blocking layer 136 is made of multiple layers, the energy bandgaps of the materials of each layer constituting the multiple layers may be different. In an embodiment, the multiple layers constituting the blocking layer 136 are arranged such that the energy bandgap increases as it approaches the channel layer 132. For example, the energy bandgap of a lower layer of the blocking layer 135 may be higher than the energy bandgap of a higher layer of the blocking layer 135 that is farther from the channel layer 132.

[0045] The gate electrode 155 may be located on the barrier layer 136. The gate electrode 155 may overlap some regions of the barrier layer 136. The gate electrode 155 may overlap a part of the drift region DTR of the channel layer 132. The gate electrode 155 may be located between the source electrode 173 and the drain electrode 175. The gate electrode 155 may be separated from the source electrode 173 and the drain electrode 175. In an embodiment, the gate electrode 155 is positioned closer to the source electrode 173 than the drain electrode 175. That is, the separation distance between the gate electrode 155 and the source electrode 173 may be smaller than the separation distance between the gate electrode 155 and the drain electrode 175. In an embodiment, the gate electrode 155 contacts the gate semiconductor layer 152. The bottom surface of the gate electrode 155 may contact the gate semiconductor layer 152. However, it is not limited thereto, and another predetermined layer may be located between the gate electrode 155 and the gate semiconductor layer 152.

[0046] The gate electrode 155 may include a conductive material. For example, the gate electrode 155 may include a metal, a metal alloy, a conductive metal nitride, a metal silicide, a doped semiconductor material, a conductive metal oxide, or a conductive metal oxynitride. For example, the gate electrode 155 may be a conductor. For example, the gate electrode 155 may include titanium nitride (TiN), tantalum carbide (TaC), tantalum nitride (TaN), titanium silicon nitride (TiSiN), tantalum silicon nitride (TaSiN), tantalum titanium nitride (TaTiN), titanium aluminum nitride (TiAlN), tantalum aluminum nitride (TaAlN), tungsten nitride (WN), ruthenium (Ru), titanium aluminum (TiAl), titanium aluminum carbonitride (TiAlC-N), titanium aluminum carbide (TiAlC), titanium carbide (TiC), tantalum carbonitride (TaCN), tungsten (W), aluminum (Al), copper (Cu), cobalt (Co), titanium (Ti), tantalum (Ta), nickel (Ni), platinum (Pt), nickel platinum (Ni-Pt), niobium (Nb), niobium nitride (NbN), niobium carbide (NbC), molybdenum (Mo), molybdenum nitride (MoN), molybdenum carbide (MoC), tungsten carbide (WC), rhodium (Rh), palladium (Pd), iridium (Ir), osmium (Os), silver (Ag), gold (Au), zinc (Zn), vanadium (V), or a combination thereof, but not limited thereto. The gate electrode 155 may be a single layer or a multi-layer.

[0047] The gate semiconductor layer 152 may be located between the barrier layer 136 and the gate electrode 155. That is, the gate semiconductor layer 152 may be located on the barrier layer 136, and the gate electrode 155 may be located on the gate semiconductor layer 152. The gate electrode 155 may make a Schottky contact with the gate semiconductor layer 152. However, it is not limited thereto, and in some cases, the gate electrode 155 may make an ohmic contact with the gate semiconductor layer 152. The gate semiconductor layer 152 may overlap the gate electrode 155 in the vertical direction. The vertical direction may represent a direction perpendicular to the upper surface of the channel layer 132 or the barrier layer 136.

[0048] The gate semiconductor layer 152 may be located between the source electrode 173 and the drain electrode 175. The gate semiconductor layer 152 may be separated from the source electrode 173 and the drain electrode 175. The gate semiconductor layer 152 may be positioned closer to the source electrode 173 than to the drain electrode 175. That is, the separation distance between the gate semiconductor layer 152 and the source electrode 173 may be less than the separation distance between the gate semiconductor layer 152 and the drain electrode 175.

[0049] The gate semiconductor layer 152 may include one or more materials selected from III-V group materials, such as nitrides including at least one of Al, Ga, In, and B. The gate semiconductor layer 152 may be Al x In y Ga (1-x-y) N (0 ≤ x ≤ 1, 0 ≤ y ≤ 1, x + y ≤ 1). For example, the gate semiconductor layer 152 may include at least one of AlN, GaN, InN, InGaN, AlGaN, AlInN, and AlInGaN. In an embodiment, the gate semiconductor layer 152 includes a material having an energy bandgap different from that of the blocking layer 136 or is a material having an energy bandgap different from that of the blocking layer 136. For example, the gate semiconductor layer 152 may include GaN, and the blocking layer 136 may include AlGaN. For example, in an embodiment, the blocking layer 136 includes AlGaN; and the gate semiconductor layer 152 includes GaN but does not include Al. The gate semiconductor layer 152 may be doped with a predetermined impurity. In an embodiment, the impurity doped in the gate semiconductor layer 152 is a P-type dopant capable of providing holes. For example, the gate semiconductor layer 152 may include GaN doped with a P-type impurity. That is, the gate semiconductor layer 152 may be made of a p-GaN layer. However, it is not limited thereto, and the gate semiconductor layer 152 may be a p-AlGaN layer. For example, the impurity doped in the gate semiconductor layer 152 may be magnesium (Mg). The gate semiconductor layer 152 may be a single layer or a multi-layer.

[0050] Hereinafter, with reference to Figure 3 and Figure 4 the shapes of the gate semiconductor layer 152 and the gate electrode 155 and the atomic percentages of the materials will be further described.

[0051] Further referring to Figure 3, the gate electrode 155 includes a groove gv that is recessed from the bottom surface and side surfaces of the gate electrode 155. At least a portion of the gate electrode 155 can be separated from the gate semiconductor layer 152 through the groove gv. The groove gv of the gate electrode 155 can include a curved surface. The groove gv can have a convex curved surface shape. Inside the groove gv, the slope of the side surface of the gate electrode 155 with respect to the gate semiconductor layer 152 can gradually increase as it approaches the gate semiconductor layer 152. For example, the slope of the side surface of the gate electrode 155 inside the groove gv can be in the range from about 0 degrees to about 90 degrees. In the region close to the gate semiconductor layer 152, the slope of the side surface of the gate electrode 155 can approach about 90 degrees. However, it is not limited thereto. For example, the shape of the groove gv can be changed in various ways. The width of the gate electrode 155 can gradually increase from the lower part to the upper part and then become constant. In an embodiment, the width Wth_b of the lower part of the gate electrode 155 is smaller than the width Wth_u of the upper part of the gate electrode 155. The width Wth_b of the lower part of the gate electrode 155 can be the minimum width of the gate electrode 155, and the width Wth_u of the upper part of the gate electrode 155 can be the maximum width of the gate electrode 155. The width of the gate semiconductor layer 152 can be almost constant. In an embodiment, the width of the lower part of the gate semiconductor layer 152 is the same as the width of the upper part of the gate semiconductor layer 152. The width Wth_b of the lower part of the gate electrode 155 can be smaller than the width of the gate semiconductor layer 152. In an embodiment, at the contact region between the gate electrode 155 and the gate semiconductor layer 152, the width of the gate electrode 155 is smaller than the width of the gate semiconductor layer 152. Therefore, at least a portion of the upper surface of the gate semiconductor layer 152 can be not covered by the gate electrode 155. Two edges of the upper surface of the gate semiconductor layer 152 can be not covered by the gate electrode 155. In an embodiment, the left edge of the gate semiconductor layer 152 and the right edge of the gate semiconductor layer 152 opposite to the left edge are not covered by the gate electrode 155. In an embodiment, the width Wth_u of the upper part of the gate electrode 155 is the same as or substantially the same as the width of the gate semiconductor layer 152. The gate semiconductor layer 152 can have a planar shape substantially the same as that of the upper part of the gate electrode 155.

[0052] In an embodiment, the depth dth of the groove gv of the gate electrode 155 corresponds to 1 / 2 of the difference between the width Wth_u of the upper portion of the gate electrode 155 and the width Wth_b of the lower portion. The depth dth of the groove gv of the gate electrode 155 can be greater than 0 and about 1 μm or less. In an embodiment, the depth dth of the groove gv of the gate electrode 155 is about 5 nm or greater and about 300 nm or less. The difference between the width Wth_u of the upper portion of the gate electrode 155 and the width Wth_b of the lower portion of the gate electrode 155 can be greater than 0 and less than or equal to about 1 μm, and in an embodiment, greater than or equal to about 5 nm and less than or equal to about 300 nm. The thickness Th (e.g., in the vertical direction) of the gate electrode 155 can be about or greater and about or less. In an embodiment, the thickness Th of the gate electrode 155 is about or greater and about or less.

[0053] With further reference to Figure 4 , the gate electrode 155 can include TiN. In an embodiment, the gate electrode 155 consists only of TiN. In Figure 4 , the horizontal axis represents the distance from the bottom surface of the gate electrode 155, and the vertical axis represents the atomic percentage of the material included in the gate electrode 155. The unit of the horizontal axis is omitted and can be determined according to the thickness of the gate electrode 155. The left end of the horizontal axis can indicate the bottom surface of the gate electrode 155, and the right end of the horizontal axis can indicate the upper surface of the gate electrode 155.

[0054] In an embodiment, the gate electrode 155 is made of a material including Ti and N. In an embodiment, as the distance from the bottom surface of the gate electrode 155 increases, the atomic percentage of Ti in the gate electrode 155 based on the total number of atoms in the gate electrode 155 decreases. As the distance from the gate semiconductor layer 152 increases, the atomic percentage of Ti in the gate electrode 155 based on the total number of atoms in the gate electrode 155 may tend to decrease. The atomic percentage of Ti in the gate electrode 155 may tend to decrease from the lower part to the upper part. The atomic percentage of Ti may be constant in at least a part of the gate electrode 155. For example, the atomic percentage of Ti in the gate electrode 155 may gradually decrease as the distance from the gate semiconductor layer 152 increases, and then be almost constant. The atomic percentage of N in the gate electrode 155 may tend to increase as the distance from the gate semiconductor layer 152 increases. The atomic percentage of N in the gate electrode 155 may tend to increase from the lower part to the upper part. In at least a part of the gate electrode 155, the atomic percentage of N in the gate electrode 155 based on the total number of atoms in the gate electrode 155 may be constant. For example, as the distance from the gate semiconductor layer 152 increases, the atomic percentage of N in the gate electrode 155 based on the total number of atoms in the gate electrode 155 may gradually increase, and then be almost constant.

[0055] In the lower part of the gate electrode 155, the atomic percentage of Ti may be about 40 atomic percent (at%) or more and about 60 at% or less.

[0056] In an embodiment, the atomic percentage of Ti in the lower part of the gate electrode 155 based on the total number of atoms in the gate electrode 155 is about 45 at% or more and about 55 at% or less. For example, the atomic percentage of Ti in the lower part of the gate electrode 155 based on the total number of atoms in the gate electrode 155 may be about 50 at%. The atomic percentage of N in the lower part of the gate electrode 155 based on the total number of atoms in the gate electrode 155 may be about 40 at% or more and about 60 at% or less. In an embodiment, the atomic percentage of N in the lower part of the gate electrode 155 based on the total number of atoms in the gate electrode 155 is about 45 at% or more and about 55 at% or less. For example, the atomic percentage of N in the lower part of the gate electrode 155 based on the total number of atoms in the gate electrode 155 may be about 50 at%. In the lower part of the gate electrode 155, the ratio of the atomic percentage of Ti to the atomic percentage of N may be about 0.67 or more and about 1.5 or less. In an embodiment, in the lower part of the gate electrode 155, the ratio of the atomic percentage of Ti to the atomic percentage of N is about 0.81 or more and about 1.22 or less. For example, in the lower part of the gate electrode 155, the ratio of the atomic percentage of Ti to the atomic percentage of N may be about 1. In other words, in the lower part of the gate electrode 155, the amount of Ti and the amount of N may be the same or very similar.

[0057] The atomic percentage of Ti in the upper portion of the gate electrode 155 based on the total number of atoms in the gate electrode 155 may be about 20 at% or greater and about 50 at% or less. In an embodiment, the atomic percentage of Ti in the upper portion of the gate electrode 155 based on the total number of atoms in the gate electrode 155 is about 35 at% or greater and about 45 at% or less. The atomic percentage of N in the upper portion of the gate electrode 155 based on the total number of atoms in the gate electrode 155 may be about 50 at% or greater and about 80 at% or less. In an embodiment, the atomic percentage of N in the upper portion of the gate electrode 155 based on the total number of atoms in the gate electrode 155 is about 50 at% or greater and about 60 at% or less. In the upper portion of the gate electrode 155, the ratio of the atomic percentage of Ti to the atomic percentage of N may be about 0.25 or greater and about 1 or less. In an embodiment, in the upper portion of the gate electrode 155, the ratio of the atomic percentage of Ti to the atomic percentage of N is about 0.58 or greater and about 0.9 or less. In the upper portion of the gate electrode 155, the amount of Ti may be lower than the amount of N.

[0058] Above, the case where the gate electrode 155 is made of a material including Ti and N has been described, but it is not limited thereto. The gate electrode 155 may further include other materials in addition to Ti and N. For example, the gate electrode 155 may further include O or C. Therefore, in the gate electrode 155, the ratio of the atomic percentage of Ti to the atomic percentage of N may also change.

[0059] Due to the gate semiconductor layer 152, a depletion region DPR may be formed in the channel layer 132. The depletion region DPR may be located within the drift region DTR and may have a narrower width than the drift region DTR. Since the gate semiconductor layer 152 having an energy bandgap different from that of the blocking layer 136 is located on the blocking layer 136, the energy level of the energy band of the portion of the blocking layer 136 overlapping with the gate semiconductor layer 152 may increase. Accordingly, a depletion region DPR may be formed in the region of the channel layer 132 overlapping with the gate semiconductor layer 152. The depletion region DPR may be a region in the conduction path of the channel layer 132 where no two-dimensional electron gas 134 is formed or where the electron concentration is lower than that in the remaining regions. In other words, the depletion region DPR may represent a region where the flow of the two-dimensional electron gas 134 is interrupted within the drift region DTR. When the depletion region DPR appears, current does not flow between the source electrode 173 and the drain electrode 175, and the conduction path may be blocked. Accordingly, the semiconductor device according to the embodiment may have normally-off characteristics.

[0060] That is, the semiconductor device according to the embodiment may be a normally-off type high electron mobility transistor (HEMT). As Figure 1As shown, in the normal state where no voltage is applied to the gate electrode 155, there is a depletion region DPR, and the semiconductor device according to the embodiment can be in an off state. As Figure 2 shown, when a voltage higher than the threshold voltage is applied to the gate electrode 155, the depletion region DPR disappears, and the two-dimensional electron gas 134 in the drift region DTR can be connected. That is, the two-dimensional electron gas 134 can be formed through the path between the source electrode 173 and the drain electrode 175, and the semiconductor device according to the embodiment can be turned on. In short, the semiconductor device according to the embodiment can include semiconductor layers with different polarization characteristics. For example, a semiconductor layer with a relatively high polarizability can induce a two-dimensional electron gas 134 in another semiconductor layer heterojunctioned therewith. This two-dimensional electron gas 134 can be used as a channel between the source electrode 173 and the drain electrode 175, and the connection or disconnection of the flow of this two-dimensional electron gas 134 can be controlled by the bias voltage applied to the gate electrode 155. In the gate-off state, the flow of the two-dimensional electron gas 134 is blocked, so current does not flow between the source electrode 173 and the drain electrode 175. Since the two-dimensional electron gas 134 continues to flow in the gate-on state, current can flow between the source electrode 173 and the drain electrode 175.

[0061] In the semiconductor device according to the embodiment, the width of the lower part of the gate electrode 155 is smaller than the width of the upper part of the gate electrode 155, and the width of the lower part of the gate electrode 155 is smaller than the width of the gate semiconductor layer 152. In the contact part between the gate electrode 155 and the gate semiconductor layer 152, the width of the gate electrode 155 can be smaller than the width of the gate semiconductor layer 152. Therefore, at least a part of the upper surface of the gate semiconductor layer 152 is not covered by the gate electrode 155, and there can be a part where the gate semiconductor layer 152 and the gate electrode 155 are spaced apart. In this way, the part of the gate semiconductor layer 152 that does not contact the gate electrode 155 can be used as a resistance component to increase the threshold voltage of the semiconductor device according to the embodiment. Therefore, the problem that the gate is not turned off or the reliability deteriorates due to the increase of the driving voltage or the increase of the ambient temperature caused by the lower threshold voltage can be solved.

[0062] As described above, the case where the semiconductor device according to the embodiment is a normally-off high electron mobility transistor has been described, but it is not limited thereto. For example, the semiconductor device according to the embodiment may be a normally-on high electron mobility transistor. In the case of a normally-on high electron mobility transistor, the gate semiconductor layer 152 may be omitted, and thus the gate electrode 155 may be directly located on the barrier layer 136. That is, the gate electrode 155 may be in contact with the barrier layer 136. In this structure, the two-dimensional electron gas 134 may be used as a channel without a voltage being applied to the gate electrode 155, and a current may occur between the source electrode 173 and the drain electrode 175. In addition, when a negative voltage is applied to the gate electrode 155, a depletion region DPR may occur, in which the flow of the two-dimensional electron gas 134 is interrupted under the gate electrode 155. In the semiconductor device according to the embodiment, since the width of the lower part of the gate electrode 155 is smaller than the width of the upper part, it can be used as a field dispersion layer for dispersing the electric field concentrated around the gate electrode 155. Therefore, the reliability of the semiconductor device can be ensured.

[0063] The above buffer layer 120, superlattice layer 124, high-resistance layer 126, channel layer 132, barrier layer 136, and gate semiconductor layer 152 may be sequentially stacked on the substrate 110. In the semiconductor device according to the embodiment, at least one of the buffer layer 120, superlattice layer 124, high-resistance layer 126, channel layer 132, barrier layer 136, and gate semiconductor layer 152 may be omitted. The buffer layer 120, superlattice layer 124, high-resistance layer 126, channel layer 132, barrier layer 136, and gate semiconductor layer 152 may be made of the same semiconductor-based material, and the material composition ratios of each layer may be different in consideration of the functions of each layer and the performance required for the semiconductor device.

[0064] The semiconductor device according to an embodiment may further include a first protective layer 140 located above the barrier layer 136 and the gate semiconductor layer 152. The first protective layer 140 may cover the upper surface of the barrier layer 136, and may cover the upper surface and side surfaces of the gate semiconductor layer 152. A portion of the gate semiconductor layer 152 not covered by the gate electrode 155 may be covered by the first protective layer 140. In addition, the first protective layer 140 may cover the upper surface and side surfaces of the gate electrode 155. The first protective layer 140 may be in contact with the barrier layer 136, the gate semiconductor layer 152, and the gate electrode 155. The barrier layer 136, the gate semiconductor layer 152, and the gate electrode 155 may be protected by the first protective layer 140 and may be separated from other components via the first protective layer 140. The first protective layer 140 may include an insulating material or insulator, or may be an insulating material or insulator. For example, the first protective layer 140 may include an oxide such as SiO2 or Al2O3. As another example, the first protective layer 140 may include a nitride such as SiN or a oxynitride such as SiON. The first protective layer 140 may be a single layer or multiple layers.

[0065] The source electrode 173 and the drain electrode 175 may be located above the channel layer 132. The source electrode 173 and the drain electrode 175 may be spaced apart from each other, and the gate electrode 155 and the gate semiconductor layer 152 may be located between the source electrode 173 and the drain electrode 175. The gate electrode 155 and the gate semiconductor layer 152 are spaced apart from the source electrode 173 and the drain electrode 175. The source electrode 173 may be electrically connected to the channel layer 132 on one side of the gate electrode 155. The drain electrode 175 may be electrically connected to the channel layer 132 on the other side of the gate electrode 155. In an embodiment, the source electrode 173 and the drain electrode 175 are located outside the drift region DTR of the channel layer 132. The interface between the source electrode 173 and the channel layer 132 may be one edge of the drift region DTR. Similarly, the interface between the drain electrode 175 and the channel layer 132 may be the other edge of the drift region DTR. However, the inventive concept is not limited thereto. For example, the source electrode 173 and / or the drain electrode 175 may be located within the drift region DTR of the channel layer 132. In an embodiment, the channel layer 132 is not recessed, and the source electrode 173 and the drain electrode 175 may be located on the upper surface of the channel layer 132. In an embodiment, the barrier layer 136 is not penetrated, and a part of the barrier layer 136 is recessed so that the source electrode 173 and the drain electrode 175 may be located on the upper surface of the barrier layer 136. The bottom surfaces of the source electrode 173 and the drain electrode 175 may be in contact with the upper surface of the channel layer 132. The portion of the channel layer 132 in contact with the source electrode 173 and the drain electrode 175 may be doped at a high concentration. At this time, carriers passing through the two-dimensional electron gas 134 may pass through the portion of the channel layer 132 doped at a high concentration, that is, the upper portion of the two-dimensional electron gas 134, and be transmitted to the source electrode 173 and the drain electrode 175. The source electrode 173 and the drain electrode 175 may not be in direct contact with the two-dimensional electron gas 134 in the horizontal direction. The horizontal direction may represent a direction parallel to the upper surface of the channel layer 132 or the barrier layer 136.

[0066] The source electrode 173 and the drain electrode 175 may be located above the first protective layer 140. Grooves that penetrate the first protective layer 140 and the barrier layer 136 and recess the upper surface of the channel layer 132 may be located on both sides of the gate electrode 155 and spaced apart from each other. The source electrode 173 and the drain electrode 175 may be respectively located in the grooves on both sides of the gate electrode 155. The source electrode 173 and the drain electrode 175 may be formed to fill the grooves. In the grooves, the source electrode 173 and the drain electrode 175 may be in contact with the channel layer 132 and the barrier layer 136. The channel layer 132 may form the bottom surface and the sidewalls of the grooves, and the barrier layer 136 may form the sidewalls of the grooves. Therefore, the source electrode 173 and the drain electrode 175 may be in contact with the upper surface and the side surfaces of the channel layer 132. In addition, the source electrode 173 and the drain electrode 175 may be in contact with the side surfaces of the barrier layer 136. That is, the source electrode 173 and the drain electrode 175 may cover the side surfaces of the channel layer 132 and the barrier layer 136. The upper surfaces of the source electrode 173 and the drain electrode 175 may protrude from the upper surface of the first protective layer 140. In some cases, at least one of the source electrode 173 and the drain electrode 175 may cover at least a portion of the upper surface of the first protective layer 140.

[0067] The source electrode 173 and the drain electrode 175 may include a conductive material or may be a conductor. For example, the source electrode 173 and the drain electrode 175 may include a metal, a metal alloy, a conductive metal nitride, a metal silicide, a doped semiconductor material, a conductive metal oxide, or a conductive metal oxynitride. For example, the source electrode 173 and the drain electrode 175 may include titanium nitride (TiN), tantalum carbide (TaC), tantalum nitride (TaN), titanium silicon nitride (TiSiN), tantalum silicon nitride (TaSiN), tantalum titanium nitride (TaTiN), titanium aluminum nitride (TiAlN), tantalum aluminum nitride (TaAlN), tungsten nitride (WN), ruthenium (Ru), titanium aluminum (TiAl), titanium aluminum carbonitride (TiAlC-N), titanium aluminum carbide (TiAlC), titanium carbide (TiC), tantalum carbonitride (TaCN), tungsten (W), aluminum (Al), copper (Cu), cobalt (Co), titanium (Ti), tantalum (Ta), nickel (Ni), platinum (Pt), nickel platinum (Ni-Pt), niobium (Nb), niobium nitride (NbN), niobium carbide (NbC), molybdenum (Mo), molybdenum nitride (MoN), molybdenum carbide (MoC), tungsten carbide (WC), rhodium (Rh), palladium (Pd), iridium (Ir), osmium (Os), silver (Ag), gold (Au), zinc (Zn), vanadium (V), or a combination thereof, but is not limited thereto. The source electrode 173 and the drain electrode 175 may be a single layer or a multi-layer. The source electrode 173 and the drain electrode 175 may have an ohmic contact with the channel layer 132. The regions in the channel layer 132 that are in contact with the source electrode 173 and the drain electrode 175 may be doped at a relatively high concentration compared to other regions.

[0068] The semiconductor device according to an embodiment may further include a field dispersion layer located above the first protective layer 140. The field dispersion layer may be located between the source electrode 173 and the drain electrode 175. The field dispersion layer may overlap the gate electrode 155 in the vertical direction. The gate electrode 155 may be covered by the field dispersion layer. The field dispersion layer may be electrically connected to the source electrode 173. The field dispersion layer may include the same material as the source electrode 173 and may be located in the same layer as the source electrode 173. The field dispersion layer may be formed simultaneously using the same process as the source electrode 173. The boundary between the field dispersion layer and the source electrode 173 may not be distinct, and thus the field dispersion layer may be formed integrally with the source electrode 173. However, this is not limited thereto, and the field dispersion layer may be a component separated from the source electrode 173. In addition, the field dispersion layer may be located in a layer different from the source electrode 173 and may be formed using a different process. In some cases, the field dispersion layer may be electrically connected to the gate electrode 155. For example, an opening overlapping the gate electrode 155 may be formed in the first protective layer 140, and the field dispersion layer may be connected to the gate electrode 155 through the opening. At this time, the field dispersion layer may not be connected to the source electrode 173.

[0069] The field dispersion layer may be used to disperse the electric field concentrated around the gate electrode 155. If a high voltage is applied to the drain electrode 175 in the gate-off state, the electric field may be concentrated around the gate electrode 155. If the electric field is concentrated on the gate electrode 155, the leakage current may increase and the breakdown voltage may decrease. The electric field concentrated around the gate electrode 155 may be dispersed by the field dispersion layer, thereby reducing the leakage current and increasing the breakdown voltage.

[0070] The cross-sectional shape of the gate electrode 155 of the semiconductor device according to an embodiment may be changed in various ways, and many exemplary variations of the shape of the gate electrode 155 are described with reference to Figures 5 to 12 FIG.

[0071] Figures 5 to 12 FIG. is a cross-sectional view showing some layers of the semiconductor device according to an embodiment. Figures 5 to 12 FIG. shows the gate semiconductor layer and the gate electrode of the semiconductor device according to an embodiment.

[0072] As Figure 5 shown, the gate electrode 155 of the semiconductor device according to an embodiment includes a groove gv. The groove gv may have a triangular cross-sectional shape. The inclined surface of the gate electrode 155 constituting the groove gv may have a predetermined inclination angle with respect to the upper surface of the gate semiconductor layer 152. In an embodiment, the inclination angle of the inclined surface of the gate electrode 155 is constant or an acute angle. That is, the gate electrode 155 may have an inverted conical shape. The width of the upper part of the gate electrode 155 may be constant, and starting from a predetermined point, the width of the gate electrode 155 may gradually decrease as it approaches the gate semiconductor layer 152. Figure 5The gate electrode 155 may include cross-sections of rectangular shape and trapezoidal shape.

[0073] As Figure 6 shown, the groove gv of the gate electrode 155 of the semiconductor device according to an embodiment has a square cross-section. The side surfaces of the gate electrode 155 constituting the groove gv may be perpendicular to the upper surface of the gate semiconductor layer 152. The gate electrode 155 may be divided into two parts according to the width. In an embodiment, the width of the lower part of the gate electrode 155 is smaller than the width of the upper part. The width of the lower part of the gate electrode 155 may be constant, and the width of the upper part may be constant. For example, Figure 6 the gate electrode 155 may include cross-sections of rectangular shape and square shape with a width smaller than the rectangular shape.

[0074] As Figure 7 shown, the groove gv of the gate electrode 155 of the semiconductor device according to an embodiment has a triangular cross-section. The gate electrode 155 may have an inverted conical shape. The width of the gate electrode 155 may gradually decrease from the upper part to the lower part. In other words, the width of the gate electrode 155 may gradually decrease as it approaches the gate semiconductor layer 152. The gate electrode 155 does not include a part with a constant width. Figure 7 the gate electrode 155 may include a trapezoidal cross-section.

[0075] As Figure 8 shown, the groove gv of the gate electrode 155 of the semiconductor device according to an embodiment includes a curved surface. The groove gv may have a concave curved surface shape. The slope of the side surface of the gate electrode 155 within the groove gv with respect to the gate semiconductor layer 152 may gradually decrease as the side surface of the gate electrode 155 approaches the gate semiconductor layer 152. For example, the slope of the side surface of the gate electrode 155 within the groove gv may be in the range of about 90 degrees to about 0 degrees. In the region close to the gate semiconductor layer 152, the slope of the side surface of the gate electrode 155 may approach 0 degrees.

[0076] As Figure 9 shown, the groove gv of the gate electrode 155 of the semiconductor device according to an embodiment has one or more stepped shapes. The surface of the gate electrode 155 constituting the groove gv may have a stepped shape. The width of the upper part of the gate electrode 155 may be constant, and starting from a predetermined point, the width of the gate electrode 155 may gradually decrease in stages as it approaches the gate semiconductor layer 152. The number of stages of the width reduction of the gate electrode 155 may vary. In addition, the thickness of the gate electrode 155 corresponding to each stage may be constant, or the thickness of the gate electrode 155 may be different in at least some stages.

[0077] As Figure 10 and Figure 11As shown, the groove gv of the gate electrode 155 of the semiconductor device according to the embodiment has an approximately stepped shape. At this time, each step may have a convex curved surface shape or a concave curved surface shape. The width of the upper part of the gate electrode 155 may be constant, and starting from a predetermined point, the width of the gate electrode 155 gradually decreases in stages as it approaches the gate semiconductor layer 152. However, within each step, the width of the gate electrode 155 may gradually decrease.

[0078] As Figure 12 shown, the groove gv of the gate electrode 155 of the semiconductor device according to the embodiment includes a curved surface. In the foregoing embodiment, the point where the width of the gate electrode 155 is the smallest may be the portion in contact with the gate semiconductor layer 152. In the present embodiment, the width of the portion of the gate electrode 155 in contact with the gate semiconductor layer 152 may not be the smallest. The point where the width of the gate electrode 155 is the smallest may be the portion at a predetermined distance from the gate semiconductor layer 152. The width of the upper part of the gate electrode 155 may be constant, and starting from a predetermined point, the width of the gate electrode 155 may decrease as it approaches the gate semiconductor layer 152 and then increase again. In the embodiment, the width of the gate electrode 155 in contact with the gate semiconductor layer 152 is smaller than the width of the gate semiconductor layer 152.

[0079] Above, various cross-sectional shapes of the gate electrode of the semiconductor device according to the embodiment have been described, but they are not limited thereto.

[0080] Next, refer to Figures 13 to 17 to describe a method of manufacturing a semiconductor device according to the embodiment.

[0081] Figures 13 to 17 is a process cross-sectional view of a semiconductor device according to the embodiment shown in the order of the manufacturing process.

[0082] First, as Figure 13 shown, a seed layer 115, a buffer layer 120, a channel layer 132, a barrier layer 136, a gate semiconductor material layer 152a, and a gate electrode material layer 155a are sequentially formed on a substrate 110.

[0083] The substrate 110 may include a semiconductor material or may be a semiconductor material. For example, the substrate 110 may include sapphire, Si, SiC, AlN, GaN, or a combination thereof. The substrate 110 may be a silicon-on-insulator (SOI) substrate. However, the material of the substrate 110 is not limited thereto, and any commonly used substrate may be applied.

[0084] The seed layer 115, buffer layer 120, channel layer 132, blocking layer 136, and gate semiconductor material layer 152a can be sequentially formed using an epitaxial growth method. The seed layer 115 can be first formed on the substrate 110, and the buffer layer 120 can be formed on the seed layer 115. The buffer layer 120 can include a superlattice layer 124 and a high-resistance layer 126. The channel layer 132 can be formed on the buffer layer 120, the blocking layer 136 can be formed on the channel layer 132, and the gate semiconductor material layer 152a can be formed on the blocking layer 136.

[0085] The seed layer 115, buffer layer 120, channel layer 132, blocking layer 136, and gate semiconductor material layer 152a can be made of the same semiconductor-based material. However, considering the function of each layer and the performance required for the semiconductor device, the material composition ratios of each layer can be different. The seed layer 115, buffer layer 120, channel layer 132, blocking layer 136, and gate semiconductor material layer 152a can include one or more materials selected from III-V materials, for example, nitrides of at least one of Al, Ga, In, and B. The seed layer 115, buffer layer 120, channel layer 132, blocking layer 136, and gate semiconductor material layer 152a can be Al x In y Ga (1-x-y) N (0 ≤ x ≤ 1, 0 ≤ y ≤ 1, x + y ≤ 1). The seed layer 115, buffer layer 120, channel layer 132, blocking layer 136, and gate semiconductor material layer 152a can include at least one of AlN, GaN, InN, InGaN, AlGaN, AlInN, and AlInGaN. The blocking layer 136 can include a material having an energy bandgap different from that of the channel layer 132. The blocking layer 136 can have a higher energy bandgap than the channel layer 132. The gate semiconductor material layer 152a can include a material having an energy bandgap different from that of the blocking layer 136.

[0086] As an example, the substrate 110 includes Si, the seed layer 115 includes AlN, and the superlattice layer 124 can have a structure in which layers made of AlGaN and layers made of GaN are repeatedly stacked. The high-resistance layer 126 can include GaN or can be GaN, the channel layer 132 can include GaN or can be GaN, and the blocking layer 136 can include AlGaN or can be AlGaN. The channel layer 132 and the blocking layer 136 may or may not be impurity-doped. The gate semiconductor material layer 152a can include GaN or can be GaN, and can be doped with impurities. The gate semiconductor material layer 152a can be doped with a p-type impurity, for example, magnesium (Mg).

[0087] Since the lattice structures of Si and GaN are different, it may not be easy to directly grow the channel layer 132 made of GaN on the substrate 110 made of Si. In the method of manufacturing a semiconductor device according to an embodiment, first, a seed layer 115 and a buffer layer 120 are formed on the substrate 110, and then the channel layer 132 is formed so that the lattice structure of the channel layer 132 can be stably formed.

[0088] Subsequently, a gate electrode material layer 155a may be formed on the gate semiconductor material layer 152a. The gate semiconductor material layer 152a is located between the blocking layer 136 and the gate electrode material layer 155a.

[0089] The gate electrode material layer 155a may be formed using a deposition process. For example, at least one of physical vapor deposition (PVD), thermal chemical vapor deposition (thermal CVD), low-pressure chemical vapor deposition (LP-CVD), plasma-enhanced chemical vapor deposition (PE-CVD), or atomic layer deposition (ALD) techniques may be used to form the gate electrode material layer 155a, but it is not limited thereto.

[0090] The gate electrode material layer 155a may include a conductive material or may be a conductive material, or may be a conductor. For example, the gate electrode material layer 155a may include a metal, a metal alloy, a conductive metal nitride, a metal silicide, a doped semiconductor material, a conductive metal oxide, or a conductive metal oxynitride, etc. For example, the gate electrode material layer 155a may include titanium nitride (TiN), tantalum carbide (TaC), tantalum nitride (TaN), titanium silicon nitride (TiSiN), tantalum silicon nitride (TaSiN), tantalum titanium nitride (TaTiN), titanium aluminum nitride (TiAlN), tantalum aluminum nitride (TaAlN), tungsten nitride (WN), ruthenium (Ru), titanium aluminum (TiAl), titanium aluminum carbonitride (TiAlC-N), titanium aluminum carbide (TiAlC), titanium carbide (TiC), tantalum carbonitride (TaCN), tungsten (W), aluminum (Al), copper (Cu), cobalt (Co), titanium (Ti), tantalum (Ta), nickel (Ni), platinum (Pt), nickel platinum (Ni-Pt), niobium (Nb), niobium nitride (NbN), niobium carbide (NbC), molybdenum (Mo), molybdenum nitride (MoN), molybdenum carbide (MoC), tungsten carbide (WC), rhodium (Rh), palladium (Pd), iridium (Ir), osmium (Os), silver (Ag), gold (Au), zinc (Zn), vanadium (V), or a combination thereof, but it is not limited thereto. The gate electrode material layer 155a may be a single layer or a multi-layer.

[0091] Within the gate electrode material layer 155a, the atomic percentages of the materials constituting the gate electrode material layer 155a may vary according to position. The atomic percentages of the materials constituting the gate electrode material layer 155a may vary according to the distance from the gate semiconductor material layer 152a. For example, the gate electrode material layer 155a may include TiN, and in the gate electrode material layer 155a, the atomic percentage of Ti and the atomic percentage of N may be different according to the distance from the gate semiconductor material layer 152a. The atomic percentage of Ti in the gate electrode material layer 155a based on the total number of atoms in the gate electrode material layer 155a may tend to decrease as the distance from the gate semiconductor material layer 152a increases. The atomic percentage of Ti in the gate electrode material layer 155a based on the total number of atoms in the gate electrode material layer 155a may tend to decrease from the lower part to the upper part. In at least some regions of the gate electrode material layer 155a, the atomic percentage of Ti in the gate electrode material layer 155a based on the total number of atoms in the gate electrode material layer 155a may be constant. For example, the atomic percentage of Ti in the gate electrode material layer 155a may gradually decrease as it moves away from the gate semiconductor material layer 152a, and then remain constant or substantially constant. The atomic percentage of Ti in the lower part of the gate electrode material layer 155a based on the total number of atoms in the gate electrode material layer 155a may be about 40 at% or greater and about 60 at% or less, and gradually decrease as it moves away from the gate semiconductor material layer 152a, such that the atomic percentage of Ti in the upper part of the gate electrode material layer 155a based on the total number of atoms in the gate electrode material layer 155a may be about 20 at% or greater and about 50 at% or less. The atomic percentage of N in the gate electrode material layer 155a based on the total number of atoms in the gate electrode material layer 155a may tend to increase as it moves away from the gate semiconductor material layer 152a. The atomic percentage of N in the gate electrode material layer 155a based on the total number of atoms in the gate electrode material layer 155a may tend to increase from the lower part to the upper part. In at least some regions of the gate electrode material layer 155a, the atomic percentage of N in the gate electrode material layer 155a based on the total number of atoms in the gate electrode material layer 155a may be constant. For example, the atomic percentage of N in the gate electrode material layer 155a based on the total number of atoms in the gate electrode material layer 155a may gradually increase as it moves away from the gate semiconductor material layer 152a, and then remain constant or substantially constant. The atomic percentage of N in the lower part of the gate electrode material layer 155a based on the total number of atoms in the gate electrode material layer 155a may be about 40 at% or greater and about 60 at% or less, and gradually increase as it moves away from the gate semiconductor material layer 152a, such that the atomic percentage of N in the upper part of the gate electrode material layer 155a based on the total number of atoms in the gate electrode material layer 155a may be about 50 at% or greater and about 80 at% or less.In the process of forming the gate electrode material layer 155a, the atomic percentage of the material constituting the gate electrode material layer 155a can be changed by controlling the flow rate of nitrogen gas (N2). For example, in the process of forming the gate electrode material layer 155a, the flow rate of N2 gas can be gradually increased.

[0092] Then, by patterning the gate electrode material layer 155a, as Figure 14 shown, the gate electrode 155 can be formed. At this time, a dry etching process or a wet etching process can be used to pattern the gate electrode material layer 155a.

[0093] In the etching process, portions having different composition ratios of the material constituting the gate electrode material layer 155a can have different etching rates. For example, the larger the atomic percentage of Ti, the higher the etching rate, and the larger the atomic percentage of N, the smaller the etching rate. In an embodiment, from the lower part to the upper part of the gate electrode material layer 155a, the atomic percentage of Ti can decrease, and the atomic percentage of N can increase. Therefore, the etching rates of the lower and upper parts of the gate electrode material layer 155a can be different. For example, the etching rate of the lower part of the gate electrode material layer 155a can be greater than that of the upper part. In other words, if the etching is performed for the same amount of time, the lower part of the gate electrode material layer 155a can be etched more relative to the upper part.

[0094] Due to these etching characteristics, the width of the lower part of the gate electrode 155 can be relatively smaller than that of the upper part. In addition, by over-etching, changing the conditions of the etching gas, adjusting the bias voltage, etc., the difference between the width of the lower part of the gate electrode 155 and the width of the upper part of the gate electrode 155 can be made larger. The width of the gate electrode 155 can gradually increase from the lower part to the upper part and then become constant. The gate electrode 155 can include a groove gv that is recessed from the bottom surface and the side surface. The shape of the groove gv of the gate electrode 155 can be changed in various ways as described above. Depending on the type, composition ratio, etching process conditions, etc. of the material constituting the gate electrode material layer 155a, the shape of the groove gv can be formed in various ways.

[0095] Then, by patterning the Figure 14 gate semiconductor material layer 152a, as Figure 15 shown, the gate semiconductor layer 152 can be formed. At this time, a dry etching process can be used to pattern the gate semiconductor material layer 152a. The gate semiconductor layer 152 is located between the barrier layer 136 and the gate electrode 155. The gate electrode 155 can have a Schottky contact or an ohmic contact with the gate semiconductor layer 152.

[0096] In order to minimize the damage to the barrier layer 136 during the process of etching the gate semiconductor material layer 152a, selective etching process conditions with a difference in the etching rates of the gate semiconductor material layer 152a and the barrier layer 136 can be used. For example, while the barrier layer 136 made of AlGaN is hardly etched, the gate semiconductor material layer 152a made of p-GaN can be easily etched. At this time, a surface oxidation etching method can be used by adding oxygen (O2) to the etching gas. Therefore, if the barrier layer 136 is not damaged and has a predetermined thickness, the channel layer 132 can have a high current density.

[0097] The gate semiconductor material layer 152a can be patterned using the hard mask pattern remaining on the gate electrode 155 or the gate electrode 155. Therefore, the gate semiconductor layer 152 can have a pattern similar to that of the gate electrode 155. That is, the gate semiconductor layer 152 and the gate electrode 155 can have substantially the same planar shape. In cross-section, the width of the gate semiconductor layer 152 can be substantially the same as the maximum width of the gate electrode 155, but is not limited thereto, and the width of the gate semiconductor layer 152 can be less than or equal to the maximum width of the gate electrode 155. The width of the gate semiconductor layer 152 can be substantially the same as the width of the upper part of the gate electrode 155, but is not limited thereto. For example, the width of the gate semiconductor layer 152 can be less than or equal to the width of the upper part of the gate electrode 155. The width of the gate semiconductor layer 152 is shown as constant, but is not limited thereto, and can have a normal tapered shape in some cases.

[0098] In the semiconductor device according to the embodiment, the width of the lower part of the gate electrode 155 is less than the width of the upper part of the gate electrode 155, and the width of the lower part of the gate electrode 155 is less than the width of the gate semiconductor layer 152. In the contact portion between the gate electrode 155 and the gate semiconductor layer 152, the width of the gate electrode 155 can be less than the width of the gate semiconductor layer 152. Therefore, at least a part of the upper surface of the gate semiconductor layer 152 can be not covered by the gate electrode 155, and there can be a part where the gate semiconductor layer 152 and the gate electrode 155 are spaced apart. In this way, the part of the gate semiconductor layer 152 that does not contact the gate electrode 155 can be used as a resistance component, thereby increasing the threshold voltage of the semiconductor device according to the embodiment. Therefore, the problem of the gate not being cut off or the reliability deteriorating when the threshold voltage is low due to an increase in the driving voltage or an increase in the ambient temperature can be solved.

[0099] As Figure 16 shown, a first protective layer 140 can be formed on the barrier layer 136, the gate semiconductor layer 152, and the gate electrode 155.

[0100] The first protective layer 140 may be formed using a deposition process. The first protective layer 140 may include an insulating material or insulator, or may be an insulating material or insulator. For example, the first protective layer 140 may include materials such as SiO2, SiN, SiON, Al2O3, etc. The first protective layer 140 is shown as a single layer, but in some embodiments, it may include multiple layers. At this time, different materials may be sequentially deposited to form the first protective layer 140. Alternatively, by using the same material and changing the deposition conditions, the first protective layer 140 composed of several layers with different characteristics may be formed. The portion of the first protective layer 140 adjacent to the blocking layer 136 may be made of an insulating material of much better quality than other portions. This is to prevent electrons forming a channel from being trapped in the channel layer 132 located below the blocking layer 136. For example, the portion of the first protective layer 140 in contact with the blocking layer 136 may be made of SiO2.

[0101] The upper surface of the blocking layer 136 may be covered by the first protective layer 140. The upper surface and side surfaces of the gate semiconductor layer 152 may be covered by the first protective layer 140. The portion of the gate semiconductor layer 152 not covered by the gate electrode 155 (i.e., the edge of the upper surface of the gate semiconductor layer 152) may be covered by the first protective layer 140. The upper surface and side surfaces of the gate electrode 155 may be covered by the first protective layer 140. The groove gv of the gate electrode 155 may be filled with the first protective layer 140. There may be a step between the portion of the first protective layer 140 overlapping with the gate electrode 155 and the gate semiconductor layer 152 and the remaining portion. However, it is not limited thereto, and in some embodiments, the upper surface of the first protective layer 140 may be completely flat. For example, if the thickness of the first protective layer 140 is relatively thick, there should be no step between the portion of the first protective layer 140 overlapping with the gate electrode 155 and the gate semiconductor layer 152 and the remaining portion. In this embodiment, the first protective layer 140 may have a uniform thickness.

[0102] As Figure 17 shown, by patterning the first protective layer 140, the first trench 141 and the second trench 143 may be formed. At this time, not only the first protective layer 140 but also the blocking layer 136 and the channel layer 132 may be patterned together.

[0103] For example, a photoresist pattern may be formed on the first protective layer 140, and the first protective layer 140, the barrier layer 136, and the channel layer 132 may be sequentially etched using the photoresist pattern as a mask. At this time, the first protective layer 140 and the barrier layer 136 may be penetrated by the first trench 141 and the second trench 143, and the upper surface of the channel layer 132 may be recessed. The channel layer 132 does not need to be penetrated by the first trench 141 or the second trench 143. That is, the depth of the recess of the upper surface of the channel layer 132 may be less than the entire thickness of the channel layer 132. At this time, the depth of the recess of the upper surface of the channel layer 132 may be much smaller than the entire thickness of the channel layer 132. For example, the depth of the recess of the upper surface of the channel layer 132 may be about 0% to about 30% of the entire thickness of the channel layer 132. In addition, the depth of the recess of the upper surface of the channel layer 132 may be less than the thickness of the barrier layer 136. However, it is not limited thereto, and the depth of the recess of the upper surface of the channel layer 132 may vary, and in some embodiments, the upper surface of the channel layer 132 does not need to be recessed. The side surfaces of the first protective layer 140 and the barrier layer 136 may be exposed to the outside through the first trench 141 and the second trench 143, and the top surface and the side surfaces of the channel layer 132 may be exposed. The channel layer 132 may form the bottom surface and the side walls of the first trench 141 and the second trench 143, and the barrier layer 136 may form the side walls of the first trench 141 and the second trench 143.

[0104] The first trench 141 and the second trench 143 may be spaced apart from each other. The first trench 141 may be located on one side (e.g., the left side) of the gate electrode 155, and the second trench 143 may be located on the other side (e.g., the right side) of the gate electrode 155. The first trench 141 may be located on one side (e.g., the left side) of the gate electrode 155 to be spaced apart from the gate electrode 155. The second trench 143 may be located on the other side (e.g., the right side) of the gate electrode 155 to be spaced apart from the gate electrode 155. The distance by which the first trench 141 is separated from the gate electrode 155 may be less than the distance by which the second trench 143 is separated from the gate electrode 155. The shapes such as the width and the depth of the first trench 141 and the second trench 143 are shown to be similar, but it is not limited thereto. The shapes of the first trench 141 and the second trench 143 may be changed in various ways.

[0105] Next, a conductive material or a conductor is deposited on the first protective layer 140 on which the first trench 141 and the second trench 143 are formed, and is patterned to form the source electrode 173 and the drain electrode 175.

[0106] The source electrode 173 and the drain electrode 175 may include a conductive material or may be a conductor. For example, the source electrode 173 and the drain electrode 175 may include a metal, a metal alloy, a conductive metal nitride, a metal silicide, a doped semiconductor material, a conductive metal oxide, or a conductive metal oxynitride. The source electrode 173 and the drain electrode 175 may be a single layer or a multi-layer. For example, a plurality of conductive layers including different materials may be stacked, and then the plurality of conductive layers may be patterned to form the source electrode 173 and the drain electrode 175. At this time, a single mask pattern may be used to etch the plurality of conductive layers simultaneously or sequentially.

[0107] The source electrode 173 may be formed to fill the inside of the first trench 141. Inside the first trench 141, the source electrode 173 may be in contact with the channel layer 132 and the blocking layer 136. The source electrode 173 may be in contact with the side surfaces of the channel layer 132 and the blocking layer 136. The source electrode 173 may cover the side surfaces of the channel layer 132 and the blocking layer 136. The source electrode 173 may be electrically connected to the channel layer 132 through the first trench 141. The upper surface of the source electrode 173 may protrude from the upper surface of the first protective layer 140.

[0108] The drain electrode 175 may be formed to fill the inside of the second trench 143. Inside the second trench 143, the drain electrode 175 may be in contact with the channel layer 132 and the blocking layer 136. The drain electrode 175 may be in contact with the side surfaces of the channel layer 132 and the blocking layer 136. The drain electrode 175 may cover the side surfaces of the channel layer 132 and the blocking layer 136. The drain electrode 175 may be electrically connected to the channel layer 132 through the second trench 143. The upper surface of the drain electrode 175 may protrude from the upper surface of the first protective layer 140.

[0109] The source electrode 173 and the drain electrode 175 may be in ohmic contact with the channel layer 132. The region of the channel layer 132 in contact with the source electrode 173 and the drain electrode 175 may be doped at a relatively high concentration compared to other regions. For example, the channel layer 132 may be doped by an ion implantation process or an annealing process. However, the present invention is not limited thereto, and the doping process of the channel layer 132 may include various other processes. The doping process of the channel layer 132 may be performed before forming the source electrode 173 and the drain electrode 175. In some embodiments, the channel layer 132 is not doped.

[0110] Inside the channel layer 132, a two-dimensional electron gas 134 may be formed in a portion adjacent to the blocking layer 136. The two-dimensional electron gas 134 may be located at the interface between the channel layer 132 and the blocking layer 136. The two-dimensional electron gas 134 may be located in the drift region DTR between the source electrode 173 and the drain electrode 175. A depletion region DPR may be formed in the channel layer 132 by a gate semiconductor layer 152 having an energy bandgap different from that of the blocking layer 136. Accordingly, the semiconductor device according to the embodiment may have normally-off characteristics. That is, the semiconductor device according to the embodiment may be a normally-off type high electron mobility transistor (HEMT). In the gate-off state, the two-dimensional electron gas 134 can be located in the drift region DTR except for the depletion region DPR of the channel layer 132. In the gate-on state, the flow of the two-dimensional electron gas 134 is continuous in the depletion region DPR, allowing the two-dimensional electron gas 134 to be entirely located in the drift region DTR.

[0111] Next, refer to Figure 18 to describe a semiconductor device according to an embodiment.

[0112] Figure 18 is a cross-sectional view showing a semiconductor device according to an embodiment.

[0113] Figure 18 Many parts of the embodiment shown in Figure 1 are the same as the embodiment shown in Figure 18 and thus the description thereof will be omitted, and the differences will be mainly described. In addition, the same reference numerals are used for components that are the same as those in the previous embodiment.

[0114] As Figure 18 shown, the gate electrode 155 of the semiconductor device according to the embodiment includes a groove gv.

[0115] In the previous embodiment, the grooves gv are located on both edges of the gate electrode 155, while in this embodiment, the grooves gv are located only on one edge of the gate electrode 155. For example, the grooves gv may be located only on the right edge among the left and right edges of the gate electrode 155. At this time, the left edge of the gate electrode 155 may be adjacent to the source electrode 173, and the right edge of the gate electrode 155 may be adjacent to the drain electrode 175. That is, the grooves gv may be formed at the edge of the gate electrode 155 adjacent to the drain electrode 175. In this embodiment, the grooves gv are not formed at the edge of the gate electrode 155 adjacent to the source electrode 173. Since the grooves gv are formed in the portion of the gate electrode 155 adjacent to the drain electrode 175 that receives a relatively high voltage, the electric field concentrated around the gate electrode 155 can be dispersed. However, this is not limited thereto, and the grooves gv may be formed at the edge of the gate electrode 155 adjacent to the source electrode 173. The shape of the grooves gv of the gate electrode 155 can be changed in various ways as described above. In cross-section, the width of the upper part of the gate electrode 155 and the width of the semiconductor layer 152 are shown to be the same, but this is not limited thereto, and the width of the upper part of the gate electrode 155 may be greater than the width of the semiconductor layer 152 and may extend to overlap the drift region DTR located outside the depletion region DPR in the vertical direction.

[0116] Next, refer to Figure 19 to describe the semiconductor device according to an embodiment.

[0117] Figure 19 is a cross-sectional view showing the semiconductor device according to an embodiment.

[0118] Figure 19 Many parts of the embodiment shown in Figure 1 are the same as those of the embodiment shown in Figure 1 , so any redundant description thereof will be omitted, and the differences will be mainly described. In addition, the same reference numerals are used for the same components as in the previous embodiment. Figure 19 The slight difference between the embodiment shown in Figure 19 and the previous embodiment is that the gate semiconductor layer is omitted.

[0119] As Figure 19 shown, the semiconductor device according to an embodiment includes a channel layer 132, a blocking layer 136 located on the channel layer 132, a gate electrode 155 located on the blocking layer 136, and a source electrode 173 and a drain electrode 175 spaced apart from each other on the channel layer 132.

[0120] In a previous embodiment, the gate semiconductor layer was located between the blocking layer 136 and the gate electrode 155. However, in this embodiment, the gate semiconductor layer is not located between the blocking layer 136 and the gate electrode 155. For example, the gate semiconductor layer is omitted. The gate electrode 155 may be directly located on the blocking layer 136. The bottom surface of the gate electrode 155 may be in contact with the upper surface of the blocking layer 136. However, it is not limited thereto, and a capping layer may be located between the blocking layer 136 and the gate electrode 155. The capping layer may include GaN or may be GaN, and may have a thickness of several nm. The two-dimensional electron gas 134 may be used as a channel without a voltage being applied to the gate electrode 155, and current may occur between the source electrode 173 and the drain electrode 175. The semiconductor device according to this embodiment may be a normally-on high electron mobility transistor.

[0121] The gate electrode 155 of the semiconductor device according to the embodiment includes at least one groove gv, and the shape of the groove gv may be changed in various ways as described above. At least a part of the gate electrode 155 may be separated from the blocking layer 136 through the groove gv. The shape of the gate electrode 155 may help control the electric field concentrated on the edge of the gate electrode 155, thereby improving the reliability of the semiconductor device.

[0122] Next, refer to Figure 20 to describe the semiconductor device according to the embodiment.

[0123] Figure 20 is a cross-sectional view showing the semiconductor device according to the embodiment.

[0124] Figure 20 Many parts of the embodiment shown in Figure 1 are the same as the embodiment shown in Figure 20 Therefore, any redundant description thereof will be omitted, and the differences will be mainly described. In addition, the same reference numerals are used for the same components as in the previous embodiment. Figure 20 The slight difference between the embodiment shown in

[0125] and the previous embodiment is that the first protective layer includes a first lower protective layer and a first upper protective layer. Figure 20 As Figure 20 shown, the first protective layer 140 is located on the blocking layer 136 and the gate semiconductor layer 152. The first protective layer 140 includes a first lower protective layer 140a and a first upper protective layer 140b. The first upper protective layer 140b is located above the first lower protective layer 140a.

[0126] The first lower protection layer 140a may cover the upper surface of the barrier layer 136, the upper surface and the side surfaces of the gate semiconductor layer 152. The portion of the gate semiconductor layer 152 not covered by the gate electrode 155 may be covered by the first lower protection layer 140a. In addition, the first lower protection layer 140a may cover a part of the side surface of the gate electrode 155. The first lower protection layer 140a may be in contact with the barrier layer 136, the gate semiconductor layer 152, and the gate electrode 155. The gate electrode 155 includes at least one groove gv, and the groove gv of the gate electrode 155 is filled with the first lower protection layer 140a. In the region where the gate electrode 155 and the gate semiconductor layer 152 are separated, the first lower protection layer 140a may be located between the gate electrode 155 and the gate semiconductor layer 152.

[0127] The first upper protection layer 140b is located above the first lower protection layer 140a and the gate electrode 155. The first upper protection layer 140b may cover a part of the side surface and the upper surface of the gate electrode 155. The first upper protection layer 140b may be in contact with the first lower protection layer 140a and the gate electrode 155. The first upper protection layer 140b is not in contact with the barrier layer 136 and the gate semiconductor layer 152. The first lower protection layer 140a may be located between the barrier layer 136 and the first upper protection layer 140b.

[0128] The side surfaces of the first lower protection layer 140a and the first upper protection layer 140b may be in contact with the source electrode 173. In addition, the side surfaces of the first lower protection layer 140a and the first upper protection layer 140b may be in contact with the drain electrode 175. The first lower protection layer 140a and the first upper protection layer 140b may include an insulating material or an insulator, or may be an insulating material or an insulator. In an embodiment, the first lower protection layer 140a and the first upper protection layer 140b include different materials. If the first lower protection layer 140a and the first upper protection layer 140b include the same material, it may be impossible to identify the boundary between the first lower protection layer 140a and the first upper protection layer 140b.

[0129] Next, refer to Figures 21 to 27 Describe a method of manufacturing a semiconductor device according to an embodiment.

[0130] Figures 21 to 27 is a process cross-sectional view shown according to the process sequence of manufacturing a semiconductor device according to an embodiment.

[0131] First, as Figure 21 shown, a seed layer 115, a buffer layer 120, a channel layer 132, a barrier layer 136, and a gate semiconductor material layer 152a may be sequentially formed on a substrate 110.

[0132] As Figure 22As shown, the gate semiconductor material layer 152a can be patterned to form the gate semiconductor layer 152. The gate semiconductor layer 152 can have a predetermined width. When the gate semiconductor material layer 152a is patterned, at least a portion of the barrier layer 136 located below the gate semiconductor material layer 152a can be exposed.

[0133] Next, an insulating material can be deposited on the barrier layer 136 and the gate semiconductor layer 152 to form the first lower protective layer 140a. The first lower protective layer 140a can cover the upper surface, the upper surface, and the side surfaces of the gate semiconductor layer 152 of the barrier layer 136.

[0134] As Figure 23 shown, the first lower protective layer 140a can be patterned to form an opening 145. The opening 145 of the first lower protective layer 140a can overlap with the gate semiconductor layer 152. At least a portion of the gate semiconductor layer 152 can be exposed to the outside through the opening 145. A portion of the upper surface of the gate semiconductor layer 152 can be exposed to the outside. For example, a portion of the upper surface of the gate semiconductor layer 152 can be exposed through the opening 145. In an embodiment, the width of the opening 145 is narrower than the width of the gate semiconductor layer 152. Therefore, the entire upper surface of the gate semiconductor layer 152 is not exposed to the outside, and only a portion of the upper surface of the gate semiconductor layer 152 can be exposed to the outside.

[0135] The width of the opening 145 is shown as being constant, but is not limited thereto. For example, the width of the opening 145 formed in the lower portion of the first lower protective layer 140a can be smaller than the width of the opening 145 formed in the upper portion of the first lower protective layer 140a. The width of the opening 145 can gradually increase as it moves away from the gate semiconductor layer 152.

[0136] As Figure 24 shown, the gate electrode material layer 155a can be formed by depositing a conductive material or a conductor on the first lower protective layer 140a. The gate electrode material layer 155a can fill the opening 145 of the first lower protective layer 140a. In an embodiment, at least a portion of the gate electrode material layer 155a that overlaps with the opening 145 is located at a lower level than a portion of the gate electrode material layer 155a located around the opening 145.

[0137] In this embodiment, the atomic percentages of the materials constituting the gate electrode material layer 155a may be constant. The gate electrode material layer 155a may be formed by supplying a gas at a constant flow rate. Accordingly, the gate electrode material layer 155a may have a constant atomic percentage in the thickness direction. For example, the gate electrode material layer 155a may include TiN, and the ratio of the atomic percentage of Ti to the atomic percentage of N in the upper part of the gate electrode material layer 155a may be substantially the same as the ratio of the atomic percentage of Ti to the atomic percentage of N in the lower part of the gate electrode material layer 155a. However, this is not limited thereto, and similar to the previous embodiments, the atomic percentages of the materials constituting the gate electrode material layer 155a may vary according to position.

[0138] As Figure 25 shown, the gate electrode 155 may be formed by patterning the gate electrode material layer 155a (e.g., see Figure 24 ).

[0139] The width of the gate electrode 155 may vary according to position. In an embodiment, the width of the portion of the gate electrode 155 located within the opening 145 of the first lower protective layer 140a is less than the width of the portion of the gate electrode 155 located above the first lower protective layer 140a. In an embodiment, the width of the lower part of the gate electrode 155 is less than the width of the upper part of the gate electrode 155. The width of the upper part of the gate electrode 155 may be the same as or similar to the width of the gate semiconductor layer 152. The width of the upper part of the gate electrode 155 may be the same as or substantially the same as the width of the gate semiconductor layer 152. However, this is not limited thereto, and the width of the upper part of the gate electrode 155 may be less than or greater than the width of the gate semiconductor layer 152. There may be a portion where the gate electrode 155 and the gate semiconductor layer 152 are separated. In the region where the gate electrode 155 and the gate semiconductor layer 152 are separated, the first lower protective layer 140a may be located between the gate electrode 155 and the gate semiconductor layer 152. The portion where the gate electrode 155 and the gate semiconductor layer 152 are separated may be a groove gv of the gate electrode 155, and the groove gv may be filled with the first lower protective layer 140a.

[0140] As Figure 26 shown, the first upper protective layer 140b may be formed by depositing an insulating material on the gate electrode 155 and the first lower protective layer 140a. The first upper protective layer 140b may cover a part of the side surface and the upper surface of the gate electrode 155 and the first lower protective layer 140a. The first lower protective layer 140a and the first upper protective layer 140b may constitute the first protective layer 140. In an embodiment, the first lower protective layer 140a and the first upper protective layer 140b include the same material. In an embodiment, the first lower protective layer 140a and the first upper protective layer 140b include different materials.

[0141] As Figure 27As shown, the first trench 141 and the second trench 143 can be formed by patterning the first protective layer 140. At this time, not only the first protective layer 140, but also the barrier layer 136 and the channel layer 132 can be patterned together.

[0142] A conductive material or a conductor can be deposited on the first protective layer 140 and patterned to form the source electrode 173 and the drain electrode 175. The source electrode 173 can be formed in the first trench 141 and electrically connected to one side of the channel layer 132. The drain electrode 175 can be formed in the second trench 143 and electrically connected to the other side of the channel layer 132.

[0143] Next, refer to Figure 28 to describe the semiconductor device according to an embodiment.

[0144] Figure 28 is a cross-sectional view showing a semiconductor device according to an embodiment.

[0145] Figure 28 Many parts of the embodiment shown are the same as those of the embodiment shown in Figure 20 so any redundant description thereof will be omitted, and the differences will be mainly described. In addition, the same reference numerals are used for components that are the same as those in the previous embodiment. Figure 28 The difference between the embodiment shown in

[0146] and the previous embodiment is that the gate electrode includes a first groove and a second groove. Figure 28 As shown, the first lower protective layer 140a can be located on the barrier layer 136 and the gate semiconductor layer 152, and the gate electrode 155 can be located between the first lower protective layer 140a and the first upper protective layer 140b. The gate electrode 155 can be connected to the gate semiconductor layer 152 through the opening 145 formed in the first lower protective layer 140a.

[0147] The gate electrode 155 includes a first groove gv1 and a second groove gv2. The first groove gv1 can be located below the second groove gv2. The first groove gv1 can be filled with the first lower protective layer 140a. The gate semiconductor layer 152 and the gate electrode 155 can be separated by the first groove gv1, and the first lower protective layer 140a can be located between the gate semiconductor layer 152 and the gate electrode 155. The second groove gv2 can be filled with the first upper protective layer 140b. The gate semiconductor layer 152 and the gate electrode 155 can be separated by the second groove gv2, and the first upper protective layer 140b can be located between the gate semiconductor layer 152 and the gate electrode 155. In the second groove gv2, the first upper protective layer 140b can be located between the first lower protective layer 140a and the gate electrode 155.

[0148] In an embodiment, the width of a portion of the gate electrode 155 adjacent to the first groove gv1 is different from the width of a portion of the gate electrode 155 adjacent to the second groove gv2. The width of the portion of the gate electrode 155 adjacent to the first groove gv1 may be smaller than the width of the portion of the gate electrode 155 adjacent to the second groove gv2. The width of the portion of the gate electrode 155 adjacent to the second groove gv2 may be smaller than the width of the portion of the gate electrode 155 where no groove is formed. The width of the lower portion of the gate electrode 155 may be smaller than the width of the upper portion of the gate electrode 155. The width of the middle portion of the gate electrode 155 may be greater than the width of the lower portion of the gate electrode 155 and may be smaller than the width of the upper portion. However, it is not limited thereto, and the relationship of the widths of each portion of the gate electrode 155 may be changed in various ways. For example, the width of the middle portion of the gate electrode 155 may be smaller than the width of the lower portion of the gate electrode 155 and may be smaller than the width of the upper portion.

[0149] In this embodiment, the atomic percentage of the material constituting the gate electrode 155 may vary according to the position. The second groove gv2 of the gate electrode 155 may be a step caused by different etching ratios in an etching process, and the etching ratio depends on the difference in the atomic percentage of the material constituting the gate electrode 155. The first groove gv1 of the gate electrode 155 may be a step caused by at least a portion of the inside of the opening 145 formed to fill the first lower protection layer 140a and other portions formed above the first lower protection layer 140a.

[0150] Next, refer to Figure 29 to describe a semiconductor device according to an embodiment.

[0151] Figure 29 is a cross-sectional view showing a semiconductor device according to an embodiment.

[0152] Figure 29 Many parts of the embodiment shown in Figure 28 are the same as those of the embodiment shown in Figure 29 and thus any redundant description thereof will be omitted, and the differences will be mainly described. In addition, the same reference numerals are used for components that are the same as those in the foregoing embodiments. In the embodiment shown in

[0153] As Figure 29As shown, the gate electrode 155 includes a first groove gv1 and a second groove gv2. In a previous embodiment, each of the first groove gv1 and the second groove gv2 had a square-shaped cross-section. In the present embodiment, the first groove gv1 has a square cross-section, and the second groove gv2 includes a cross-section with a curved surface. The second groove gv2 may have a concave curved surface shape. However, it is not limited thereto, and the shapes of the first groove gv1 and the second groove gv2 can be changed in various ways. As an example, both the first groove gv1 and the second groove gv2 may have a curved surface shape.

[0154] Next, refer to Figure 30 Describe a semiconductor device according to an embodiment.

[0155] Figure 30 is a cross-sectional view showing a semiconductor device according to an embodiment.

[0156] Figure 30 Many parts of the embodiment shown in Figure 20 are the same as the embodiment shown in Figure 30 and thus any redundant description thereof will be omitted, and the differences will be mainly described. In addition, the same reference numerals are used for components that are the same as those in the previous embodiment.

[0157] As Figure 30 shown, the first protective layer 140 may be located above the barrier layer 136 and the gate semiconductor layer 152. The source electrode 173 and the drain electrode 175 may penetrate the first protective layer 140 and the barrier layer 136 and be connected to the channel layer 132. The semiconductor device according to an embodiment further includes a second protective layer 160 located above the first protective layer 140, the source electrode 173, and the drain electrode 175. The upper surface of the first protective layer 140 may be covered by the second protective layer 160. A part of the side surfaces and the upper surface of the source electrode 173 and the drain electrode 175 may be covered by the second protective layer 160. The gate electrode 155 may be connected to the gate semiconductor layer 152 through the first protective layer 140 and the second protective layer 160.

[0158] The gate electrode 155 includes at least one groove gv. The groove gv of the gate electrode 155 may be filled with the first protective layer 140 and the second protective layer 160. In a region where the gate electrode 155 and the gate semiconductor layer 152 are separated, the first protective layer 140 and the second protective layer 160 may be located between the gate electrode 155 and the gate semiconductor layer 152.

[0159] Next, refer to Figures 31 to 34 Describe a method of manufacturing a semiconductor device according to an embodiment.

[0160] Figures 31 to 34It is a process cross-sectional view showing a semiconductor device according to an embodiment in the order of the manufacturing process.

[0161] First, as Figure 31 shown, a seed layer 115, a buffer layer 120, a channel layer 132, a blocking layer 136, and a gate semiconductor material layer may be sequentially formed on a substrate 110, and the gate semiconductor material layer may be patterned to form a gate semiconductor layer 152. Next, a first protective layer 140 may be formed by depositing an insulating material on the blocking layer 136 and the gate semiconductor layer 152.

[0162] As Figure 32 shown, the first protective layer 140 may be patterned to form a first trench 141 and a second trench 143. At this time, not only the first protective layer 140 but also the blocking layer 136 and the channel layer 132 may be patterned together.

[0163] A conductive material or a conductor may be deposited on the first protective layer 140 and patterned to form a source electrode 173 and a drain electrode 175. The source electrode 173 may be formed in the first trench 141 and electrically connected to one side of the channel layer 132. The drain electrode 175 may be formed in the second trench 143 and electrically connected to the other side of the channel layer 132.

[0164] As Figure 33 shown, a second protective layer 160 may be formed by depositing an insulating material on the first protective layer 140, the source electrode 173, and the drain electrode 175. The second protective layer 160 may cover the upper surface of the first protective layer 140, and may cover a part of the side surfaces and the upper surface of the source electrode 173 and the drain electrode 175.

[0165] As Figure 34 shown, a conductive material or a conductor may be deposited on the second protective layer 160 and patterned to form a gate electrode 155. After etching the first protective layer 140 and the second protective layer 160 to form an opening 145, the gate electrode 155 may be formed to fill the opening 145. In this embodiment, the atomic percentage of the material constituting the gate electrode 155 may be constant. However, this is not limited thereto, and as in the previous embodiment, the atomic percentage of the material constituting the gate electrode 155 may vary according to the position.

[0166] The width of the gate electrode 155 may vary according to the position. The width of the portion of the gate electrode 155 located within the openings 145 of the first protective layer 140 and the second protective layer 160 may be smaller than the width of the portion of the gate electrode 155 located above the second protective layer 160. The width of the lower portion of the gate electrode 155 may be smaller than the width of the upper portion of the gate electrode 155. The width of the upper portion of the gate electrode 155 may be the same as or similar to the width of the gate semiconductor layer 152. The width of the upper portion of the gate electrode 155 may be the same as or substantially the same as the width of the gate semiconductor layer 152. However, it is not limited thereto, and the width of the upper portion of the gate electrode 155 may be smaller than or larger than the width of the gate semiconductor layer 152. There may be a portion where the gate electrode 155 and the gate semiconductor layer 152 are separated. In the region where the gate electrode 155 and the gate semiconductor layer 152 are separated, the first protective layer 140 and the second protective layer 160 may be located between the gate electrode 155 and the gate semiconductor layer 152. The portion where the gate electrode 155 and the gate semiconductor layer 152 are separated may be the groove gv of the gate electrode 155, and the groove gv may be filled with the first protective layer 140 and the second protective layer 160.

[0167] Next, refer to Figure 35 to describe a semiconductor device according to an embodiment.

[0168] Figure 35 is a cross-sectional view showing a semiconductor device according to an embodiment.

[0169] Figure 35 Many parts of the embodiment shown in Figure 30 are the same as those of the embodiment shown in Figure 30 , so any redundant description thereof will be omitted, and the differences will be mainly described. In addition, the same reference numerals are used for components that are the same as those in the previous embodiments. Figure 35 The slight difference between the embodiment shown in Figure 35 and the previous embodiment is that the gate electrode includes a first groove and a second groove.

[0170] As Figure 35 shown, the first protective layer 140 may be located on the barrier layer 136 and the gate semiconductor layer 152. The source electrode 173 and the drain electrode 175 may penetrate the first protective layer 140 and the barrier layer 136 and be connected to the channel layer 132. The second protective layer 160 may be located on the first protective layer 140, the source electrode 173, and the drain electrode 175. The gate electrode 155 may be connected to the gate semiconductor layer 152 through the first protective layer 140 and the second protective layer 160.

[0171] The gate electrode 155 includes a first groove gv1 and a second groove gv2. The first groove gv1 is located below the second groove gv2. The first groove gv1 may be filled with a first protective layer 140. The second groove gv2 may be filled with a second protective layer 160. The width of the portion of the gate electrode 155 adjacent to the first groove gv1 may be smaller than the width of the portion of the gate electrode 155 adjacent to the second groove gv2. The width of the portion of the gate electrode 155 adjacent to the second groove gv2 may be smaller than the width of the portion of the gate electrode 155 where no groove is formed. The width of the lower portion of the gate electrode 155 may be smaller than the width of the upper portion of the gate electrode 155. The width of the middle portion of the gate electrode 155 may be larger than the width of the lower portion of the gate electrode 155 and may be smaller than the width of the upper portion.

[0172] Next, refer to Figure 36 to describe a semiconductor device according to an embodiment.

[0173] Figure 36 is a cross-sectional view showing a semiconductor device according to an embodiment.

[0174] Figure 36 Many parts of the embodiment shown in Figure 34 are the same as the embodiment shown in Figure 36 and thus any redundant description thereof will be omitted, and the differences will be mainly described. In addition, the same reference numerals are used for components that are the same as those in the previous embodiments. Figure 36 The slight difference between the embodiment shown in

[0175] and the previous embodiments is that the gate electrode includes a first groove and a second groove. Figure 36 As shown in

[0176] In this embodiment, the atomic percentage of the material constituting the gate electrode 155 may vary according to position. The second groove gv2 of the gate electrode 155 may be a step caused by different etching ratios in an etching process, which depends on the difference in the atomic percentage of the material constituting the gate electrode 155. The first groove gv1 of the gate electrode 155 may be a step caused by at least a part of the inside of the gate electrode 155 formed to fill the opening of the first protective layer 140 and the second protective layer 160 and other parts formed on the second protective layer 160.

[0177] Although the present disclosure has been described in connection with presently considered practical exemplary embodiments, it will be understood that the inventive concept is not limited to the disclosed embodiments, but on the contrary, the inventive concept is intended to cover various modifications and equivalent arrangements included within the spirit and scope of the appended claims.

Claims

1. A semiconductor device, comprising: A channel layer; A blocking layer, which is located above the channel layer and includes a material having an energy bandgap different from that of the channel layer; A source electrode and a drain electrode located on the channel layer; A gate electrode, which is located above the blocking layer between the source electrode and the drain electrode; And A gate semiconductor layer, which is located between the blocking layer and the gate electrode, Wherein, at the joint surface of the gate electrode and the gate semiconductor layer, the width of the gate electrode is smaller than the width of the gate semiconductor layer.

2. The semiconductor device according to claim 1, wherein, The width of the lower part of the gate electrode is smaller than the width of the upper part of the gate electrode.

3. The semiconductor device according to claim 2, wherein, The width of the gate electrode gradually increases from the lower part to the upper part.

4. The semiconductor device according to claim 2, wherein, The width of the gate electrode gradually increases from the lower part to the upper part and then becomes constant.

5. The semiconductor device according to claim 1, wherein: The gate electrode includes titanium nitride TiN, and The ratio of the atomic percentage of Ti to the atomic percentage of N in the upper part of the gate electrode is lower than the ratio of the atomic percentage of Ti to the atomic percentage of N in the lower part of the gate electrode.

6. The semiconductor device according to claim 5, wherein, The atomic percentage of Ti in the gate electrode based on the total number of atoms in the gate electrode decreases or remains constant as it is farther away from the gate semiconductor layer.

7. The semiconductor device according to claim 6, wherein: The atomic percentage of Ti in the lower part of the gate electrode based on the total number of atoms in the gate electrode is 40 atomic percentage at% or more and 60 at% or less, and The atomic percentage of Ti in the upper part of the gate electrode based on the total number of atoms in the gate electrode is 20 at% or more and 50 at% or less.

8. The semiconductor device according to claim 5, wherein, The atomic percentage of N in the gate electrode based on the total number of atoms in the gate electrode increases or remains constant as it is farther away from the gate semiconductor layer.

9. The semiconductor device according to claim 8, wherein: The atomic percentage of N in the lower part of the gate electrode based on the total number of atoms in the gate electrode is 40 at% or more and 60 at% or less, and The atomic percentage of N in the upper part of the gate electrode based on the total number of atoms in the gate electrode is 50 at% or more and 80 at% or less.

10. The semiconductor device according to claim 1, wherein: The gate electrode includes a groove recessed from the bottom surface and the side surface, and At least a part of the gate electrode is separated from the gate semiconductor layer through the groove.

11. The semiconductor device according to claim 10, wherein, The depth of the groove of the gate electrode is 5 nanometers nm or more and 300 nm or less.

12. The semiconductor device according to claim 10, wherein, The thickness of the gate electrode is or greater and or less.

13. The semiconductor device according to claim 10, further comprising a first protective layer located above the blocking layer and the gate electrode, Among them, The first protective layer is located between the gate semiconductor layer and the gate electrode in the groove.

14. The semiconductor device according to claim 10, wherein, The groove has at least one of the shapes of a triangle, a square, and a stepped shape, or includes a curved surface in a cross section.

15. A semiconductor device, comprising: A channel layer, which includes gallium nitride GaN; A blocking layer, which is located above the channel layer and includes aluminum gallium nitride AlGaN; A source electrode and a drain electrode located on the channel layer; And A gate electrode, which is located above the barrier layer between the source electrode and the drain electrode and includes titanium nitride TiN, wherein, the ratio of the atomic percentage of Ti to the atomic percentage of N in the upper part of the gate electrode is lower than the ratio of the atomic percentage of Ti to the atomic percentage of N in the lower part of the gate electrode.

16. The semiconductor device according to claim 15, wherein: the atomic percentage of Ti based on the total number of atoms in the gate electrode decreases or remains constant as it is farther away from the barrier layer, the atomic percentage of Ti based on the total number of atoms in the gate electrode in the lower part of the gate electrode is 40 atomic percentage at% or more and 60 at% or less, and the atomic percentage of Ti based on the total number of atoms in the gate electrode in the upper part of the gate electrode is 20 at% or more and 50 at% or less.

17. The semiconductor device according to claim 15, wherein: the atomic percentage of N based on the total number of atoms in the gate electrode increases or remains constant as it is farther away from the barrier layer, the atomic percentage of N based on the total number of atoms in the gate electrode in the lower part of the gate electrode is 40 atomic percentage at% or more and less than 60 at%, and the atomic percentage of N based on the total number of atoms in the gate electrode in the upper part of the gate electrode is 50 at% or more and 80 at% or less.

18. The semiconductor device according to claim 15, further comprising: a gate semiconductor layer, which is located between the barrier layer and the gate electrode, wherein: the width of the lower part of the gate electrode is smaller than the width of the upper part of the gate electrode, and the width of the lower part of the gate electrode is smaller than the width of the gate semiconductor layer.

19. A semiconductor device, comprising: a channel layer; a barrier layer, which is located above the channel layer and includes a material having an energy band gap different from that of the channel layer; a source electrode and a drain electrode located on the channel layer; a gate electrode, which is located above the barrier layer between the source electrode and the drain electrode; and a gate semiconductor layer, which is located between the barrier layer and the gate electrode, wherein, the width of the lower part of the gate electrode is smaller than the width of the upper part of the gate electrode.

20. The semiconductor device according to claim 19, wherein: the gate electrode includes titanium nitride TiN, and the ratio of the atomic percentage of Ti to the atomic percentage of N in the upper part of the gate electrode is lower than the ratio of the atomic percentage of Ti to the atomic percentage of N in the lower part of the gate electrode.

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