CN217444336U - Based on ScAlMgO 4 GaN epitaxial structure of substrate - Google Patents

Abstract

The utility model discloses a based on ScAlMgO ₄ GaN epitaxial structure of substrate comprising ScAlMgO stacked in sequence ₄ The substrate, the buffer layer, the island growth layer of GaN 3D, the stratiform growth layer of GaN 2D and HT-GaN growth layer. Compared with the prior art, the utility model discloses can obviously reduce the defect density of gaN film, obtain high-quality gaN epitaxial structure, and the manufacturing process is simpleSimple and easy operation.

Description

Based on ScAlMgO 4 GaN epitaxial structure of substrate

Technical Field

The utility model belongs to the semiconductor device field, concretely relates to based on ScAlMgO ₄ A GaN epitaxial structure of a substrate.

Background

The research and application of GaN material is the leading edge and hot spot of the current global semiconductor research, is a novel semiconductor material for developing microelectronic devices and optoelectronic devices, has the properties of wide direct band gap, strong atomic bond, high thermal conductivity, good chemical stability (hardly corroded by any acid) and the like, has strong anti-irradiation capability, and has wide prospect in the application aspects of optoelectronic devices, high-temperature high-power devices and high-frequency microwave devices. For a long time, the lattice mismatch between the GaN material and substrate materials such as Si, sapphire and the like is not well solved, so that the non-radiative defect density of the GaN epitaxial wafer is quite high.

Scandium aluminate magnesite (ScAlMgO) as compared to other conventional substrate materials ₄ ) The lattice mismatch rate with gallium nitride is about 1.8%, the thermal expansion coefficient mismatch is lower than that of other traditional substrate materials, and the substrate is an ideal gallium nitride epitaxial growth substrate, but the reports of epitaxial growth of gallium nitride films by taking scandium aluminate magnesite as the substrate are relatively less. For example, patent document CN106158592A discloses a method for preparing a GaN thin film grown on a magnesium-scandium aluminate substrate, which sequentially grows a GaN buffer layer, a GaN nucleation layer, a GaN amorphous layer and a GaN thin film on the magnesium-scandium aluminate substrate to obtain a high-quality GaN thin film. Also, for example, patent document CN113035689A discloses a method for producing a gallium nitride single crystal substrate, in which a GaN buffer layer is grown at a low temperature on a ScAlMgO4 substrate by an MOCVD method, a GaN single crystal layer is grown at a high temperature on the GaN buffer layer grown as a second stage by an HVPE method, and a high-quality GaN crystal substrate free from dislocation and crystal defects is realized by slicing, lapping, polishing, and cleaning. However, the quality of the GaN film grown on the ScAlMgO4 substrate by adopting the prior art is not ideal, and the half-peak width of GaN XRD (002) and (102) is as high as more than 300 arcsec.

SUMMERY OF THE UTILITY MODEL

In order to overcome the above problems in the prior art, the present invention provides a ScAlMgO-based optical fiber ₄ A GaN epitaxial structure of a substrate.

In order to achieve the above object, the utility model adopts the following technical scheme:

based on ScAlMgO ₄ GaN epitaxial structure of substrate comprising ScAlMgO stacked in sequence ₄ The substrate, the buffer layer, the island growth layer of GaN 3D, the stratiform growth layer of GaN 2D and HT-GaN growth layer.

Preferably, the ScAlMgO ₄ The substrate has an epitaxial surface with a (001) plane 0 to 0.3 degrees off the (110) plane.

Preferably, the buffer layer is an AlN, InAlGaN, GaN or AlGaN buffer layer.

More preferably, the buffer layer has a thickness of 1nm to 100 nm.

Preferably, the thickness of the GaN 3D island-shaped growth layer is 200nm to 1200 nm.

Preferably, the thickness of the GaN 2D layered growth layer is 1000 nm-3000 nm. Beyond 3000nm, the epitaxial structure warps, and below 1000nm, the defect density of the epitaxial structure is significantly increased.

More preferably, the GaN in the GaN 2D layered growth layer is doped or undoped GaN, and the doping concentration is 1E15cm ^-3 ～3E19cm ^-3 。

Preferably, the thickness of the HT-GaN growth layer is 1000 nm-5000 nm.

More preferably, the GaN in the HT-GaN growth layer is doped or undoped GaN with the doping concentration of 1E15cm ^-3 ～3E19cm ^-3 。

The preparation method of the GaN epitaxial structure comprises the following steps:

(1) in ScAlMgO ₄ Epitaxially growing a buffer layer on the surface of the substrate;

(2) epitaxially growing GaN on the buffer layer to form a GaN 3D island-shaped growth layer;

(3) epitaxially growing GaN on the GaN 3D island-shaped growth layer to form a GaN 2D layered growth layer;

(4) and growing GaN on the GaN 2D layered growth layer at a high temperature to form an HT-GaN growth layer.

Preferably, the growth rate of the buffer layer is 0.1-1 μm/h.

Preferably, the growth rate of the GaN 3D island-shaped growth layer is 0.5-1.5 μm/h.

Preferably, the growth rate of the GaN 2D layered growth layer is 1-6 mu m/h.

Preferably, the growth rate of the HT-GaN growth layer is 1-6 mu m/h.

Advantageous effects

Compared with the prior art, the utility model discloses can obviously reduce the defect density of GaN film, the half peak width of XRD (002) and (102) of gallium nitride can be less than below 200arcsec, and the simple easy operation of manufacturing process.

Drawings

FIG. 1 shows that the present invention is based on ScAlMgO ₄ Schematic view of a GaN epitaxial structure of a substrate.

FIG. 2 shows that the present invention is based on ScAlMgO ₄ A flow chart of a preparation process of the GaN epitaxial structure of the substrate.

Detailed Description

The technical solution of the present invention will be further described in detail with reference to the accompanying drawings and examples.

As shown in FIG. 1, the GaN epitaxial structure of the invention includes ScAlMgO ₄ A (SAM) substrate P1, and a buffer layer P2, a GaN 3D island-like growth layer P3, a GaN 2D layer-like growth layer P4, and an HT-GaN growth layer P5 sequentially stacked on the SAM substrate.

The ScAlMgO ₄ The substrate has an epitaxial surface with a (001) plane offset from a (110) plane by 0-0.3 degrees.

The thickness of the buffer layer P2 is 1nm, 10nm, 20nm, 30nm, 40nm, 50nm, 60nm, 70nm, 80nm, 90nm or 100 nm.

The buffer layer is made of AlN, InAlGaN, GaN or AlGaN.

The GaN 3D island-shaped growth layer is a layer which is grown in an island-shaped growth mode and consists of a plurality of isolated small islands. The thickness is 200nm, 300nm, 400nm, 500nm, 600nm, 700nm, 800nm, 900nm, 1000nm, 1100nm or 1200 nm.

And filling and covering channels among islands of the 3D island-shaped growth layer when the GaN 2D layered growth layer grows, wherein the thickness of the GaN 2D layered growth layer is 1000nm, 1200nm, 1400nm, 1600nm, 1800nm, 2000nm, 2200nm, 2400nm, 2600nm, 2800nm or 3000 nm. The thickness is the portion of the 3D island growth layer after the trenches are filled.

The GaN in the GaN 2D layered growth layer is doped or undoped GaN, and when the GaN is doped, the doping concentration can be controlled to be 1E15cm ^-3 ～3E19cm ^-3 。

The thickness of the HT-GaN growth layer is 1000nm, 1500nm, 2000nm, 2500nm, 3000nm, 3500nm, 4000nm, 4500nm or 5000 nm.

The GaN in the HT-GaN growth layer is doped or undoped GaN, and when the GaN is doped GaN, the doping concentration can be controlled to be 1E15cm ^-3 ～3E19cm ^-3 。

3D three-dimensional.

Two dimensions in 2D.

1E15＝1×10 ¹⁵ 。

3E19＝3×10 ¹⁹ 。

The preparation method of the GaN epitaxial structure of the present invention can select MOCVD (metal organic chemical vapor deposition) method, CVD (chemical vapor deposition) method, PECVD (plasma enhanced chemical vapor deposition) method, MBE (molecular beam epitaxy) method, etc.

In this embodiment, a process flow for preparing a GaN epitaxial structure on the (001) plane of the SAM by using an MOCVD method is shown in fig. 2, and the specific process is as follows:

(1) growing a first epitaxial layer on the SAM substrate: the AlN buffer layer grows at the temperature of 500-900 ℃ and the required gas flow N ₂ 10 to 80L/min, H ₂ Flow rate of 0 to 160L/min, NH ₃ 1-60L/min, aluminum source (trimethyl aluminum, TMAl) flow rate of 10-200 sccm/min, and growth rate of 0.1-1 μm/h.

(2) Growing a second epitaxial layer on the AlN buffer layer: undoped GaN 3D island growth layers. The specific conditions are as follows: growing in an island-like growth mode at a temperature of 1000-1080 deg.C and a required gas flow rate of N ₂ 10 to 80L/min, H ₂ Flow rate of 0 to 160L/min, NH ₃ 10-60L/min, gallium source (trimethyl gallium, TMGa) source flow of 100-500 sccm/min, and growth rate of 0.5-1.5 μm/h.

(3) A third epitaxial layer on the GaN 3D island-shaped growth layer: undoped GaN 2D layered growth layers. The concrete conditions are as follows: the growth temperature is 1000-1100 ℃, and the required gas flow is N ₂ 10 to 80L/min, H ₂ Flow rate of 0 to 160L/min, NH ₃ 10-70L/min, gallium source (trimethyl gallium) flow rate of 200-800 sccm/min, and growth rate of 1-6 μm/h.

(4) Growing a fourth epitaxial layer on the GaN 2D layered growth layer: the growth temperature of the HTGaN layer (i.e. the high-temperature gallium nitride layer) is in the range of 1020-1120 ℃, and the required gas flow N is ₂ 10 to 80L/min, H ₂ Flow rate of 0 to 160L/min, NH ₃ 10-70L/min, gallium source (trimethyl gallium) flow rate of 200-800 sccm/min, and growth rate of 1-6 μm/h.

Finally, it should be noted that: although the present invention has been described in detail with reference to the foregoing embodiments, it will be apparent to those skilled in the art that modifications may be made to the embodiments described in the foregoing embodiments, or equivalents may be substituted for elements thereof. Any modification, equivalent replacement, or improvement made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims (9)

1. Based on ScAlMgO ₄ A GaN epitaxial structure of a substrate, characterized by: comprises ScAlMgO which is laminated in sequence ₄ The substrate, the buffer layer, the island growth layer of GaN 3D, the stratiform growth layer of GaN 2D and HT-GaN growth layer.

2. The GaN epitaxial structure of claim 1 wherein: the ScAlMgO ₄ The substrate has an epitaxial surface with a (001) plane 0 to 0.3 degrees off the (110) plane.

3. The GaN epitaxial structure of claim 1 wherein: the buffer layer is an AlN, InAlGaN, GaN or AlGaN buffer layer.

4. The GaN epitaxial structure of claim 1 or 3 wherein: the thickness of the buffer layer is 1 nm-100 nm.

5. The GaN epitaxial structure of claim 1 wherein: the thickness of the GaN 3D island-shaped growth layer is 200 nm-1200 nm.

6. The GaN epitaxial structure of claim 1 wherein: the thickness of the GaN 2D layered growth layer is 1000 nm-3000 nm.

7. The GaN epitaxial structure of claim 6, wherein: the GaN is doped or undoped GaN, and the doping concentration is 1E15cm ^-3 ～3E19cm ^-3 。

8. The GaN epitaxial structure of claim 1 wherein: the thickness of the HT-GaN growth layer is 1000 nm-5000 nm.

9. The GaN epitaxial structure of claim 8 wherein: the GaN is doped or undoped GaN, and the doping concentration is 1E15cm ^-3 ～3E19cm ^-3 。

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