High-quality GaN HEMT power semiconductor epitaxial wafer with 3D nitride structure and manufacturing method thereof

Abstract

The invention relates to a high-quality GaN HEMT power semiconductor epitaxial wafer with a 3D nitride structure and a manufacturing method of the high-quality GaN HEMT power semiconductor epitaxial wafer. The embodiment of the invention provides a high-quality GaN HEMT (High Electron Mobility Transistor) power semiconductor epitaxial wafer with a three-dimensional nitride structure. The high-quality GaN HEMT power semiconductor epitaxial wafer comprises a growth substrate; a nucleation region formed on the growth substrate; and a three-dimensional nitride structure region formed on the nucleation region and having a composition ratio that varies in the lateral direction.

Description

Technical Field

[0001] The present invention relates to a GaN HEMT power semiconductor epitaxial wafer and a method for manufacturing the GaN HEMT power semiconductor epitaxial wafer, wherein a three-dimensional nitride structure is introduced to improve heat dissipation characteristics and epitaxial crystal quality. Background Art

[0002] The GaN HEMT epitaxial wafer is manufactured by depositing a film on an electrically insulating silicon carbide (SiC) or silicon (Si) substrate with high heat transfer properties. The GaN HEMT epitaxial wafer is used as a core component of a power amplifier, which is a key component of a radio frequency communication module, and as a key material for converters and inverters for high-speed switching.

[0003] GaN HEMT devices generate a lot of heat during operation, which has a significant impact on device reliability and lifespan, as well as module quality. Therefore, solutions and technologies to enhance heat dissipation are necessary.

[0004] Conventional HEMTs (high electron mobility transistors) for GaN power semiconductors known to date have a structure in which an AlN nucleation region, an Al(1-x)Ga(x)N stress control region, a GaN buffer region, a GaN channel region, and an Al(1-x)Ga(x)N barrier region are stacked on a SiC or Si growth substrate.

[0005] The GaN buffer region forms a high-resistance layer to reduce vertical leakage current. To this end, the buffer region is intentionally doped with iron (Fe) or carbon (C). However, doping with impurities such as iron (Fe) or carbon (C) has the problem of deteriorating the film formation quality in the GaN buffer region.

[0006] Therefore, since the thickness of the conventional GaN HEMT device increases, there is a problem in that the heat dissipation characteristics of the GaN HEMT device are deteriorated and the device characteristics are degraded.

[0007] As a method of forming a high heat dissipation GaN HEMT device, minimizing the thickness is desired, but in doing so, there remains the task of achieving a thin GaN HEMT device structure while solving the problem of degradation of crystal quality due to thickness reduction. Summary of the Invention

[0008] Technical issues

[0009] The present invention aims to provide a high-quality GaN HEMT power semiconductor epitaxial wafer having a three-dimensional nitride structure and a method for manufacturing the same. The three-dimensional nitride structure can minimize the heat generated during operation of the GaN HEMT device, or can quickly and easily release the generated heat to improve the reliability, lifespan and module quality of the device.

[0010] Technical Solution

[0011] According to an embodiment of the present invention, a high-quality GaN HEMT power semiconductor epitaxial wafer with a three-dimensional nitride structure is provided. The high-quality GaN HEMT power semiconductor epitaxial wafer with a three-dimensional nitride structure includes: a growth substrate; a nucleation region formed on the growth substrate; and a three-dimensional nitride structure region formed on the nucleation region and having a composition ratio that varies along a lateral direction.

[0012] In an embodiment of the present invention, the thickness of the three-dimensional nitride structure region is 100 nm or less.

[0013] In an embodiment of the present invention, a composition ratio change trend occurring along the lateral direction of the three-dimensional nitride structure region is similar to a wave curve with a period of 100 nm or less.

[0014] In an embodiment of the present invention, the growth substrate is SiC or Si, the nucleation region is AlN, and the three-dimensional nitride structure region is formed of AlInGaN.

[0015] According to an embodiment of the present invention, the structure further includes: a channel region formed of GaN on the three-dimensional nitride structure region; and a barrier region formed of AlInGaN or AlScGaN on the channel region.

[0016] According to an embodiment of the present invention, a method for manufacturing a high-quality GaN HEMT power semiconductor epitaxial wafer having a three-dimensional nitride structure is provided, the method comprising the following steps: preparing a growth substrate; forming a nucleation region on the growth substrate; and using a precursor cluster to form a three-dimensional nitride structure region having a composition ratio that changes along a lateral direction, wherein the elements of the nitride material in the precursor cluster are concentrated on the nucleation region.

[0017] In an embodiment of the manufacturing method according to the present invention, the step of forming the three-dimensional nitride structure region may be repeatedly performed two or more times.

[0018] In an embodiment of the manufacturing method according to the present invention, the step of forming the three-dimensional nitride structure region includes the following steps: forming a three-dimensional nitride structure as a precursor cluster having a three-dimensional shape by aggregating the group III elements (Al, Ga, In) of the nitride material with each other without supplying a nitrogen source on the nucleation region; and forming 3DNS, wherein a nitrogen source is supplied to the three-dimensional nitride structure to form the three-dimensional nitride structure region in which the three-dimensional nitride structure is recrystallized into a single crystal.

[0019] In an embodiment of the manufacturing method according to the present invention, the step of forming the three-dimensional nitride structure is formed by pre-flowing a source of the group III element (Al, Ga, In) of the nitride material to form the three-dimensional nitride structure, and the step of forming 3DNS is formed by supplying ammonia (NH3) gas to form a recrystallized three-dimensional nitride structure region.

[0020] In an embodiment of the manufacturing method according to the present invention, the method may further include the following step: forming a device region (active region) including a channel region and a barrier region on the three-dimensional nitride structure region.

[0021] Beneficial effects

[0022] According to the present invention, the lattice constant difference between the nucleation region and the channel region is reduced by the three-dimensional nitride structure (or structured region). In addition, crystal defects such as dislocations are offset and eliminated. Therefore, the three-dimensional nitride structure plays a role in improving crystal quality.

[0023] According to the present invention, the quality of the channel region grown through subsequent processes is improved by the three-dimensional nitride structure (or structured region). In addition, the HEMT epitaxial structure can be made ultra-thin. Therefore, it is possible to produce HEMT devices with high heat dissipation. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 is a diagram showing an embodiment of a high-quality GaN HEMT power semiconductor epitaxial wafer by introducing a three-dimensional nitride structure according to the present invention.

[0025] Figure 2 yes Figure 1 An enlarged photograph of region A in a cross section of a high-quality GaN HEMT power semiconductor epitaxial wafer actually manufactured by introducing a three-dimensional nitride structure.

[0026] Figures 3 to 7 FIG. 1 is a diagram illustrating an embodiment of a method for manufacturing a high-quality GaN HEMT power semiconductor epitaxial wafer by introducing a three-dimensional nitride structure according to the present invention. DETAILED DESCRIPTION

[0027] Hereinafter, embodiments of a high-quality GaN HEMT power semiconductor epitaxial wafer having a 3D nitride structure and a method for manufacturing the same according to the present invention will be described in detail with reference to the accompanying drawings.

[0028] The terms used below are selected for convenience of explanation and should be appropriately interpreted as meanings consistent with the technical concept of the present invention without being limited to dictionary meanings.

[0029] Reference Figure 1 According to the embodiment, a high-quality GaN HEMT power semiconductor epitaxial wafer with a three-dimensional nitride structure includes a growth substrate (110), a nucleation region (120) and a three-dimensional nitride structure region (130). Figure 2 yes Figure 1 An enlarged photograph of region A in a cross section of a high-quality GaN HEMT power semiconductor epitaxial wafer actually manufactured by introducing a three-dimensional nitride structure.

[0030] The growth substrate (110) is preferably formed of SiC or Si, and the nucleation region (120) is preferably formed of AlN on the growth substrate.

[0031] A three-dimensional nitride structure region (130) is formed on the nucleation region (120) and is formed such that a composition ratio (C) changes along a lateral direction (L).

[0032] At this time, the three-dimensional nitride structure region (130) is formed as a discontinuous and non-uniform nanoscale dot structure, and the positions of these dot structures are formed at a different composition ratio from other positions.

[0033] That is, the three-dimensional nitride structure region (130) formed of Al(x)In(y)Ga(1-xy)N has a technical characteristic of being formed so that x and y are different in the lateral direction.

[0034] This embodiment can improve the epitaxial crystal quality of the channel region formed of GaN material thereon by using a three-dimensional nitride structure region.

[0035] The three-dimensional nitride structure region helps alleviate the thermomechanical stress caused by the lattice constant difference between the AlN nucleation region and the GaN channel region. It also cancels and eliminates crystal defects such as dislocations, thereby improving crystal quality.

[0036] This embodiment further includes a channel region (140) formed of GaN material on the three-dimensional nitride structure region through subsequent post-processing, and a barrier region (150) formed of AlGaN material on the channel region.

[0037] The three-dimensional nitride structure region ensures that the GaN channel region grown thereon has high quality, thereby making it possible to manufacture a GaN HEMT device with high heat dissipation by making the GaN HEMT epitaxial structure ultra-thin to less than 700nm thick.

[0038] At this time, the three-dimensional nitride structure region according to the present embodiment is preferably formed to have a thickness of 3 nm or more.

[0039] Preferably, the three-dimensional nitride structure region (130) according to the present embodiment is formed so that a composition ratio change trend appearing in a lateral direction approximates a wave curve having a period of 100 nm or less.

[0040] In this embodiment, the three-dimensional nitride structure region (130) performs the following five main functions.

[0041] First, it controls the thermomechanical stress at the interface caused by the lattice constant mismatch and the difference in thermal expansion coefficient between the nucleation region (120) and the channel region (140).

[0042] Second, it eliminates crystal defects and surface defects caused at the interface between the nucleation region (120) and the channel region (140).

[0043] Third, it provides a high heat dissipation solution that can maintain the high heat dissipation characteristics of the growth substrate (110).

[0044] Fourth, it minimizes crystal defects when growing a GaN HEMT epitaxial structure with an ultra-thin thickness of 500 nm or less, thereby ensuring high-quality GaN channel regions and AlInGaN or AlScGaN barrier regions.

[0045] Fifth, by removing the iron (Fe) or carbon (C)-doped GaN buffer region in conventional GaN HEMT devices, device characteristics can be maximized.

[0046] The mechanism for the main function of the three-dimensional nitride structure region (130) can be explained as follows.

[0047] When forming the three-dimensional nitride structure region (130), a metal organic source of group III elements (Al, Ga, In) constituting the nitride material or a [Mg] or [Si] source used as a group III nitride dopant is pre-flowed without supplying ammonia (NH3) gas.

[0048] At this time, through pyrolysis reaction, the group III elements (Al, Ga, In) form a three-dimensional nitride structure (which is a three-dimensional point cluster) around the surface (unstable surface with high thermodynamic energy) that satisfies the threading dislocation, which is a crystal defect generated from the interface between the growth substrate (110) and the nucleation region (120).

[0049] As the surface energy of the nucleation region (120) is lowered by the three-dimensional nitride structure, crystallization proceeds by supplying ammonia (NH3) gas, thereby producing a thermodynamically stable state surface.

[0050] This process is repeated one or more times to form a three-dimensional structure region, that is, to arbitrarily control the change trend of the above-mentioned composition ratio, and this can be changed according to the thickness and composition of the channel region (140) and the barrier region (150) grown in the subsequent process.

[0051] Next, according to Figures 3 to 7 According to the present embodiment, the method for manufacturing a high-quality GaN HEMT power semiconductor epitaxial wafer with a 3D nitride structure includes a step of preparing a growth substrate (S100), a step of forming a nucleation region on the growth substrate (S200), and a step of forming a three-dimensional nitride structure region (S300).

[0052] The step (S100) of preparing a growth substrate prepares a growth substrate (110) for forming a nucleation region.

[0053] The step (S200) of forming a nucleation region forms a nucleation region (120) on a growth substrate (110).

[0054] Next, the step of forming a three-dimensional nitride structure region (S300) forms a three-dimensional nitride structure region (130) whose composition ratio changes along the lateral direction by using precursor clusters of group III elements (Al, Ga, In) of nitride materials gathered on the surface of the nucleation region (120).

[0055] The method of forming the three-dimensional nitride structure region (130) using the above-mentioned precursor cluster can be broadly divided into two steps.

[0056] Preferably, the step of forming a three-dimensional nitride structure region ( S300 ) includes the step of forming a three-dimensional nitride structure ( S310 ) and the step of forming a 3DNS ( S320 ).

[0057] In the step (S310) of forming a three-dimensional nitride structure, group III elements (Al, Ga, In) of the nitride material are first gathered to form a three-dimensional nitride structure (131a) on the nucleation region (120), which is a three-dimensional precursor cluster.

[0058] The three-dimensional nitride structure (131a) may be formed by pre-flowing group III elements including Al, In, and Ga.

[0059] The three-dimensional nitride structure (131a) can be formed by pre-flowing a metal organic source of a group III element (Al, Ga, In) constituting a nitride material through a pyrolysis reaction without supplying ammonia (NH3) gas.

[0060] Next, the step of forming 3DNS (S320) supplies a nitrogen source including ammonia (NH3) to the three-dimensional nitride structure to form a three-dimensional nitride structure region (130), wherein the three-dimensional nitride structure is recrystallized into a single crystal.

[0061] At this time, each of the three-dimensional nitride structures (131a) forms the aforementioned nanoscale dots within the three-dimensional nitride structure region (130).

[0062] Generally, the epitaxial process performs source pre-flow, in which all elements constituting a thin film to be grown, including organic metals and gases, flow into a reaction chamber in advance, and then performs main growth including initial growth (nucleation) and layer growth.

[0063] In contrast, the manufacturing method according to the present embodiment first pre-flows the group III elements except the nitrogen source including ammonia (NH3), thereby first forming a three-dimensional nitride structure (131a), which is a precursor cluster having a three-dimensional shape as described above.

[0064] Next, by flowing a nitrogen source into the reaction chamber, recrystallization may be performed, thereby forming the above-mentioned three-dimensional nitride structure region.

[0065] In the manufacturing method according to the present embodiment, the step ( S300 ) of forming the three-dimensional nitride structure region may be repeated two or more times.

[0066] Thus, the thickness increase and the composition change trend of the three-dimensional nitride structure region in the lateral direction can be changed, thereby achieving the five functional enhancements of the three-dimensional nitride structure region.

[0067] In addition, the manufacturing method according to the present embodiment includes a step (S400) of forming a device region including a channel region (140) made of gallium nitride (GaN) as a material and a barrier region (150) made of AlGaN or AlScGaN as a material on the three-dimensional nitride structure region (130).

Claims

1. A high-quality GaN HEMT power semiconductor epitaxial wafer having a three-dimensional nitride structure, the high-quality GaN HEMT power semiconductor epitaxial wafer having a three-dimensional nitride structure comprising: Growth substrate; a nucleation region formed on the growth substrate; as well as A three-dimensional nitride structure region is formed on the nucleation region and has a composition ratio that varies along a lateral direction.

2. The high-quality GaN HEMT power semiconductor epitaxial wafer with a three-dimensional nitride structure according to claim 1, wherein: The thickness of the three-dimensional nitride structure region is 100 nm or less.

3. The high-quality GaN HEMT power semiconductor epitaxial wafer with a three-dimensional nitride structure according to claim 1, wherein: A composition ratio change trend occurring along the lateral direction of the three-dimensional nitride structure region is similar to a wave curve with a period of 100 nm or less.

4. The high-quality GaN HEMT power semiconductor epitaxial wafer with a three-dimensional nitride structure according to claim 1, wherein: The growth substrate is SiC or Si, the nucleation region is AlN, and the three-dimensional nitride structure region is formed of AlInGaN.

5. The high-quality GaN HEMT power semiconductor epitaxial wafer with a three-dimensional nitride structure according to claim 4, further comprising: a channel region formed of GaN on the three-dimensional nitride structure region; as well as A barrier region is formed of AlInGaN or AlScGaN on the channel region.

6. A method for manufacturing a high-quality GaN HEMT power semiconductor epitaxial wafer having a three-dimensional nitride structure, the method comprising the following steps: preparing a growth substrate; forming a nucleation region on the growth substrate; as well as A three-dimensional nitride structure region having a composition ratio that changes in a lateral direction is formed using a precursor cluster in which elements of the nitride material are concentrated on the nucleation region.

7. The method according to claim 6, wherein: The step of forming the three-dimensional nitride structure region can be repeatedly performed two or more times.

8. The method according to claim 6, wherein: The step of forming the three-dimensional nitride structure region comprises the following steps: forming a three-dimensional nitride structure as a precursor cluster having a three-dimensional shape by aggregating the group III elements Al, Ga, and In of the nitride material with each other without supplying a nitrogen source on the nucleation region; and A 3DNS is formed, wherein a nitrogen source is supplied to the three-dimensional nitride structure to form a region of the three-dimensional nitride structure in which the three-dimensional nitride structure is recrystallized into a single crystal.

9. The method according to claim 8, wherein The step of forming the three-dimensional nitride structure forms the three-dimensional nitride structure by pre-flowing sources of group III elements Al, Ga, and In of the nitride material, and The step of forming 3DNS forms a recrystallized three-dimensional nitride structure region by supplying ammonia NH 3 gas.

10. The method according to claim 6, further comprising the steps of: A device region including a channel region and a barrier region is formed on the three-dimensional nitride structure region.

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