CN106910675A - A composite substrate for preparing nitride electronic devices and its preparation method - Google Patents

Abstract

A composite substrate for preparing nitride electronic devices and a preparation method thereof, the composite substrate comprising a silicon substrate, an aluminum nitride layer and a patterned dielectric film, the aluminum nitride layer being prepared on the silicon substrate, the patterned dielectric film being prepared on the aluminum nitride layer, the patterned dielectric film having a plurality of patterns, and having interval gaps between adjacent patterned dielectric films, the patterned dielectric film being patterned in a circular, triangular, polygonal or striped shape, and the patterned dielectric film being made of silicon dioxide, silicon nitride, titanium nitride, a metal dielectric layer or polycrystalline aluminum oxide. The present invention solves the stress problem encountered in the heterogeneous growth of nitride electronic power devices, and is conducive to improving device performance.

Description

A composite substrate for preparing nitride electronic devices and its preparation method

technical field

The invention belongs to the technical field of semiconductor optoelectronic devices, in particular to a composite substrate for preparing nitride electronic devices and a preparation method thereof.

Background technique

The third-generation semiconductor devices based on Si, GaN, SiC and their corresponding compounds InGaN, AlN, and AlGaN have recently attracted much attention, and have achieved major theoretical breakthroughs, and some fields have achieved industrial applications. For example, silicon carbide power devices have completed pre-industrial research and achieved civilian applications in the small-scale power field. The high withstand voltage, high mobility and high saturation carrier concentration of nitride are the common characteristics of the third-generation semiconductors, which are expected to break through the limits of existing silicon devices for large-scale applications.

At present, GaN-based optoelectronic devices are generally prepared with Si, sapphire, and SiC substrates as heterogeneous epitaxial devices, lacking GaN substrates. Nitride heteroepitaxy based on large mismatch is widely used. Large mismatch heteroepitaxy has problems of large lattice mismatch and thermal stress mismatch, lattice mismatch will introduce higher dislocation density, and thermal stress will cause cracking problems. The existing epitaxial technology of gallium nitride optoelectronic devices is mainly to adjust the process parameters (temperature, time, flow, pressure, etc.) on the contrary. It is difficult to achieve the effects of crystal quality improvement and stress release at the same time. Stress and high dislocation density have become the main problems that plague the performance improvement of GaN devices. The stress problem is especially serious in nitride electronic devices with large silicon wafer substrates. Further improving the device performance of nitrides on the basis of existing technologies requires a technology that simultaneously takes stress relief and crystal quality into consideration.

Contents of the invention

The technical problem to be solved by the present invention is to provide a composite substrate for preparing nitride electronic devices and a preparation method thereof, which is beneficial to improving the performance of electronic devices.

In order to solve the above technical problems, the present invention takes the following technical solutions:

A composite substrate for preparing nitride electronic devices, the composite substrate includes a silicon substrate, an aluminum nitride layer and a patterned dielectric film, the aluminum nitride layer is prepared on the silicon substrate, and the patterned dielectric film is prepared On the aluminum nitride layer, there are several patterned dielectric films, and there are gaps between adjacent patterned dielectric films.

The patterning of the patterned dielectric film is circular, triangular, polygonal or striped.

The patterned dielectric film is made of silicon dioxide, silicon nitride, titanium nitride, metal dielectric layer or polycrystalline aluminum oxide.

The gap between the adjacent patterned dielectric films is 10nm-2um.

The aluminum nitride layer is at least one layer of quasi-single crystal or single crystal.

The thickness of the aluminum nitride layer is 20nm-2um.

The silicon substrate is N-type, P-type or intrinsic, with a size range of 2-16 inches and a thickness of 200um-2mm.

A method for preparing a composite substrate, comprising the steps of:

Choose N-type, P-type or intrinsic silicon substrate;

preparing an aluminum nitride layer on a silicon substrate;

preparing a layer of dielectric film on the aluminum nitride layer;

A layer of glue is prepared on the surface of the dielectric film by the method of throwing glue;

The dielectric film is patterned by nanoimprinting, and the adhesive layer is squeezed with a graphic template to form the same pattern as the graphic template on the adhesive layer. At this time, part of the dielectric film is directly exposed, and part of the dielectric film is covered by the adhesive layer. graphics masking;

Remove the directly exposed dielectric film by chemical etching or physical etching;

Then remove the adhesive layer pattern covering the dielectric film by chemical etching, and obtain a composite substrate with a patterned dielectric film/aluminum nitride layer/silicon substrate structure.

The aluminum nitride layer is prepared on the silicon substrate by MOCVD, PLD or sputtering or chemical methods.

The dielectric film is prepared by PECVD, PLD, PVD, sputtering, vapor deposition or chemical solution spin coating.

The composite substrate prepared by the invention has better uniformity and smaller pattern period size, which is conducive to improving the crystal quality of nitrides, and has a better effect on the stress release of nitride electronic devices heterogeneous epitaxy, and has a better effect on silicon-based nitrides. The performance of electronic devices has a good effect of improving.

Description of drawings

Accompanying drawing 1 is the schematic sectional view of composite substrate of the present invention;

Accompanying drawing 2 is the preparation process schematic diagram of the inventive method;

Accompanying drawing 3 is the schematic cross-sectional view of the electronic device prepared by the composite substrate of the present invention.

detailed description

In order to facilitate the understanding of those skilled in the art, the present invention will be further described below in conjunction with the accompanying drawings.

As shown in accompanying drawing 1, a kind of composite substrate for preparing nitride electronic device, described composite substrate comprises silicon substrate 1, aluminum nitride layer 2 and patterned dielectric film 3, and aluminum nitride layer 2 is prepared On the silicon substrate 1, a patterned dielectric film 3 is prepared on the aluminum nitride layer 2. There are several patterned dielectric films, and there are gaps 4 between adjacent patterned dielectric films, and the gap is 10 nm. -2um, the specific value can be flexibly selected within this range. An aluminum nitride layer can be prepared on a silicon substrate by physical or chemical methods such as MOCVD, PLD, and sputtering. The thickness of the aluminum nitride layer is 20nm-2um, preferably 80nm-500nm. The aluminum nitride layer can be a quasi-single crystal, a single layer or multiple layers of single crystal, that is, one layer, two layers, three layers or other quantities.

The patterning of the patterned dielectric film is circular, triangular, polygonal, or striped, or other shapes, and the above list is not limited. The patterned dielectric film is made of silicon dioxide, silicon nitride, titanium nitride, metal dielectric layer or polycrystalline aluminum oxide.

The silicon substrate is N-type, P-type or intrinsic, with a size range of 2-16 inches and a thickness of 200um-2mm.

By preparing a patterned dielectric film on the aluminum nitride layer/silicon substrate double-layer structure, it has a good effect on stress release.

In addition, as shown in accompanying drawing 2, the present invention also discloses a preparation method of a composite substrate, comprising the following steps:

S1, select N-type, P-type or intrinsic silicon substrate 1 . In this embodiment, a P-type silicon substrate with an 8-inch <111> crystal orientation is selected.

S2, preparing an aluminum nitride layer 2 on the silicon substrate 1. It can be prepared on a silicon substrate by MOCVD, PLD, sputtering or chemical methods. In this embodiment, a 100nm thick aluminum nitride layer is deposited by MOCVD method.

S3, preparing a layer of dielectric film 3 on the aluminum nitride layer 2. It can be prepared by PECVD, PLD, PVD, sputtering, vapor deposition or chemical solution spin coating. In this embodiment, PECVD is used to prepare a layer of dielectric film with a thickness of 50 nm.

S4, preparing a layer of 50nm glue layer 5 on the surface 3 of the dielectric film by using the glue-spinning method.

S5, the dielectric film 3 is patterned by nanoimprinting, the adhesive layer 5 is squeezed by the graphic template 7, and the same pattern 6 as the graphic template 7 is formed on the adhesive layer 5, the dielectric film/aluminum nitride layer/ The silicon substrate forms an array of adhesive layer patterns. At this time, part of the dielectric film is directly exposed, and part of the dielectric film is covered by the pattern on the adhesive layer to form an adhesive layer/dielectric film pattern 8 . The graphic of the graphic template is a circular display, the diameter of the circle is 20nm, and the distance between the circles is 10nm.

S6, removing the directly exposed dielectric film by chemical etching or physical etching. Put it into the ICP chamber for etching, the etching power is 3KW, the flow rate of the etching gas boron trichloride is 100 SCCM, and the directly exposed aluminum nitride layer is etched and removed, and the dielectric film covered by the pattern of the adhesive layer save.

S7, removing the adhesive layer pattern covering the dielectric film by chemical etching to obtain a composite substrate with a patterned dielectric film 9/aluminum nitride layer 2/silicon substrate 1 structure. Take out the etched sample from the ICP chamber, put it into the chemical etching solution BOE for degumming treatment, and remove the glue layer.

When using this composite substrate to prepare electronic devices, as shown in Figure 3, use MOCVD to perform GaN HEMT device 10 on the composite substrate composed of patterned dielectric film 3/aluminum nitride layer 2\silicon substrate 1 grow. Since the single crystal gallium nitride is only grown on the surface of the patterned aluminum nitride layer when growing in MOCVD, the original spacer region (without the aluminum nitride seed layer region) is finally covered by lateral epitaxy to form a unified single crystalline GaN, and only polycrystalline GaN or air gaps are formed in the region 4A, thereby reducing the contact area between the GaN HEMT device 10 and the silicon substrate 1, which is beneficial to stress release, thereby reducing HEMT cracking.

It should be noted that the above description is not a limitation of the present invention, and any obvious replacements are within the protection scope of the present invention without departing from the inventive concept of the present invention.

Claims (10)

1. a kind of compound substrate for preparing nitride electronic devices, it is characterised in that the compound substrate include silicon substrate, Aln layer and patterned media film, aln layer are prepared on a silicon substrate, and patterned media film preparation, should on aln layer Patterned media film has several, and has interval gap between adjacent patterned media film.

2. the compound substrate for preparing nitride electronic devices according to claim 1, it is characterised in that the figure That changes deielectric-coating is patterned into circle, triangle, polygon or striated.

3. the compound substrate for preparing nitride electronic devices according to claim 2, it is characterised in that the figure Change deielectric-coating to be made up of silica, silicon nitride, titanium nitride, metallic dielectric layer or polycrystal alumina.

4. the compound substrate for preparing nitride electronic devices according to claim 3, it is characterised in that described adjacent Interval gap between patterned media film is 10nm-2um.

5. the compound substrate for preparing nitride electronic devices according to claim 4, it is characterised in that the nitridation Aluminium lamination is at least one layer of quasi- monocrystalline or monocrystalline.

6. the compound substrate for preparing nitride electronic devices according to claim 5, it is characterised in that the nitridation The thickness of aluminium lamination is 20nm-2um.

7. the compound substrate for preparing nitride electronic devices according to claim 6, it is characterised in that the silicon lining Bottom is N-type, p-type or intrinsic, and size range is 2-16 inches, and thickness is 200um-2mm.

8. a kind of preparation method of compound substrate according to any one of claim 1-7, comprises the following steps：

Selection N-type, p-type or intrinsic silicon substrate；

One layer of aln layer is prepared on a silicon substrate；

A layer dielectric is prepared on aln layer；

Using the method for whirl coating one layer of glue-line is prepared on deielectric-coating surface；

Treatment is patterned to deielectric-coating by nano impression, glue-line is extruded using graphics template, the shape on glue-line Into with graphics template identical figure, now certain media film is directly exposed, certain media film by glue-line figure cover；

Directly exposed deielectric-coating is removed by the method for chemical attack or physical etchings；

The glue-line figure for being covered with deielectric-coating is removed by chemical corrosion method again, patterned media film/aln layer/silicon is obtained The compound substrate of substrat structure.

9. the preparation method of compound substrate according to claim 8, it is characterised in that the aln layer by MOCVD, PLD or sputtering or chemical mode are prepared on a silicon substrate.

10. the preparation method of compound substrate according to claim 9, it is characterised in that the deielectric-coating by PECVD, It is prepared by PLD, PVD, sputtering, evaporation or chemical solution spin coating mode.