KR20140139890A - Nitride semiconductor and method thereof - Google Patents

Abstract

The present specification provides a semiconductor device and a manufacturing method thereof, capable of obtaining an improved threshold voltage property and an improved leakage current property through a structure on which an AlN layer (or AlN nucleation layer), an AlGaN buffer layer, and a superlattice layer are successively stacked. For this, the semiconductor device according to one embodiment of the present invention includes the AlN layer, the AlGaN buffer layer which is formed on the AlN layer, the superlattice layer which is formed on the AlGaN buffer layer, a GaN layer which is formed on the superlattice layer, and an AlGaN barrier layer which is formed on the GaN layer.

Description

[0001] NITRIDE SEMICONDUCTOR DEVICE AND METHOD FOR MANUFACTURING [0002]

The present invention relates to a semiconductor device having improved threshold voltage characteristics and leakage current characteristics through sequentially stacked AlN layers (or AlN nucleation layers), AlGaN buffer layers, and superlattice layer structures, and a manufacturing method thereof.

With the emphasis on green energy, the importance of power semiconductors is growing. Power semiconductors used in inverters such as electric vehicles, air conditioners and refrigerators are currently being manufactured by Silicon. However, nitride semiconductors of new materials are attracting attention as high critical electric field, low on resistance, high temperature and high frequency operation characteristics as compared with silicon and are being studied as materials of next generation power semiconductor devices.

Recently, mainstream power MOSFETs and IGBTs have been widely used in high output power devices, and devices such as HEMTs, HFETs, and MOSFETs have been studied in GaN series.

In the case of HEMTs, high-electron mobility is used for communication devices having high-frequency characteristics.

In addition, HEMTs have been used for power semiconductor devices and communication devices with high frequency characteristics. In recent years, hybrid / fuel cell vehicles are being developed, and hybrid cars are being launched by many overseas companies. A voltage booster converter that connects a motor and a generator in a hybrid vehicle and a semiconductor switch in the inverter require reliable operation at high temperatures due to the heat generated by the engine. The wide bandgap of GaN enables reliable high temperature operation and is suitable as a next-generation semiconductor switch in hybrid vehicles.

Among them, Furukawa Electric of Japan has announced the discrete high-electron-mobility transistor (HEMT) of AlGaN / GaN. It has high breakdown voltage of 750 V and low on-resistance of 6.3 mΩ-cm2, , Si superjunction MOSFET and SiC MESFET. In addition, GaN discrete was stable at a high temperature of 225 ℃.

BRIEF DESCRIPTION OF THE DRAWINGS Figure 1 is an exemplary diagram illustrating the general structure of a heterojunction field effect transistor (HFET).

Referring to FIG. 1, a general HFET can switch a 2DEG current flowing from a drain electrode to a source electrode through a schottky gate electrode.

A general HFET 10 includes a substrate (not shown), a first GaN layer 11 formed on the substrate, an AlGaN layer 12 formed on the first GaN layer, a second GaN layer 12 formed on the AlGaN layer, A layer 13, a gate electrode 14, a source electrode 15 and a drain electrode 16 formed on the second GaN layer.

On the other hand, in the case of a device using GaN, the price and characteristics of the device may be changed depending on the substrate selection. GaN on Silicon is the most commonly used structure due to its low cost and the establishment of a silicon process. However, due to the high lattice mismatch, epi can be defective and the silicon substrate is stressed, resulting in high bow and surface cracks. If GaN is directly grown on the silicon, the silicon may be etched on the GaN due to the melting back phenomenon.

It is an object of the present invention to provide a semiconductor device having improved threshold voltage characteristics and leakage current characteristics through a sequentially stacked AlN layer (or AlN nucleation layer), an AlGaN buffer layer and a superlattice layer structure, and a manufacturing method thereof have.

According to an aspect of the present invention, there is provided a semiconductor device comprising: an AlN layer; An AlGaN buffer layer formed on the AlN layer; A superlattice layer formed on the AlGaN buffer layer; A GaN layer formed on the superlattice layer; And an AlGaN barrier layer formed on the GaN layer.

As one example related to the present specification, the AlN layer may include a plurality of layers made of AlN grown at different temperatures.

As an example related to the present specification, the number of the plurality of layers made of AlN grown at the different temperatures may be 2 to 5.

As one example related to the present specification, the AlN layer includes: a first AlN layer grown at a low temperature; And a second AlN layer formed on the first AlN layer and grown at a high temperature.

As one example related to the present specification, the AlGaN buffer layer may include a plurality of layers made of AlGaN having different Al compositions.

As an example related to the present specification, the number of the plurality of layers made of AlGaN having different Al compositions may be 2 to 5.

As an example related to the present specification, the Al composition of at least one of the AlN layer and the AlGaN buffer layer may be 1% to 70%.

As one example related to the present specification, the Al composition of at least one of the AlN layer and the AlGaN buffer layer may be gradually decreased in the stacking direction.

As an example related to the present specification, the thickness of at least one of the AlN layer and the AlGaN buffer layer may be 0.1 um to 3.0 um.

As an example related to the present specification, the thickness of the superlattice layer may be 0.3 um to 4.0 um.

As an example related to the present specification, the superlattice layer may be formed by laminating a plurality of superlattice thin film layers in which two different first thin film layers and second thin film layers are stacked.

As an example related to the present specification, the first thin film layer may be made of AlN or AlGaN, and the second thin film layer may be made of GaN.

As an example related to the present specification, the composition of Al contained in the first thin film layer may be 50% to 99%.

As an example related to the present specification, the thickness of the first thin film layer may be 1 nm to 20 nm.

As an example related to the present specification, the thickness of the second thin film layer may be 10 nm to 70 nm.

As an example related to the present specification, the number of the superlattice thin film layers to be stacked may be 60 to 120.

As one example related to the present specification, the superlattice layer may be doped with a p-type dopant.

As one example related to the present specification, the p-type dopant may be at least one of Mg, C and Fe.

As an example related to the present specification, the concentration of the p-type dopant may be 1e ¹⁶ / cm ³ to 5e ²⁰ / cm ³ .

As an example related to the present specification, the concentration of the p-type dopant may be gradually decreased in the stacking direction of the superlattice layer.

As an example related to the present specification, the thickness of the GaN layer may be 0.5 um to 4.0 um.

As an example related to the present specification, the GaN layer may be doped with at least one dopant of Mg, C and Fe.

As an example related to the present specification, the at least one dopant concentration may be 1e ¹⁶ / cm ³ to 5e ²⁰ / cm ³ .

As one example related to the present specification, the GaN layer may include a plurality of layers made of GaN grown at different temperatures.

As an example related to the present specification, the number of the plurality of layers made of GaN grown at different temperatures may be 2 to 5.

As an example related to the present specification, the composition of Al in the AlGaN barrier layer may be 10% to 30%.

As one example related to the present specification, the thickness of the AlGaN barrier layer may be 5 nm to 50 nm.

As one example related to the present specification, the AlN layer may be formed on a substrate.

As one example related to the present specification, the substrate may be made of at least one of Si, SiC, Sapphire, and GaN.

As an example related to the present specification, the semiconductor device may further include a source electrode, a drain electrode, and a gate electrode formed on a part of the AlGaN barrier layer.

According to another aspect of the present invention, there is provided a method of manufacturing a semiconductor device, including: forming an AlN layer on a substrate; Forming an AlGaN buffer layer on the AlN layer; Forming a superlattice layer on the AlGaN buffer layer; Forming a GaN layer on the superlattice layer; And forming an AlGaN barrier layer on the GaN layer.

At least one of the AlN layer, the AlGaN buffer layer, the superlattice layer, the GaN layer, and the AlGaN barrier layer may be formed by metal organic chemical vapor deposition (MOCVD), molecular beam epitaxy (MBE) , HILP vapor deposition (HVPE), plasma enhanced chemical vapor deposition (PECVD), sputtering, and atomic layer deposition (ALD).

According to an embodiment disclosed herein, a semiconductor device having improved threshold voltage characteristics and leakage current characteristics through sequentially stacked AlN layers (or AlN nucleation layers), AlGaN buffer layers, and superlattice layer structures, and a method of manufacturing the same .

In particular, according to the semiconductor device disclosed in this specification, it is possible to provide a semiconductor device having a sequentially stacked AlN layer (or AlN nucleation layer), an AlGaN buffer layer, and a super lattice layer structure, and a manufacturing method thereof, leakage current is decreased and insertion of AlN layer with lower thermal expansion coefficient than AlGaN may be advantageous in reducing the probability of occurrence of crack at cooling down.

BRIEF DESCRIPTION OF THE DRAWINGS Figure 1 is an exemplary diagram illustrating the general structure of a heterojunction field effect transistor (HFET).
2 is an exemplary view showing a structure of a semiconductor device according to an embodiment disclosed herein.
3 is a graph illustrating the doping profile of an Fe dopant according to one embodiment disclosed herein.
4 is a graph depicting the doping profile of an Fe dopant according to another embodiment disclosed herein.
5 is a flowchart showing a method of manufacturing a semiconductor device according to an embodiment disclosed herein.
6A to 6E are views showing an example of a method of manufacturing a semiconductor device according to an embodiment disclosed in this specification.

The techniques disclosed herein can be applied to a heterojunction field effect transistor and a manufacturing method thereof. However, the technique disclosed in this specification is not limited thereto, and can be applied to all nitride-based semiconductor devices to which the technical idea of the above-described technique can be applied and a manufacturing method thereof.

In recent years, according to the growth technology of a nitride semiconductor, the development of a light emitting diode and a blue-violet laser diode covering a red wavelength band in ultraviolet rays has been completed and has already been widely used in traffic lights, electric sign boards, mobile phones and the like.

In addition, GaN, which is a typical nitride semiconductor, has a large band gap energy and can form a two-dimensional 2DEG channel through heterojunction, so that the threshold voltage is high and high-speed operation can be performed.

These high power, high speed characteristics are attracting attention as a next generation power semiconductor material because they are well suited for power semiconductors that require high operating voltage and low energy loss on switching.

However, since compound semiconductors are generally used on different substrates, stress and defects due to difference in lattice constant may occur, and it is difficult to grow a high-quality epi layer due to crystal defects caused by incomplete bonding of compounds, There may be disadvantages that exist.

The disclosed technology relates to a method of fabricating a nitride semiconductor HFET device, and more particularly, to a device manufacturing method and structure for making a high power device.

Specifically, the techniques disclosed herein can be used to grow an AlN nucleation layer (or an AlN nucleation layer) by growing single or two to three different temperature layers on a Silicon substrate and growing an AlGaN buffer layer (or buffer layer) therefor GaN and AlN, or GaN and AlGaN alternately grow to form a super-lattice layer, thereby reducing the leakage current generated in the buffer layer and growing a buffer layer thicker than the AlGaN buffer, thereby facilitating bowing and cracking And the like.

In addition, by growing the buffer layer thicker, it becomes possible to grow more AlN having a large bandgap, which can improve the device breakdown voltage characteristic as a high power device.

Further, according to the technique disclosed in this specification, the AlN layer is grown on the silicon as a nucleation layer (nucleation layer) to prevent direct contact between GaN and silicon (Silicon) The growth of GaN and AlN with other Al compositions may have the effect of reducing the lattice mismatch between GaN and AlN.

The present invention also relates to a nitride semiconductor power device and a method of fabricating the same, which can reduce the lattice mismatch between GaN and Silicon, reduce the AlGaN buffer used to stably grow GaN on a silicon wafer buffer layer by growing AlN and GaN, or AlGaN and GaN in the order of 60-120 paris, in order to increase the thickness of the Al-containing layer. it is possible to reduce the leakage current and to reduce the probability of cracking during cooling down by inserting AlN having a lower thermal expansion coefficient than AlGaN.

It is noted that the technical terms used herein are used only to describe specific embodiments and are not intended to limit the scope of the technology disclosed herein. Also, the technical terms used herein should be interpreted as being generally understood by those skilled in the art to which the presently disclosed subject matter belongs, unless the context clearly dictates otherwise in this specification, Should not be construed in a broader sense, or interpreted in an oversimplified sense. In addition, when a technical term used in this specification is an erroneous technical term that does not accurately express the concept of the technology disclosed in this specification, it should be understood that technical terms which can be understood by a person skilled in the art are replaced. Also, the general terms used in the present specification should be interpreted in accordance with the predefined or prior context, and should not be construed as being excessively reduced in meaning.

Also, the singular forms "as used herein include plural referents unless the context clearly dictates otherwise. In this specification, the terms "comprising ", or" comprising ", etc. should not be construed as necessarily including the various elements or steps described in the specification, Or may be further comprised of additional components or steps.

Furthermore, terms including ordinals such as first, second, etc. used in this specification can be used to describe various elements, but the elements should not be limited by the terms. The terms are used only for the purpose of distinguishing one component from another. For example, without departing from the scope of the present invention, the first component may be referred to as a second component, and similarly, the second component may also be referred to as a first component.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings, wherein like reference numerals denote like or similar elements, and redundant description thereof will be omitted.

Further, in the description of the technology disclosed in this specification, a detailed description of related arts will be omitted if it is determined that the gist of the technology disclosed in this specification may be obscured. It is to be noted that the attached drawings are only for the purpose of easily understanding the concept of the technology disclosed in the present specification, and should not be construed as limiting the spirit of the technology by the attached drawings.

In the nitride-based semiconductor device, In the buffer layer  Explanation for

In power semiconductors, nitride semiconductors (GaN) are attracting attention as devices with high breakdown voltage and low on-resistance.

However, it is difficult to grow the device because the cost of the substrate is high and it is difficult to grow the device to maintain the lattice mismatch without defective GaN.

In addition, sapphire and SiC can not be processed by conventional semiconductor processes in post-growth process, so new process processes may need to be developed.

For this reason, we will use Silicon, which is a low-cost, low-cost substrate for semiconductor processing. In the case of Silicon, lattice mismatch with GaN, which is a nitride semiconductor, If the device is fabricated, the leakage current of the device can be increased by acting as a leakage path.

Therefore, when a buffer layer such as AlGaN is inserted between the GaN and the silicon substrate, the defect density can be reduced by reducing the lattice mismatch, and the Epi stress due to the difference in the lattice constant between the GaN and the silicon is reduced , even if the thicker GaN is grown, the generation of cracks can be prevented.

In the case of the device using Grade AlGaN buffer, the AlGaN layer having 1 to 5 Al compositions is grown on the AlN nucleation layer, thereby reducing the latitude mismatch between the silicon and the GaN buffer layer and growing the thick GaN buffer layer There may be advantages to grow.

Hereinafter, the buffer layer in the nitride semiconductor device according to the embodiment disclosed in this specification will be described in more detail.

II-V compound semiconductors are advantageous for high-speed and high-power devices because they can produce devices with high mobility and high current density by using 2-dimentional electron gas (2DEG) due to heterojunction have.

However, due to the 2DEG generated by the structural characteristics, the device has a normally-on characteristic, and since the additional voltage is applied for the off state, the standby state of the device also consumes power.

Compound semiconductors such as GaN have a weak n-type doping effect without intentional doping due to N-vacancy occurring in the bonding process such as Gallium and Nitride, and donors derived from impurities existing in the reaction chamber .

This defects and impurities act to lower the resistivity of GaN, which may cause leakage current problems to the outside region of the active layer.

The MOCVD process is known to typically form GaN with an electron concentration of 1 x 10 ¹⁶ cm ^-3 .

In addition, since they are grown on different substrates such as sapphire, SiC, and Si, defects due to the difference in lattice constant with the substrate are generated. Therefore, when a conductive substrate such as Si is used, it is vulnerable to leakage current. Therefore, there is a need for a method for suppressing the leakage current and the leakage current through the buffer layer (or the buffer layer) and the normally off-off characteristic of the device.

There are several ways to reduce the leakage current from the epilayers in a nitride semiconductor power device with a heterojunction structure.

In particular, there may be a method of growing at least one buffer layer between the substrate and the GaN layer to reduce the leakage current.

In addition, in order to efficiently reduce the leakage current through the buffer layer, not only the semi-insulating function of the GaN channel needs to be strengthened, but also the crystal defects of the buffer layer for growing the buffer layer are minimized and the semi-insulating property is also increased, It may be necessary to minimize the vertical and lateral leakage currents.

This is a particularly necessary part of the operation of a high power device.

The technique disclosed herein is intended to propose an effective epitaxial structure that reduces the leakage current of the buffer layer for GaN growth.

According to one embodiment disclosed herein, there are three kinds of buffer layers for growing GaN on a substrate (for example, a Si substrate). For example, the buffer layer may have a structure including at least one of AlN, AlGaN, and superlattice.

According to one embodiment, the AlN layer (or AlN nucleation layer) may comprise a plurality of layers of AlN grown at different temperatures.

For example, the number of the plurality of layers made of AlN grown at the different temperatures may be 2 to 5.

Also, for example, an AlN buffer can be used in combination of low temperature and high temperature. That is, the lower portion of the AlN buffer may be formed by low temperature growth, and the upper portion of the AlN buffer may be formed by high temperature growth. In this case, the AlN layer may include a first AlN layer grown at a low temperature and a second AlN layer grown on the first AlN layer and grown at a high temperature.

In addition, according to one embodiment, the AlGaN buffer may include a plurality of layers made of AlGaN having different Al compositions.

For example, the number of the plurality of layers made of AlGaN having different Al compositions may be 2 to 5.

Also, for example, a continuous graded or graded buffer having a high Al content in the lower layer of the AlGaN buffer and a low Al composition in the upper layer may be used.

Also, according to one embodiment, the buffer layer may have a superlattice buffer structure.

The superlattice buffer structure may be a structure in which two different thin film layers (or ultra thin film layers) are stacked.

For example, a combination of AlN / GaN or AlGaN / GaN may be used for the superlattice buffer structure.

Therefore, in the case where the buffer layer has a superlattice buffer structure (or a superlattice layer), the buffer layer (or superlattice layer) having the superlattice structure may be formed by alternately stacking two different thin film layers have.

Among the three buffers, the superlattice structure has the lowest characteristics in terms of leakage current.

According to the embodiment disclosed herein, the three types of buffer layers may be used as a single buffer layer, but they may be combined with each other and provided in one semiconductor element.

For example, the AlN buffer (or AlN buffer layer) may be formed on a substrate, and the superlattice buffer (in other words, a superlattice buffer layer or superlattice layer) may be formed on the AlN buffer layer. In this case, the AlN buffer layer is a seed layer for growing GaN on the substrate, and may be referred to as a nucleation layer.

Accordingly, the heterojunction nitride based semiconductor device according to an embodiment disclosed herein may include at least one buffer layer (which may include a nucleation layer) formed on a substrate, a GaN layer formed on the at least one buffer layer Or a channel layer), an AlGaN barrier layer formed on the GaN layer and serving as an active layer, and a source electrode, a drain electrode, and a gate electrode formed on a part of the AlGaN barrier layer.

In general, the type of the substrate may be Si, SiC, an insulating substrate (e.g., sapphire substrate), a GaN substrate, or the like.

For example, when the substrate is a Si substrate, when the GaN layer is grown (or deposited or laminated) directly on the Si substrate, the crystallinity of the GaN layer is lowered due to the difference in lattice constant between Si and GaN, There may be a problem that the leakage current increases and the breakdown voltage characteristic deteriorates.

Therefore, as described above, by growing at least one buffer layer in the middle instead of growing the GaN layer directly on the Si substrate, it is possible to improve the crystallinity of the GaN layer and improve the leakage current characteristic and the breakdown voltage characteristic have.

Hereinafter, the structure of the semiconductor device according to the embodiment disclosed herein will be described with reference to FIGS. 2 to 4. FIG.

The work disclosed herein In the embodiment  Description of the semiconductor device according to

A semiconductor device according to one embodiment disclosed herein includes an AlN layer, an AlGaN buffer layer formed on the AlN layer, a superlattice layer formed on the AlGaN buffer layer, a GaN layer formed on the superlattice layer, Lt; RTI ID = 0.0 > AlGaN < / RTI >

According to one embodiment, the AlN layer may include a plurality of layers made of AlN grown at different temperatures.

In addition, according to an embodiment, the number of the plurality of layers made of AlN grown at different temperatures may be 2 to 5.

Further, according to one embodiment, the AlN layer includes a first AlN layer grown at a low temperature,

And a second AlN layer formed on the first AlN layer and grown at a high temperature.

Also, according to one embodiment, the AlGaN buffer layer may include a plurality of layers made of AlGaN having different Al compositions.

In addition, according to an embodiment, the number of the plurality of layers made of AlGaN having different Al compositions may be 2 to 5.

According to an embodiment, the Al composition of at least one of the AlN layer and the AlGaN buffer layer may be 1% to 70%.

According to one embodiment, the Al composition of at least one of the AlN layer and the AlGaN buffer layer may be gradually decreased in the stacking direction.

Also, according to one embodiment, the thickness of at least one of the AlN layer and the AlGaN buffer layer may be 0.1 um to 3.0 um.

Also, according to one embodiment, the thickness of the superlattice layer may be 0.3 um to 4.0 um.

According to an embodiment, the superlattice layer may be formed by laminating a plurality of superlattice thin film layers in which two different first thin film layers and second thin film layers are stacked.

According to an embodiment, the first thin film layer may be made of AlN or AlGaN, and the second thin film layer may be made of GaN.

In addition, according to one embodiment, the composition of Al contained in the first thin film layer may be 50% to 99%.

Also, according to one embodiment, the thickness of the first thin film layer may be 1 nm to 20 nm.

Also, according to one embodiment, the thickness of the second thin film layer may be 10 nm to 70 nm.

Also, according to one embodiment, the number of the superlattice thin film layers to be stacked may be 60 to 120.

Also, according to one embodiment, the superlattice layer may be doped with a p-type dopant.

Also, according to one embodiment, the p-type dopant may be at least one of Mg, C, and Fe.

Also, according to one embodiment, the concentration of the p-type dopant may be 1e ¹⁶ / cm ³ to 5e ²⁰ / cm ³ .

Also, according to one embodiment, the concentration of the p-type dopant may be gradually decreased in the stacking direction of the superlattice layer.

Also, according to one embodiment, the thickness of the GaN layer may be 0.5 um to 4.0 um.

Also, according to one embodiment, the GaN layer may be doped with at least one dopant of Mg, C, and Fe.

Also, according to one embodiment, the at least one dopant concentration may be 1e ¹⁶ / cm ³ to 5e ²⁰ / cm ³ .

Also, according to one embodiment, the GaN layer may include a plurality of layers of GaN grown at different temperatures.

Also, according to one embodiment, the number of the plurality of layers made of GaN grown at different temperatures may be 2 to 5.

Also, according to one embodiment, the composition of Al in the AlGaN barrier layer may be 10% to 30%.

Also, according to one embodiment, the thickness of the AlGaN barrier layer may be 5 nm to 50 nm.

Also, according to one embodiment, the AlN layer may be formed on a substrate.

According to an embodiment, the substrate may be made of at least one of Si, SiC, Sapphire, and GaN.

According to an exemplary embodiment, a source electrode, a drain electrode, and a gate electrode may be formed on a portion of the AlGaN barrier layer.

2 is an exemplary view showing a structure of a semiconductor device according to an embodiment disclosed herein.

Referring to FIG. 2, a semiconductor device 100 according to an embodiment disclosed herein includes an AlN layer 110, an AlGaN buffer layer 120, a superlattice layer 130, a GaN layer 140, and an AlGaN barrier layer 150).

The semiconductor device 100 may further include a GaN layer cap layer (not shown) formed on the AlGaN barrier layer 150.

In addition, the semiconductor device 100 may further include an oxide layer 190 for preventing surface leakage current.

The semiconductor device 100 may further include a source electrode 170, a drain electrode 180, and a gate electrode 160 formed on a part of the AlGaN barrier layer 150.

The semiconductor device 100 according to the embodiment disclosed herein may switch the 2DEG (CDEG) current flowing from the drain electrode to the source electrode through the schottky gate electrode.

Here, the AlN layer 110 may be formed on a substrate (not shown).

According to one embodiment, the substrate may be n-type, p-type, or various types of materials. For example, the substrate may be at least one of an insulating substrate, a sapphire substrate, a GaN substrate, a SiC substrate, and a Si substrate. It will be apparent to those skilled in the art that various types of substrates may be applied to the semiconductor devices disclosed herein.

Further, the substrate can be removed after fabrication of the semiconductor device 100. [ Thus, the final structure of the semiconductor device may be a structure without the substrate.

According to one embodiment, the AlN layer 110 may include a plurality of layers made of AlN grown at different temperatures.

In this case, the number of the plurality of layers made of AlN grown at different temperatures may be 2 to 5.

That is, the AlN layer 110 can be grown under various conditions. For example, the AlN layer 110 may include a first AlN layer grown at a low temperature and a second AlN layer grown on the first AlN layer and grown at a high temperature.

The AlGaN buffer layer 120 may include a plurality of layers made of AlGaN having different Al compositions.

Here, the number of the plurality of layers made of AlGaN having different compositions of Al may be 2 to 5.

In addition, according to one embodiment, the composition ratio of Al to the AlGaN buffer layer 120 may be changed according to the stacking direction. For example, the AlGaN buffer layer 120 may be composed of AlGaN whose composition of Al is gradually decreased in the stacking direction.

That is, the Al composition of the AlGaN layer can be represented by Al _x Ga _{1 - x} N (0 _{? X} ? 1). For example, the composition of Al may be continuous and gradually decrease. Further, for example, the composition of Al may be gradually decreased in a stepwise (or stepwise) manner.

The change in the Al composition may be similar to the Fe doping concentration profile of the superlattice layer 130 described in FIGS. 3 to 4, which will be described later.

It is apparent to those skilled in the art that the AlGaN buffer layer 120 may be formed based on various materials, composition ratios, and growth conditions.

The AlGaN buffer layer 120 may be formed by various methods (or methods). For example, the AlGaN buffer layer 120 may be formed by selectively growing a nitride semiconductor crystal. The AlGaN buffer layer 120 may be formed by a metal organic vapor phase epitaxy (MOCVD) method, a molecular beam epitaxial growth method (MBE) HVPE). ≪ / RTI > However, considering the crystallinity of the AlGaN buffer layer 120, MOCVD may be used for device fabrication.

According to one embodiment, the Al composition of at least one of the AlN layer 110 and the AlGaN buffer layer 120 may be 1% to 70%.

Also, according to one embodiment, the Al composition of at least one of the AlN layer 110 and the AlGaN buffer layer 120 may be gradually decreased in the stacking direction.

Also, according to one embodiment, the thickness of at least one of the AlN layer 110 and the AlGaN buffer layer 120 may be 0.1 um to 3.0 um.

The thickness of the superlattice layer 130 may be 0.3 um to 4.0 um.

The superlattice layer 130 may be formed by stacking a plurality of superlattice thin film layers 133 in which two first thin film layers 131 and a second thin film layer 132 are stacked.

In other words, the superlattice layer 130 may be formed by alternately stacking a first thin film layer 131 and a second thin film layer 132, which are two different thin film layers.

The superlattice thin film layer 133 may be formed of various materials. For example, the superlattice thin film layer 110c may include at least one of AlN / GaN and AlGaN / GaN superlattice structures.

That is, according to one embodiment, the first thin film layer 131 may be made of AlN or AlGaN, and the second thin film layer 132 may be made of GaN.

Further, this may mean that the two different thin film layers 131 and 132 are each formed of a combination of AlN / GaN or AlGaN / GaN. It is apparent to those skilled in the art that the superlattice thin film layer 133 may be formed of various materials.

According to one embodiment, the Al composition in the AlN and AlGaN may vary along the stacking direction. For example, the Al composition may be similar to the Al compositional change of the AlGaN buffer layer described above (see FIGS. 3 to 4).

According to one embodiment, the composition of Al contained in the first thin film layer 131 may be 50% to 99%.

Also, according to one embodiment, the thickness of the first thin film layer 131 may be 1 nm to 20 nm.

In addition, according to one embodiment, the thickness of the second thin film layer 132 may be 10 nm to 70 nm.

Also, according to one embodiment, the number of superlattice thin film layers 133 stacked in the superlattice layer 130 may be 60-120.

That is, the superlattice layer 130 may include 60 to 120 superlattice thin film layers 133. In other words, the superlattice layer 130 may include two different thin film layers 131 and 132 of 60 to 120 pairs. In other words, the superlattice layer 130 may be formed by stacking the two different thin film layers 131 and 132 alternately from 119 to 239 times.

The superlattice layer 130 may be formed in a variety of ways (or methods). For example, the superlattice layer 130 may be formed by selectively growing a nitride semiconductor crystal. The superlattice layer 130 may be formed by a metal organic vapor phase epitaxy (MOCVD), a molecular beam epitaxy (MBE) (HVPE). ≪ / RTI > However, considering the crystallinity of the superlattice layer 130, MOCVD may be used for device fabrication.

According to one embodiment disclosed herein, the superlattice buffer structure (or superlattice layer 130) may be formed by doping a specific dopant.

According to one embodiment, the specific dopant may be a p-type dopant. For example, the p-type dopant may be at least one of Mg, C, and Fe.

The p-type dopant may be doped into the superlattice layer 130 in a variety of ways (or methods).

For example, when the p-type dopant is C, a growth rate of GaN is increased in order to perform carbon doping in the super lattice layer 130 so that the carbon content in the TMGa source itself is formed high in the GaN crystal (or Doping the p-type dopant into the superlattice layer 130. In this case,

Also, for example, if the p-type dopant is Fe, a new trap is generated by intentionally Fe doping (or on the basis of) the Cp2Fe source, thereby reducing the quality of the thin film and bringing about a semi-insulating effect A superlattice buffer structure can be formed.

When the p-type dopant is Fe, the crystallinity of the interface can be improved by minimizing the GaN growth rate of the superlattice layer 130. That is, when Fe (iron) doping is used, a new trap formed by the Fe dopant is maintained while maintaining high-quality crystallinity due to the inherent low-speed growth of GaN, thereby obtaining a semi-insulating effect and reducing the leakage current more efficiently It can have an advantage.

According to an embodiment disclosed herein, the concentration of the p-type dopant may be 1e ¹⁶ / cm ³ to 5e ²⁰ / cm ³ . In particular, the concentration of the p-type dopant may be 3e ¹⁷ / cm ³ to 1e ²⁰ / cm ³ .

Also, according to one embodiment, the concentration of the p-type dopant may be gradually decreased in the stacking direction of the superlattice layer 130. For example, the concentration of the p-type dopant may be continuous and gradually decrease. Also, for example, the concentration of the p-type dopant may be gradually decreased stepwise.

In other words, the p-type dopant may be doped based on a doping profile indicating a doping amount with respect to the p-type dopant in the stacking direction of the superlattice layer 130.

Here, the doping profile may be a doping profile in which the doping amount of the p-type dopant is reduced to a specific slope from a specific position of the superlattice layer 130 in the stacking direction.

In addition, the doping profile may be a doping profile in which the doping amount of the p-type dopant is decreased stepwise (or stepwise) from a specific position of the superlattice layer 130 in the stacking direction.

Also, according to one embodiment, the doping amount of the p-type dopant may be less than the minimum doping amount from the upper portion of the superlattice layer 130 to a specific depth.

The specific depth may be from 2 nm to 50 nm. The minimum doping amount may be 1e ¹⁶ / cm ³ to 1e ¹⁷ / cm ³ .

3 is a graph illustrating the doping profile of an Fe dopant according to one embodiment disclosed herein.

3 shows a case where the p-type dopant is Fe.

Referring to FIG. 3, a doping profile for the Fe doping concentration in the superlattice layer 130 can be confirmed.

It can be confirmed that the Fe doping concentration is continuously and gradually decreased from the second point P2 to the first point P1 in the superlattice layer 130. [

According to one embodiment, the Fe doping concentration at the second point P2 may be 5e ²⁰ / cm ³ .

Further, according to one embodiment, the doping concentration of the Fe in said first point (P1) may be 1e ¹⁶ / cm ³ days.

In addition, according to an exemplary embodiment, the amount from the top of the superlattice layer 130 to a specific depth? 1 may be less than the minimum doping amount. For example, the specific depth? 1 may be 2 nm to 50 nm, and FIG. 3 shows a case where the specific depth? 1 is 50 nm.

4 is a graph depicting the doping profile of an Fe dopant according to another embodiment disclosed herein.

Fig. 4 shows a case where the p-type dopant is Fe.

Referring to FIG. 4, the doping profile for the Fe doping concentration in the superlattice layer 130 can be confirmed.

It can be seen that the Fe doping concentration is gradually decreased stepwise from the sixth point to the third point P6 to P3 in the superlattice layer 130. [

As in FIG. 3, the Fe doping concentration at the sixth point P6 may be 5e ²⁰ / cm ³ and the Fe doping concentration at the third point may be 1e ¹⁶ / cm ³ .

In addition, from the upper portion of the superlattice layer 130 to the specific depth? 1, the doping amount may be less than the minimum doping amount. For example, the specific depth? 1 may be 2 nm to 50 nm, and FIG. 4 shows a case where the specific depth? 1 is 50 nm.

Referring again to FIG. 2, the GaN layer 140 may have a thickness of 0.5 um to 4.0 um. In particular, the thickness of the GaN layer 140 may be 1 um to 3 um.

The GaN layer 140 may be formed in various manners (or methods). For example, the GaN layer 140 may be formed by selectively growing a nitride semiconductor crystal. The GaN layer 140 may be formed by a metal organic vapor phase epitaxy (MOCVD) method, a molecular beam epitaxial growth method (MBE) HVPE). ≪ / RTI > However, considering the crystallinity of the GaN layer 140, MOCVD may be used for device fabrication.

According to one embodiment, the semiconductor device 100 may include a high-resistance layer for exhibiting semi-insulating characteristics of a GaN channel formed by implanting at least one dopant of C, Fe, and Mg dopants on the GaN layer 140. [ A GaN layer (not shown). Here, the concentration of the at least one dopant may be at least one of Mg, C, and Fe. The concentration of the at least one dopant may be 1e ¹⁶ / cm ³ to 5e ²⁰ / cm ³ . In particular, the concentration of the at least one dopant may be 3e ¹⁷ / cm ³ to 1e ²⁰ / cm ³ .

According to one embodiment, the GaN layer 140 may include a plurality of layers of GaN grown at different temperatures.

Also, according to one embodiment, the number of the plurality of layers made of GaN grown at different temperatures may be 2 to 5.

The AlGaN barrier layer 150 may be formed on the GaN layer 140. The AlGaN barrier layer 150 may serve as an active layer.

The thickness of the AlGaN barrier layer 150 may range from 1 nm to 100 nm, and the thickness of the AlGaN barrier layer 150 may range from 5 nm to 50 nm.

The AlGaN barrier layer 150 may have a variety of compositions. For example, the composition of Al in the AlGaN barrier layer 150 may be 10% to 30%. It is apparent to those skilled in the art that the AlGaN barrier layer 150 may be formed with various composition ratios.

The AlGaN barrier layer 150 may be formed in a variety of ways (or methods). For example, the AlGaN barrier layer 150 may be formed by selectively growing a nitride semiconductor crystal. The AlGaN barrier layer 150 may be formed by a metal organic vapor phase epitaxy (MOCVD), a molecular beam epitaxy (MBE) (HVPE). ≪ / RTI > However, considering the crystallinity of the AlGaN barrier layer 150, MOCVD may be used for device fabrication.

The GaN cap layer is formed on the AlGaN barrier layer 150 and may be formed by growing GaN thinly.

According to one embodiment, the thickness of the GaN cap layer may be in the range of 0 nm to 100 nm, particularly 2 nm to 10 nm. The GaN cap layer may serve to prevent surface leakage current.

The source electrode 170, the drain electrode 180, and the gate electrode 160 may be formed on a part of the AlGaN barrier layer 150. In addition, when the semiconductor device 100 further includes the GaN cap layer, the semiconductor device 100 may be formed on a part of the GaN cap layer.

As described above, a 2DEG (CDEG) current flowing from the drain electrode to the source electrode may occur through control of a schottky gate electrode.

According to one embodiment, the semiconductor device 100 is formed on a portion of the AlGaN barrier layer 150, the source electrode 170, the drain electrode 180, and the gate electrode 160 And may further include an oxide layer 190.

In addition, when the semiconductor device 100 further includes the GaN cap layer, the oxide layer 190 may be formed on a part of the GaN cap layer.

The oxide layer 190 may reduce surface leakage current.

The oxide layer 190 may be formed between the source electrode 170 or the drain electrode 180 and the gate electrode 160.

The oxide layer 190 may have a variety of materials or composition ratios. For example, the oxide layer 190 may be formed of at least one of SiO 2, Si _x N _y (for example, Si 3 N 4), HfO 2, Al 2 O 3, ZnO, and Ga 2 O 3.

According to one embodiment, the thickness of the oxide layer 190 may be in the range of 2 nm to 200 nm, particularly 2 nm to 100 nm.

For example, the oxide layer may be formed by a metal organic chemical vapor deposition (MOCVD) method, a molecular beam epitaxy (MBE) method, a helium vapor deposition (HVPE) method, , Plasma-enhanced chemical vapor deposition (PECVD), sputtering, and atomic layer deposition (ALD).

The work disclosed herein In the embodiment  Description of a method of manufacturing a semiconductor device according to

A method of manufacturing a semiconductor device according to an embodiment disclosed herein may be implemented as a part or a combination of the constituent elements or steps included in the embodiments described above or a combination of the embodiments, Overlapping portions may be omitted for clarity of the method of manufacturing a semiconductor device according to an embodiment.

A method of fabricating a semiconductor device according to an embodiment disclosed herein includes forming an AlN layer on a substrate, forming an AlGaN buffer layer on the AlN layer, forming a superlattice layer on the AlGaN buffer layer Forming a GaN layer on the superlattice layer, and forming an AlGaN barrier layer on the GaN layer.

According to one embodiment, at least one of the AlN layer, the AlGaN buffer layer, the superlattice layer, the GaN layer, and the AlGaN barrier layer may be formed by metal organic chemical vapor deposition (MOCVD), molecular beam epitaxy (MBE) (HVPE), plasma-enhanced chemical vapor deposition (PECVD), sputtering, and atomic layer deposition (ALD).

5 is a flowchart showing a method of manufacturing a semiconductor device according to an embodiment disclosed herein.

Referring to FIG. 5, a method of manufacturing a semiconductor device according to an embodiment disclosed herein may include the following steps.

First, an AlN layer may be formed on a substrate (S110).

Next, an AlGaN buffer layer may be formed on the AlN layer (S120).

Next, a superlattice layer may be formed on the AlGaN buffer layer (S130).

Next, a GaN layer may be formed on the superlattice layer (S140).

Next, an AlGaN barrier layer may be formed on the GaN layer (S150).

6A to 6E are views showing an example of a method of manufacturing a semiconductor device according to an embodiment disclosed in this specification.

6A to 6E, a method of manufacturing a semiconductor device according to an embodiment disclosed herein includes sequentially forming an AlN layer 110, an AlGaN buffer layer 120, a superlattice layer 130, A GaN layer 140 and an AlGaN barrier layer 150 may be formed.

The method for fabricating a semiconductor device according to an embodiment disclosed herein may include forming a gate electrode 160, a source electrode 170, and a drain electrode 180 on a part of the AlGaN barrier layer 150 As shown in FIG.

The method of manufacturing a semiconductor device according to an embodiment disclosed herein may further include the step of forming a gate electrode 160 on the AlGaN barrier layer 150, the source electrode 170, the drain electrode 180, And forming an oxide film layer 190 on the substrate.

6A to 6E, the AIN layer 110 can be formed (or grown) with the MOCVD thin film growth equipment on the substrate 101 (FIG. 7A).

The substrate 101 may be n-type or p-type, and the substrate may be Si, SiC, Sapphire, GaN (e.g., Freestanding GaN) substrate or the like.

The AIN layer 110 may be a single layer (or a layer) or may be grown in two to five different temperatures.

TMAl can be used as a raw material of AlN, and NH3 can be used as a raw material of N. [

According to one embodiment, the AlN layer (110, or AlN nucleation layer) can be used in combination of low temperature and high temperature. That is, the lower portion of the AlN buffer may be formed by the low-temperature growth, and the upper portion of the AlN buffer may be formed by the high-temperature growth (see the first AlN layer and the second AlN layer described above).

(TMGa), trimethyl aluminum (TMAl), and ammonia (NH3) are used as a raw material, and a high temperature III-V thin film can be formed by being synthesized in the environment of the electron transporting layer and growing into an epitaxial layer. The nucleation layer of the conventional method for GaN growth can be grown according to the prepared substrate.

Next, an AlGaN buffer layer 120 may be formed on the AlN layer 110 (FIG. 6B)

According to one embodiment, an AlGaN buffer layer 120 having a single or two to five different Al compositions may be grown on the AIN layer 110. The Al composition of each of the AlN layer 110 and the AlGaN buffer layer 120 may be sequentially grown to a range of 1 to 70% or a single layer, and each layer may have a thickness ranging from 0.1 to 3.0 μm.

The AlGaN buffer layer 120 may have a graded or graded graded buffer structure ranging from a layer having a higher Al composition to a layer having a lower Al composition at the lower layer.

That is, the Al composition of the AlGaN buffer layer may be represented by Al _x Ga _{1 - x} N (0 _{? X} ? 1), and the composition of Al is continuous, gradually decreased, or stepwise (or stepwise) (See Figures 3 to 4).

Next, a superlattice layer 120 may be formed on the AlGaN buffer layer 120 (FIG. 6C).

Specifically, the superlattice layer 130 may be formed by stacking a plurality of superlattice thin film layers 133 in which two different first thin film layers 131 and second thin film layers 132 are stacked.

In other words, the superlattice layer 130 may be formed by alternately stacking a first thin film layer 131 and a second thin film layer 132, which are two different thin film layers.

The superlattice thin film layer 133 may be formed of various materials. For example, the superlattice thin film layer 133 may include at least one of AlN / GaN and AlGaN / GaN superlattice structures.

That is, according to one embodiment, the first thin film layer 131 may be made of AlN or AlGaN, and the second thin film layer 132 may be made of GaN.

Further, this may mean that the two different thin film layers 131 and 132 are each formed of a combination of AlN / GaN or AlGaN / GaN. It is apparent to those skilled in the art that the superlattice thin film layer 133 may be formed of various materials.

Also, according to one embodiment, the thickness of the first thin film layer 131 may be 1 nm to 20 nm.

In addition, according to one embodiment, the thickness of the second thin film layer 132 may be 10 nm to 70 nm.

Also, according to one embodiment, the number of superlattice thin film layers 133 stacked in the superlattice layer 130 may be 60-120.

That is, the superlattice layer 130 may include 60 to 120 superlattice thin film layers 133. In other words, the superlattice layer 130 may include two different thin film layers 131 and 132 of 60 to 120 pairs. In other words, the superlattice layer 130 may be formed by stacking the two different thin film layers 131 and 132 alternately from 119 to 239 times.

In the super lattice layer 130, the Al composition ratio of AlGaN may be 50% to 99%, and the total thickness of AlN and GaN or the superlattice layer 130 of AlGaN and GaN may be 0.3 ~ It can be grown to 4.0 um.

The superlattice layer 130 may be formed in a variety of ways (or methods). For example, the superlattice layer 130 may be formed by selectively growing a nitride semiconductor crystal. The superlattice layer 130 may be formed by a metal organic vapor phase epitaxy (MOCVD), a molecular beam epitaxy (MBE) (HVPE). ≪ / RTI > However, considering the crystallinity of the superlattice layer 130, MOCVD may be used for device fabrication.

According to one embodiment disclosed herein, the superlattice buffer structure (or superlattice layer 130) may be doped with a specific dopant to have a semi-insulating property.

According to one embodiment, the specific dopant may be a p-type dopant. For example, the p-type dopant may be at least one of Mg, C, and Fe.

According to an embodiment disclosed herein, the concentration of the p-type dopant may be 1e ¹⁶ / cm ³ to 5e ²⁰ / cm ³ . In particular, the concentration of the p-type dopant may be 3e ¹⁷ / cm ³ to 1e ²⁰ / cm ³ .

Also, according to one embodiment, the concentration of the p-type dopant may be gradually decreased in the stacking direction of the superlattice layer 130. For example, the concentration of the p-type dopant may be continuous and gradually decrease. Also, for example, the concentration of the p-type dopant may be gradually decreased stepwise.

Next, a GaN layer 140 may be formed on the superlattice layer 130 (FIG. 6D).

GaN constituting the GaN layer 140 may be formed by an organic metal vapor phase growth method called MOCVD.

In this case, the GaN layer 140 may be formed by epitaxial growth by synthesizing NH ₃ , which is a raw material of Ga, as a raw material of Ga, NH ₃ in a reactor at a high temperature.

The GaN layer 140 may have a thickness of 0.5 to 4.0 um. In particular, the thickness of the GaN layer 140 may be 1 um to 3 um.

Here, the GaN layer 140 may be doped with Fe, Mg or Carbon to form a semi-insulating property. The GaN layer 140 may also be grown at one temperature or two to five continuous or discontinuous temperatures.

Next, after the GaN layer 140 is grown, an AlGaN barrier layer 150, which is an active layer for forming a hetero-junction 2DEG layer, is grown with an Al composition ratio of 10% to 30%, and the AlGaN barrier layer 150 is grown. The source electrode 170, the drain electrode 180 and the gate electrode 160 may be formed on the AlGaN barrier layer 150, the source electrode 170, the drain electrode 180, And an oxide layer 190 may be formed on a portion of the gate electrode 160 (FIG. 6E).

The thickness of the AlGaN barrier layer 150 may be between 5 nm and 50 nm. In particular, the AlGaN barrier layer 150 may have a thickness of 10 nm to 30 nm.

The AlGaN barrier layer 150 forms a 2DEG due to a piezo-polarization due to a difference in lattice constant between the AlGaN barrier layer 150 and the GaN layer 140. The 2DEG density can be determined according to the Al composition and thickness.

Deposition of the source electrode 170, the drain electrode 180, and the gate electrode 160 may be performed using an E-beam.

According to an embodiment disclosed herein, a semiconductor device having improved threshold voltage characteristics and leakage current characteristics through sequentially stacked AlN layers (or AlN nucleation layers), AlGaN buffer layers, and superlattice layer structures, and a method of manufacturing the same .

In particular, according to one embodiment disclosed herein, a buffer layer (or a buffer layer) or a buffer layer constructed in comparison with a buffer combination through an AlN layer (or AlN nucleation layer) sequentially stacked, an AlGaN buffer layer and a superlattice layer structure There is an advantage that a semiconductor device having excellent threshold voltage characteristics and leakage current characteristics and a manufacturing method thereof can be provided.

Specifically, according to the semiconductor device disclosed in the present specification, by providing a semiconductor device having a sequentially stacked AlN layer (or AlN nucleation layer), an AlGaN buffer layer, and a superlattice layer structure, and a manufacturing method thereof, Leakage current is reduced and insertion of AlN layer with lower thermal expansion coefficient than AlGaN may be advantageous in reducing the probability of cracking during cooling down.

The scope of the present invention is not limited to the embodiments disclosed herein, and the present invention can be modified, changed, or improved in various forms within the scope of the present invention and the claims.

100: semiconductor device 101: substrate
110: AlN layer 120: AlGaN buffer layer
130: superlattice layer 140: GaN layer
150: AlGaN barrier layer

Claims (32)

AlN layer;
An AlGaN buffer layer formed on the AlN layer;
A superlattice layer formed on the AlGaN buffer layer;
A GaN layer formed on the superlattice layer; And
And an AlGaN barrier layer formed on the GaN layer. The method of claim 1, wherein the AlN layer
And a plurality of layers of AlN grown at different temperatures. 3. The method according to claim 2, wherein the number of the plurality of layers made of AlN grown at the different temperatures,
2 < / RTI > The method of claim 1, wherein the AlN layer
A first AlN layer grown at a low temperature; And
And a second AlN layer formed on the first AlN layer and grown at a high temperature. The method of claim 1, wherein the AlGaN buffer layer comprises:
And a plurality of layers made of AlGaN having different compositions of Al. 6. The method according to claim 5, wherein the number of the plurality of layers made of AlGaN,
2 < / RTI > The method according to claim 1, wherein the Al composition of at least one of the AlN layer and the AlGaN buffer layer,
1% to 70%. The method according to claim 1, wherein the Al composition of at least one of the AlN layer and the AlGaN buffer layer,
And is gradually decreased in the stacking direction. The method as claimed in claim 1, wherein the thickness of at least one of the AlN layer and the AlGaN buffer layer,
0.1 um to 3.0 um. The method of claim 1, wherein the thickness of the superlattice layer
0.3 um to 4.0 um. The method of claim 1, wherein the superlattice layer
Wherein a plurality of superlattice thin film layers in which two different first thin film layers and second thin film layers are stacked is formed. 14. The method according to claim 13, wherein the first thin film layer
AlN or AlGaN,
The second thin film layer
GaN. 13. The method of claim 12, wherein the composition of Al contained in the first thin film layer
50% to 99%. The method according to claim 12, wherein the thickness of the first thin film layer
1 nm to 20 nm. 13. The method according to claim 12, wherein the thickness of the second thin film layer
And is 10 nm to 70 nm. 13. The method of claim 12, wherein the number of the superlattice thin film layers
Lt; RTI ID = 0.0 > 60 < / RTI > The method of claim 1, wherein the superlattice layer
and doped with a p-type dopant. 18. The method of claim 17, wherein the p-
Mg, C, and Fe. 18. The method of claim 17, wherein the concentration of the p-
1e ¹⁶ / cm ³ to 5e ²⁰ / cm ³ . 18. The method of claim 17, wherein the concentration of the p-
And the thickness of the superlattice layer is gradually decreased in the stacking direction of the superlattice layer. The GaN substrate according to claim 1,
0.5 um to 4.0 um. The GaN substrate according to claim 1,
Mg, < / RTI > C and Fe. 23. The method of claim 22, wherein the at least one dopant concentration is selected from the group consisting of:
1e ¹⁶ / cm ³ to 5e ²⁰ / cm ³ . The GaN substrate according to claim 1,
And a plurality of layers made of GaN grown at different temperatures. 25. The method of claim 24, wherein the number of the plurality of layers of GaN grown at different temperatures,
2 < / RTI > 2. The nitride semiconductor device according to claim 1, wherein the composition of Al in the AlGaN barrier layer is,
10% to 30%. 2. The method of claim 1, wherein the thickness of the AlGaN barrier layer
And is 5 nm to 50 nm. The method of claim 1, wherein the AlN layer
And is formed on a substrate. 29. The method of claim 28,
Si, SiC, Sapphire, and GaN. The method according to claim 1,
Further comprising a source electrode, a drain electrode, and a gate electrode formed on a part of the AlGaN barrier layer. Forming an AlN layer on the substrate;
Forming an AlGaN buffer layer on the AlN layer;
Forming a superlattice layer on the AlGaN buffer layer;
Forming a GaN layer on the superlattice layer; And
And forming an AlGaN barrier layer on the GaN layer. 32. The method of claim 31,
At least one of the AlN layer, the AlGaN buffer layer, the superlattice layer, the GaN layer, and the AlGaN barrier layer,
At least one of metal organic chemical vapor deposition (MOCVD), molecular beam epitaxy (MBE), helium vapor deposition (HVPE), plasma enhanced chemical vapor deposition (PECVD), sputtering, and atomic layer deposition Wherein the semiconductor device is formed on the basis of a predetermined pattern.

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