KR100729566B1 - Gallium nitride based single crystal substrate manufacturing method - Google Patents

Abstract

The present invention is nitrided as a final product in the same direction as the flat cutting (Flat Cutting) fabricated on the edge of the substrate for the surface orientation of the sapphire single crystal substrate is applied in the process of growing a gallium nitride-based single crystal thick film on the sapphire substrate The method for growing the surface orientation mark of a gallium-based single crystal substrate, and the cutting surface for the surface orientation mark of the sapphire substrate was prepared by predicting the surface orientation mark surface of the gallium nitride substrate in advance, the shape of the final substrate is sapphire After the separation of the substrate, the gallium nitride-based thick film is kept intact while maintaining the shape of the final substrate by adjusting only the diameter of the circular substrate, thereby minimizing the loss generated during the cutting of the circular substrate.

Description

Gallium nitride based single crystal substrate manufacturing method {Method for manufacturing a single crystal substrate of GaN}

1 is a diagram showing a lattice shape when a c-plane gallium nitride single crystal thick film is grown on a lattice of a c-plane sapphire single crystal substrate,

FIG. 2 illustrates a cutting surface for surface orientation marking of a general sapphire single crystal substrate and a surface orientation of a gallium nitride based single crystal thick film grown thereon, FIG. 2A is a plan view, and FIG. 2B is a sectional view,

3 is a sapphire single crystal modified from the existing (112-0) or its equivalent surface (11-00) or its equivalent surface based on the sapphire cutting surface for the surface orientation marker according to an embodiment of the present invention 3A is a plan view, FIG. 3B is a sectional view of the substrate and the gallium nitride based single crystal thick film grown thereon.

FIG. 4A is a view showing edge loss portions generated when a gallium nitride thick film is grown by using a sapphire substrate having a conventional cutting surface, when the final substrate is manufactured.

4B is a view showing a loss portion of an edge generated when the gallium nitride thick film is grown using a substrate having a modified cutting surface according to an exemplary embodiment of the present invention.

The present invention relates to a method for manufacturing a gallium nitride-based single crystal substrate, and more particularly, by using the same surface as the cutting surface for the surface orientation of the final substrate, the area utilization of the gallium nitride thick film to the final substrate after substrate separation The present invention relates to a method for producing a gallium nitride based single crystal substrate that can solve the reduction problem.

As is well known, the gallium nitride based single crystal substrate may be applied as a substrate of a blue violet laser diode and a blue / green light emitting diode device. Such gallium nitride-based single crystal substrates are generally grown on a sapphire, gallium arsenide (GaAs), silicon carbide (SiC) substrate more than a few hundredum thick film, and then removing the substrates by laser separation or etching, and separated gallium nitride Both sides of the single crystal thick film are processed to obtain a final gallium nitride based single crystal substrate.

In the conventional case, a part of the edge of the substrate is directed toward the plane 112-0 of the gallium nitride based single crystal for the surface orientation marking of a general gallium nitride based single crystal having c-plane (0001) or its equivalent as the main surface of the substrate. In the general case of forming a c-plane gallium nitride based single crystal substrate on a c-plane sapphire single crystal substrate, a hexagonal gallium nitride based single crystal lattice is a lattice when formed on a hexagonal sapphire single crystal lattice. For constant matching, it grows at an angle of 30 degrees on the c-plane. For example, the surface 112-0 of the gallium nitride single crystal is parallel to or at an angle of 60 degrees with the surface 11-00 of the sapphire single crystal, or conversely, the surface 11-00 of the gallium nitride single crystal is sapphire. It forms an angle of parallel or 60 degrees with the plane 112-0 of the single crystal. Therefore, the surface 112-0 of the gallium nitride based single crystal having the same surface index and the surface 112-0 of the sapphire single crystal form an angle of 30 degrees or 90 degrees to each other. Generally, the edge cutting surface indicating the surface orientation of a sapphire substrate sold is based on the surface 112-0 of the sapphire substrate single crystal. When the gallium nitride based single crystal is grown on the sapphire substrate, the edge cutting surface of the sapphire substrate As can be seen from FIG. 1 and FIG. 2, the gallium nitride-based single crystal coincides with the plane 11-00 or an equivalent plane thereof.

When the sapphire substrate is separated from the grown gallium nitride single crystal / sapphire laminate, the edge cutting for the surface orientation marking of the final product is performed when fabricating a free-standing substrate using the gallium nitride single crystal thick film. The board | substrate has been produced so that the surface may become the same as the surface 112-0 of sapphire substrate single crystal, or its equivalent surface.

As mentioned above, in the gallium nitride based single crystal / sapphire laminate, the cutting surface of the sapphire substrate coincides with the single crystal surface (11-00) or equivalent thereof of the gallium nitride based substrate, while the final gallium nitride based substrate is produced. Since the surface orientation marking cutting surface of the sapphire substrate single crystal surface (112-0), there is a problem that each difference of 30 degrees occurs. That is, when fabricating a wafer of 1 inch or more using a gallium nitride single crystal thick film in which a sapphire substrate is separated, it is (112-0) which forms 30 degrees with the (11-00) surface or its equivalent surface, which is the current surface orientation surface. There is a hassle to cut the surface orientation marker of the final substrate on the face or its equivalent. In this case, the biggest problem is that when fabricating a circular wafer, the substrate shape must be cut at 30 degrees as described above. As can be seen from FIG. 3, a part of the edge area of the gallium nitride single crystal thick film obtained immediately after substrate separation is cut. There is a problem that disappears.

Accordingly, the present invention has been made to solve the problem of reducing the area utilization of the gallium nitride thick film to the final substrate after the separation of the substrate, the purpose of which is a cutting surface for the surface orientation of the c-plane gallium nitride based substrate (112- 0) or a cutting surface for surface orientation marking of the c-plane sapphire substrate such that its equivalent surface is the same as the edge cutting surface of the gallium nitride thick film immediately after separation of the sapphire substrate from the existing (112-0) or its equivalent surface. It is to provide a method for producing a gallium nitride-based single crystal substrate to minimize the loss of gallium nitride thick film generated when cutting the circular shape (11-00) or its equivalent to form an angle of more than 1 inch.

The gallium nitride-based single crystal substrate manufacturing method according to an embodiment of the present invention for achieving the above object is a cutting surface for the surface orientation of the sapphire single crystal substrate and the cutting surface for the surface orientation of the gallium nitride substrate It is characterized in that it is formed to be the same two-dimensional.

According to the present invention, since the cutting surface for the surface orientation marking of the sapphire substrate was produced by predicting the surface orientation marking surface of the gallium nitride substrate in advance, the final substrate shape is the same as the separation form of the gallium nitride thick film after separation of the sapphire substrate. Since only the diameter of the circular substrate can be adjusted to maintain the shape of the final substrate in the maintained state, there is an effect of minimizing the loss generated when cutting the circular substrate.

Hereinafter, the present invention will be described in more detail.

In the sapphire single crystal substrate generally sold, the cutting surface for the surface orientation marking is (112-0) or equivalent to the sapphire single crystal, and the surface orientation marking surface is based on the sapphire substrate ( 11-00) or a gallium nitride-based single crystal thick film is grown using a sapphire single crystal substrate which is equivalent to the same. In the sapphire / gallium nitride laminate in which a gallium nitride thick film is grown on a sapphire substrate having a changed surface orientation cutting surface, the surface of the gallium nitride based thick film coinciding with the surface orientation cutting surface of the sapphire substrate becomes (112-0) or its equivalent. . When the sapphire substrate is separated from the laminate, the final substrate is formed in advance before the machining process. At this time, a cutting surface for surface orientation marking of the substrate is prepared. Unlike the case where the conventional sapphire is applied, in the present invention, since the cutting surface for the surface orientation marking of the sapphire substrate was prepared by predicting the surface orientation marking surface of the gallium nitride substrate in advance, the shape of the final substrate is the gallium nitride after separation of the sapphire substrate. The shape of the final substrate can be obtained by adjusting only the diameter of the circular substrate while maintaining the separation form of the thick film.

Hereinafter, the present invention will be described in more detail based on Examples and Comparative Examples. However, the following examples are only for illustrating the present invention, and the scope of the present invention is not limited thereto.

<Example>

In order to obtain a final 2 inch gallium nitride substrate, an experiment was performed using a 53 mm sapphire substrate slightly larger than 2 "in diameter. The cut surface for the surface orientation marking of the applied sapphire substrate is based on the existing (112-0) or The equivalent surface was changed to (11-00) or the equivalent surface.A gallium nitride thick film having a thickness of several hundred um was grown on the sapphire substrate, and the sapphire substrate was separated using a laser. When free-standing gallium nitride thick films are manufactured precisely to 2 "in diameter, they form a (112-0) or an azimuth cut face to its equivalent. Since the shape of the free-standing gallium nitride thick film obtained after the separation process is the same as that of the sapphire substrate, the cutting shape of the gallium nitride substrate is formed in the same place where the cutting shape of the sapphire substrate was present. At this time, the cutting surface of the free-standing gallium nitride thick film corresponds to (112-0) or its equivalent surface based on the gallium nitride substrate, so that the cutting crystal surface for the surface orientation marking of the final 2 "substrate completed after processing ( 112-0) or its equivalent. Therefore, while keeping the original gallium nitride thick film intact, only the rim is ground to within 1 mm to form an accurate 2 "diameter, and the final process proceeds to 2". A gallium nitride substrate was obtained.

Comparative Example

In order to obtain the final 2-inch gallium nitride substrate, experiments were performed using 55 mm sapphire substrates slightly larger than 2 "in diameter. The cut surface for the surface orientation marking of the applied sapphire substrate is based on the conventional (11-00) or The gallium nitride thick film having a thickness of several hundred um was grown on the sapphire substrate, and the sapphire substrate was separated using a laser.The free-standing gallium nitride thick film obtained after the separation process is shaped like the sapphire substrate. Since the cutting shape of the gallium nitride substrate is formed where the cutting shape of the sapphire substrate was the same, the cutting surface of the free-standing gallium nitride thick film is based on the gallium nitride substrate (11-00) or the like. As a mask, (112-0) or its equivalent is the cutting crystal plane for face orientation marking of the final 2 "substrate completed after processing A difference of 30 degrees from the plane will occur. Therefore, the cutting surface of the separated gallium nitride thick film is cut at an angle of 30 degrees to form a cutting surface for the surface orientation marking of the final gallium nitride substrate by cutting a portion of the substrate. After forming the cutting surface for the surface orientation mark through the cutting to form the correct diameter 2 "size through the edge portion grinding, the processing process was able to obtain a final 2" gallium nitride substrate.

As described above, according to the method for manufacturing a gallium nitride single crystal substrate according to the present invention, the present invention is a cutting surface of the free-standing gallium nitride-based single crystal thick film immediately after separation of the sapphire substrate of the final gallium nitride-based substrate As it is the same as the cutting surface for the surface orientation marking, by applying this it has the effect of reducing the area loss generated in the production of the circular substrate of gallium nitride-based thick film produced by applying the existing sapphire substrate.

 In addition, the cutting shape surface of the gallium nitride based thick film manufactured by using a conventional sapphire substrate to find the (112-0) plane or the equivalent surface of the gallium nitride based substrate, that is, the (11-00) surface based on the gallium nitride based substrate Or it has an effect that can solve the process hassle that needs to be cut again to find (112-0) or its equivalent surface forming 30 degrees in the equivalent plane.

Claims (6)

In the gallium nitride-based single crystal substrate manufacturing method, A gallium nitride based single crystal substrate manufacturing method for producing a gallium nitride based single crystal substrate by forming a cutting surface for the surface orientation marking on the sapphire single crystal substrate to be two-dimensionally identical to the cutting surface for the surface orientation marking of the gallium nitride substrate. The method of claim 1 If the cutting surface for the surface orientation marking of the sapphire single crystal substrate is (11-00) or the equivalent surface of the sapphire substrate, the cutting surface for the surface orientation marking of the gallium nitride substrate grown on the sapphire substrate is the sapphire A gallium nitride based single crystal substrate manufacturing method for forming (112-0) or an equivalent surface thereof based on a gallium nitride based single crystal substrate at the same position as the cutting surface for surface orientation marking of the single crystal substrate. The method of claim 1 If the cutting surface for the surface orientation mark of the sapphire single crystal substrate is (112-0) or its equivalent surface based on the sapphire substrate, the sapphire cutting surface for the surface orientation mark of the gallium nitride substrate grown on the sapphire substrate A gallium nitride based single crystal substrate manufacturing method for forming (11-00) or an equivalent surface thereof based on a gallium nitride based single crystal substrate at the same position as the cutting surface for the surface orientation marking of the single crystal substrate. An electronic device manufactured using a gallium nitride-based single crystal substrate manufactured by forming a cutting surface for the surface orientation mark on a sapphire single crystal substrate to be two-dimensionally the same as the cutting surface for the surface orientation mark of the gallium nitride substrate. The method of claim 4 If the cutting surface for the surface orientation marking of the sapphire single crystal substrate is (11-00) or the equivalent surface of the sapphire substrate, the cutting surface for the surface orientation marking of the gallium nitride substrate grown on the sapphire substrate is the sapphire An electronic device manufactured by using a gallium nitride based single crystal which forms (112-0) or an equivalent surface thereof based on a gallium nitride based single crystal substrate at the same position as the cutting surface for the surface orientation marking of the single crystal substrate. The method of claim 4, wherein If the cutting surface for the surface orientation mark of the sapphire single crystal substrate is (112-0) or its equivalent surface based on the sapphire substrate, the sapphire cutting surface for the surface orientation mark of the gallium nitride substrate grown on the sapphire substrate An electronic device manufactured by using a gallium nitride based single crystal substrate which forms (11-00) or an equivalent surface thereof based on a gallium nitride based single crystal substrate at the same position as the cutting surface for surface orientation marking of the single crystal substrate.

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