A semiconductor device and a method of fabricating the same

Abstract

The application provides a semiconductor device and a preparation method thereof. The preparation method comprises the following steps: arranging a medium layer on a substrate layer; forming a plurality of grooves in the medium layer; arranging a nucleation layer in the grooves, and the nucleation layer and the medium layer form a composite layer; growing a diamond layer on the composite layer; removing the substrate layer to expose the composite layer; and arranging a III-V compound layer on the surface of the composite layer. The composite layer formed by the medium layer and the nucleation layer arranged on the diamond layer in intervals is used as the nucleation layer for the growth of the III-V compound layer, and the dislocation is annihilated when the nucleation layer is laterally epitaxied, so that the density of dislocation generated by vertical epitaxy is reduced, thereby forming a high-quality III-V compound layer with low defect density and a HEMT device formed by the III-V compound layer.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of semiconductor integrated circuit manufacturing, and particularly relates to a semiconductor device and a preparation method thereof. BACKGROUND

[0002] Diamond material is very suitable for high-performance radio frequency device application due to its good thermal conductivity and insulation performance. However, since the price of diamond single crystal substrate is very high, polycrystalline diamond film is commonly used to form on a dielectric layer by chemical vapor deposition at present.

[0003] In the prior art, there are generally two methods for growing a gallium nitride device on diamond: one is to grow a nucleation layer on diamond, and then grow a gallium nitride epitaxial layer based on the nucleation layer; the other is to form a gallium nitride, a nucleation layer and diamond on a substrate, then flip the device, and remove the substrate to obtain a gallium nitride device with diamond as the substrate.

[0004] However, since there is a lattice mismatch and a thermal expansion coefficient mismatch between diamond and gallium nitride material, growing a gallium nitride device on diamond or growing diamond on gallium nitride often has a high defect density, thereby forming an epitaxial film with poor quality, which leads to the inability to prepare a gallium nitride device with good performance and reliability, and therefore how to form a high-quality gallium nitride thin film on a diamond substrate has become a key technology that needs to be broken through to realize a diamond-based gallium nitride device.

[0005] It should be noted that the above introduction to the technical background is only for the convenience of clearly and completely describing the technical scheme of the present application, and for the convenience of understanding by those skilled in the art, and the above technical scheme cannot be considered as known to those skilled in the art only because it is described in the background section of the present application. SUMMARY

[0006] In view of the above shortcomings of the prior art, the purpose of the present application is to provide a semiconductor device and a preparation method thereof, which are used to solve the problem of a large defect density of an epitaxial film grown in a diamond-based gallium nitride device in the prior art.

[0007] To achieve the above purpose, the present application provides a preparation method of a semiconductor device, which comprises:

[0008] providing a substrate layer;

[0009] providing a dielectric layer on the substrate layer;

[0010] forming a plurality of grooves in the dielectric layer;

[0011] providing a nucleation layer in the grooves, and the nucleation layer and the dielectric layer form a composite layer;

[0012] growing a diamond layer on the composite layer;

[0013] removing the substrate layer to expose a surface of the composite layer away from the diamond layer;

[0014] disposing a III-V compound layer on the surface of the composite layer away from the diamond layer.

[0015] Optionally, the material of the medium layer is silicon oxide, silicon nitride, or a combination thereof.

[0016] Optionally, the medium layer is disposed on the substrate layer by a plasma enhanced chemical vapor deposition method.

[0017] Optionally, the material of the nucleation layer is aluminum nitride.

[0018] Optionally, the nucleation layer is disposed in the recess by a metal organic chemical vapor deposition method; or / and the III-V compound layer is disposed on the surface of the composite layer away from the diamond layer by a metal organic chemical vapor deposition method.

[0019] Optionally, the method of removing the substrate layer comprises: flipping the semiconductor device; removing the substrate layer by etching or laser lift-off to expose the surface of the composite layer away from the diamond layer.

[0020] Optionally, the III-V compound layer comprises a composite structure of a barrier layer and a channel layer.

[0021] Optionally, the semiconductor device is a HEMT device.

[0022] Optionally, after disposing the III-V compound layer, an electrode layer is disposed on the III-V compound layer.

[0023] The present application also provides a semiconductor device obtained by any one of the above preparation methods, which comprises a diamond layer, a composite layer, a III-V compound layer, and an electrode layer; the composite layer is disposed on the diamond layer and comprises a nucleation layer and a medium layer; the III-V compound layer is disposed on the composite layer; and the electrode layer is disposed on the III-V compound layer.

[0024] As described above, the semiconductor device and the preparation method thereof have the following advantages:

[0025] The present application forms a composite layer of a medium layer and a nucleation layer by spacing them on a diamond layer, the composite layer serving as a nucleation layer for growth of a III-V compound layer, and the spaced nucleation layer is used to annihilate dislocations during lateral epitaxy, thereby reducing the dislocation density generated during vertical epitaxy, and forming a high-quality III-V compound layer with low defect density based on a diamond substrate and a HEMT device formed by the III-V compound layer. BRIEF DESCRIPTION OF DRAWINGS

[0026] Figure 1 A structure diagram showing the structure of the substrate layer provided in step 1 of the first embodiment of the present application.

[0027] Figure 2 A structure diagram showing the structure of the medium layer provided in step 2 of the first embodiment of the present application.

[0028] Figure 3 A structure diagram showing the structure of the recess formed in step 3 of the first embodiment of the present application.

[0029] Figure 4 A structure diagram showing the structure of the nucleation layer provided in step 4 of the first embodiment of the present application.

[0030] Figure 5 A structure diagram showing the structure of the diamond layer grown in step 5 of the first embodiment of the present application.

[0031] Figure 6 A structure diagram showing the structure of the substrate layer removed in step 6 of the first embodiment of the present application.

[0032] Figure 7 A structure diagram showing the structure of the III-V compound layer provided in step 7 of the first embodiment of the present application.

[0033] Figure 8 A structure diagram showing the structure of the electrode layer provided in step 7 of the first embodiment of the present application.

[0034] ELEMENT NUMBER EXPLANATION

[0035] 1, substrate layer; 2, medium layer; 3, recess; 4, nucleation layer; 5, diamond layer; 6, III-V compound layer; 7, gate electrode;

[0036] 8, drain electrode; 9, source electrode. DETAILED DESCRIPTION

[0037] The following specific examples illustrate the implementation of the present invention. Those skilled in the art can easily understand other advantages and effects of the present invention from the content disclosed in this specification. The present invention can also be implemented or applied through other different specific embodiments, and various details in this specification can also be modified or changed based on different viewpoints and applications without departing from the spirit of the present invention.

[0038] In the detailed description of embodiments of the present invention, for ease of explanation, the schematic diagrams illustrating the device structure may be partially enlarged without adhering to the general scale, and the schematic diagrams are merely examples and should not limit the scope of protection of the present invention. Furthermore, in actual manufacturing, the three-dimensional spatial dimensions of length, width, and depth should be included.

[0039] For ease of description, spatial relation terms such as “below,” “under,” “lower than,” “below,” “above,” and “upper” may be used herein to describe the relationship between one element or feature shown in the accompanying drawings and other elements or features. It will be understood that these spatial relation terms are intended to include directions other than those depicted in the accompanying drawings for devices in use or operation.

[0040] In the context of this application, the structure described above the first feature may include embodiments in which the first and second features are in direct contact, or embodiments in which additional features are formed between the first and second features, such that the first and second features may not be in direct contact.

[0041] It should be noted that the illustrations provided in this embodiment are only schematic representations of the basic concept of the present invention. Therefore, the illustrations only show the components related to the present invention and are not drawn according to the actual number, shape and size of the components in the actual implementation. In the actual implementation, the form, quantity and proportion of each component can be arbitrarily changed, and the layout of the components may also be more complex.

[0042] The vertical and horizontal directions mentioned in this application refer to the planar directions in the accompanying drawings. The direction parallel to the substrate is the horizontal direction, and the direction perpendicular to the substrate is the vertical direction.

[0043] Example 1:

[0044] like Figures 1-7 As shown, the present invention provides a method for fabricating a semiconductor device, the method comprising:

[0045] Step 1: Provide substrate layer 1;

[0046] Step 2: Deposit a dielectric layer 2 on the substrate layer 1;

[0047] Step 3: Form a plurality of grooves 3 in the dielectric layer 2;

[0048] Step 4: disposing a nucleation layer 4 in the grooves 3, the nucleation layer 4 and the medium layer 2 form a composite layer;

[0049] Step 5: growing a diamond layer 5 on the composite layer;

[0050] Step 6: removing the substrate layer 1 to expose the surface of the composite layer away from the diamond layer 5;

[0051] Step 7: disposing a III-V compound layer 6 on the surface of the composite layer away from the diamond layer 5.

[0052] The preparation method of the semiconductor device of the present application will be described in detail below with reference to the accompanying drawings, and it should be noted that the above sequence does not strictly represent the sequence of the preparation method of the semiconductor device protected by the present application, and those skilled in the art can change it according to the actual preparation steps.

[0053] First, as shown in FIG. 1, step 1 is performed to provide a substrate layer 1. Figure 1

[0054] Then, as shown in FIG. 2, step 2 is performed to dispose a medium layer 2 on the substrate layer 1. Figure 2

[0055] As an example, the material of the medium layer 2 is silicon oxide, silicon nitride or a combination of the two. Specifically, the medium layer 2 can also be other suitable medium layer materials that can be used to grow the diamond layer 5, which is not limited here.

[0056] In one embodiment, when the material of the substrate layer 1 is silicon, the material of the nucleation layer 4 is preferably aluminum nitride to achieve good growth of the nucleation layer 4; when the material of the substrate layer 1 is sapphire or other materials, the material of the nucleation layer 4 can be selected from other suitable nucleation transition materials to meet the conditions for growing the III-V compound layer 6 while being suitable for growth on the corresponding substrate layer 1 material.

[0057] As an example, the medium layer 2 is disposed on the substrate layer 1 by plasma enhanced chemical vapor deposition.

[0058] Next, as shown in FIG. 3, step 3 is performed to form a plurality of grooves 3 in the medium layer 2. Figure 3

[0059] In one embodiment, the grooves 3 are obtained by disposing a resist layer, exposing the resist layer to a mask plate, developing the resist layer, and then etching the medium layer 2 exposed after development to obtain a patterned medium layer 2 and the grooves 3 in the medium layer 2.

[0060] ​​​In one embodiment, the groove 3 is obtained by dry etching of the dielectric layer 2, such as isotropic plasma etching, reactive ion etching, sputtering etching, ion milling, ion beam assisted etching, or reactive ion beam etching.

[0061] Then, as Figure 4 As shown, in step 4, a nucleation layer 4 is formed in the groove 3, and the nucleation layer 4 and the dielectric layer 2 form a composite layer.

[0062] As an example, the material of the nucleation layer 4 is aluminum nitride.

[0063] As an example, the nucleation layer 4 is formed in the groove 3 by metal-organic chemical vapor deposition.

[0064] Next, as Figure 5 As shown, step 5 is performed to grow a diamond layer 5 on the composite layer.

[0065] Specifically, the dielectric layer 2 and the nucleation layer 4 in the composite layer both serve as the substrate for the growth of the diamond layer 5.

[0066] Then, as Figure 6 As shown, step 6 is performed to remove the substrate layer 1 to expose the surface of the composite layer away from the diamond layer 5.

[0067] As an example, a method for removing the substrate layer 1 includes: flipping the semiconductor device; removing the substrate layer 1 using etching or laser stripping methods to expose the surface of the composite layer away from the diamond layer 5.

[0068] Finally, as Figure 7 As shown, in step 7, a group III-V compound layer 6 is deposited on the surface of the composite layer away from the diamond layer 5.

[0069] The present application forms the composite layer by spacing the medium layer 2 and the nucleation layer 4, the composite layer serving as the growth layer of the group III-V compound layer 6, so that the spaced nucleation layers 4 merge into a layer when growing in the lateral direction to cross the medium layer 2, thereby annihilating the dislocations generated when the nucleation layer 4 grows in the vertical direction, thus greatly reducing the lattice defects generated during the growth of the nucleation layer 4 and improving the quality of the grown group III-V compound layer 6. Since the group III-V compound semiconductor structure with the diamond layer 5 as the substrate can greatly improve the heat conduction performance of the group III-V compound device and reduce the radio frequency loss, on this basis, the composite layer formed by the combination of the medium layer 2 and the nucleation layer 4 serves as the growth layer for growing the group III-V compound layer 6, reducing the dislocation density, thereby further improving the electrical and radio frequency performance of the group III-V compound device with diamond as the substrate, which is conducive to the practical production application and popularization of the group III-V compound device with diamond as the substrate in industry.

[0070] Specifically, the surface of the nucleation layer 4 close to the group III-V compound layer 6 and the surface of the medium layer 2 close to the group III-V compound layer 6 are flush.

[0071] In one embodiment, the thickness of the medium layer 2 is greater than the thickness of the nucleation layer 4, so that the lower surface of the medium layer 2 is lower than the lower surface of the nucleation layer 4 and is embedded in the diamond layer 5, so that the medium layer 2 has sufficient stability and firmness. Specifically, the thickness of the medium layer 2 and the nucleation layer 4 can also be adjusted as needed.

[0072] As an example, the group III-V compound layer 6 is disposed on the surface of the composite layer away from the diamond layer 5 by a metal organic chemical vapor deposition method.

[0073] Specifically, when using the metal organic chemical vapor deposition method, trimethylaluminum, ammonia and a carrier gas are introduced, and the carrier gas is hydrogen or nitrogen.

[0074] As an example, after the group III-V compound layer 6 is disposed, an electrode layer is disposed on the group III-V compound layer 6.

[0075] Specifically, as shown in Figure 8 The electrode layer includes a gate 7, a drain 8 and a source 9.

[0076] As an example, the group III-V compound layer 6 includes a composite structure of a barrier layer and a channel layer.

[0077] In one embodiment, one or more than one of InAlN, InAlGaN and AlGaN or any combination thereof is used as the material of the barrier layer of the semiconductor device, and other materials or combinations of materials can be used by the practitioner to obtain different III-V compound layers 6 as needed.

[0078] In one embodiment, the barrier layer is disposed on the channel layer, and GaN is used as the material of the channel layer, which has high resistance, is used to form a 2DEG (two-dimensional electron gas) together with the barrier layer, and reduces the background carrier concentration to reduce the drain 8 current collapse caused by the buffer layer trap effect.

[0079] In one embodiment, the III-V compound layer 6 further comprises a spacer layer (not shown in the figure), and the barrier layer is disposed on the spacer layer, and the spacer layer is an unintentionally doped AlN layer.

[0080] The present application separates the barrier layer and the channel layer by the spacer layer, thereby reducing the influence of electron scattering on the 2DEG mobility and concentration in the channel layer.

[0081] In another embodiment, a cap layer (not shown in the figure) is disposed on the barrier layer, and the material of the cap layer is GaN, which is used to reduce the current collapse of the drain 8, maintain the 2DEG generated by the polarization characteristics, reduce the gate 7 leakage current, enhance the ohmic contact and breakdown voltage between the source 9 and the drain 8.

[0082] As an example, the semiconductor device is a HEMT device.

[0083] Specifically, the HEMT device structure can be N-type or P-type, and the practitioner can select according to actual needs.

[0084] In one embodiment, the semiconductor device can also be other types of device structures, and the method of the present application is used to solve the problem of vertical defect density generated during growth.

[0085] Embodiment two:

[0086] The present application provides a semiconductor device, which is obtained by any one of the preparation methods described in the above embodiment one, and the semiconductor device comprises: a diamond layer 5, a composite layer, a III-V compound layer 6, and an electrode layer.

[0087] The composite layer is disposed on the diamond layer 5, and the composite layer is composed of a nucleation layer 4 and a dielectric layer 2 disposed in a spacer manner.

[0088] The III-V compound layer 6 is disposed on the composite layer, and the electrode layer is disposed on the III-V compound layer 6.

[0089] The present application forms the composite layer by spacing the nucleation layer 4 and the medium layer 2, and annihilates the dislocation formed by vertical growth in the nucleation layer 4 when the nucleation layer 4 grows laterally over the medium layer 2 to form a merged layer, so as to reduce the lattice defect density, thereby reducing the film quality of the III-V compound layer 6 grown on the nucleation layer 4, and improving the performance reliability of the semiconductor device formed on the diamond base.

[0090] For example, the material of the medium layer 2 is silicon oxide, silicon nitride, or a combination of the two.

[0091] For example, the material of the nucleation layer 4 is aluminum nitride.

[0092] Specifically, the surface of the nucleation layer 4 close to the III-V compound layer 6 and the surface of the medium layer 2 close to the III-V compound layer 6 are flush.

[0093] In one embodiment, the thickness of the medium layer 2 is greater than the thickness of the nucleation layer 4, so that the lower surface of the medium layer 2 is lower than the lower surface of the nucleation layer 4 and is embedded in the diamond layer 5, so that the medium layer 2 has sufficient stability and firmness. Specifically, the thickness of the medium layer 2 and the nucleation layer 4 can also be adjusted according to actual needs.

[0094] Specifically, the electrode layer includes a gate 7, a drain 8, and a source 9.

[0095] For example, the III-V compound layer 6 includes a composite structure of a barrier layer and a channel layer.

[0096] In one embodiment, one or more of InAlN, InAlGaN, and AlGaN or any combination thereof is used as the material of the barrier layer of the semiconductor device, and other materials or combinations of materials can be used by the practitioner to obtain different III-V compound layers 6 as needed.

[0097] In one embodiment, the barrier layer is disposed on the channel layer, and GaN is used as the material of the channel layer, which has high resistance, is used together with the barrier layer to form a 2DEG (two-dimensional electron gas), and reduces the background carrier concentration to reduce the drain 8 current collapse caused by the buffer layer trap effect.

[0098] In summary, the semiconductor device and the preparation method thereof can form a composite layer by spacing the medium layer and the nucleation layer on the diamond layer, the composite layer serves as the nucleation layer for the growth of the III-V compound layer, and the dislocation is annihilated when the spaced nucleation layer grows laterally, which reduces the dislocation density generated by vertical epitaxy, thereby forming a high-quality III-V compound layer with low defect density and a HEMT device composed of the diamond base.

[0099] Therefore, the present application effectively overcomes the shortcomings in the prior art and has high industrial utilization value.

[0100] The above embodiments only exemplarily illustrate the principles and effects of the present application, and are not used to limit the present application. Any person skilled in the art can modify or change the above embodiments without departing from the spirit and scope of the present application. Therefore, all equivalent modifications or changes completed by those skilled in the art without departing from the spirit and technical thought disclosed by the present application should be covered by the claims of the present application.

Claims

1. A method of manufacturing a semiconductor device, characterized by, The preparation method comprises: providing a substrate layer; providing a medium layer on the substrate layer; forming a plurality of grooves on the medium layer; providing a nucleation layer in the grooves, the nucleation layer and the medium layer being spaced apart to form a composite layer; growing a diamond layer on the composite layer; removing the substrate layer to expose a surface of the composite layer away from the diamond layer; providing a III-V compound layer on the surface of the composite layer away from the diamond layer, the spaced-apart nucleation layers merging into a layer when laterally growing to cross the medium layer, so that dislocations generated by the nucleation layers when growing in a vertical direction are annihilated, lattice defects generated during the growth of the nucleation layers are reduced, and the quality of the grown III-V compound layer is improved.

2. The method of producing a semiconductor device according to claim 1, wherein The material of the medium layer is silicon oxide, silicon nitride, or a combination of the two.

3. The method of producing a semiconductor device according to claim 1, wherein The medium layer is provided on the substrate layer by a plasma-enhanced chemical vapor deposition method.

4. The method of producing a semiconductor device according to claim 1, wherein The material of the nucleation layer is aluminum nitride.

5. The method of producing a semiconductor device according to claim 1, wherein The nucleation layer is provided in the grooves by a metal-organic chemical vapor deposition method; or / and the III-V compound layer is provided on the surface of the composite layer away from the diamond layer by a metal-organic chemical vapor deposition method.

6. The method of producing a semiconductor device according to claim 1, wherein The method for removing the substrate layer comprises: flipping the semiconductor device; and removing the substrate layer by etching or laser ablation to expose the surface of the composite layer away from the diamond layer.

7. The method of producing a semiconductor device according to Claim 1, wherein The III-V compound layer comprises a composite structure of a barrier layer and a channel layer.

8. The method of producing a semiconductor device according to Claim 1, wherein The semiconductor device is a HEMT device.

9. The method of producing a semiconductor device according to Claim 1, wherein The preparation method further comprises, after providing the III-V compound layer, providing an electrode layer on the III-V compound layer.

10. A semiconductor device, characterized by comprising: The semiconductor device is obtained by the preparation method of any one of claims 1-9, and comprises: a diamond layer, a composite layer, a III-V compound layer, and an electrode layer; the composite layer is located on the diamond layer, and is composed of a nucleation layer and a medium layer which are spaced apart. The III-V compound layer is provided on the composite layer, and the electrode layer is provided on the III-V compound layer.

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