KR101936171B1 - Method for fabrication silicon carbide epi wafer and silicon carbide epi wafer - Google Patents

Abstract

A method for manufacturing a silicon carbide epitaxial wafer according to an embodiment includes: preparing a wafer in a susceptor; Injecting an etching gas into the susceptor; injecting a carbon source into the susceptor; Introducing a reaction gas into the susceptor to produce an intermediate compound; And reacting the intermediate compound with the wafer to form a silicon carbide epilayer on the wafer.
A silicon carbide epitaxial wafer according to an embodiment includes: a wafer; And a silicon carbide epi layer formed on the wafer, wherein the surface roughness of the silicon carbide epi layer is 0.1 nm to 1 nm or less.

Description

METHOD FOR FABRICATION SILICON CARBIDE EPI WAFER AND SILICON CARBIDE EPI WAFER Technical Field [1] The present invention relates to a silicon carbide epitaxial wafer,

The present disclosure relates to a silicon carbide epitaxial wafer manufacturing method and a silicon carbide epitaxial wafer.

In general, chemical vapor deposition (CVD) is widely used as a technique for forming various thin films on a substrate or a wafer. The chemical vapor deposition method is a deposition technique involving a chemical reaction, which uses a chemical reaction of a source material to form a semiconductor thin film, an insulating film, and the like on the wafer surface.

Such a chemical vapor deposition method and a vapor deposition apparatus have recently attracted attention as a very important technology among thin film forming techniques due to miniaturization of semiconductor devices and development of high efficiency and high output LED. And is currently being used for depositing various thin films on a wafer such as a silicon film, an oxide film, a silicon nitride film or a silicon oxynitride film, a tungsten film, and the like.

For example, in order to deposit a silicon carbide thin film on a substrate or a wafer, a reactive gas capable of reacting with the wafer must be introduced. Conventionally, silane (SiH ₄ ) or ethylene (C ₂ H ₄ ), which is a standard precursor, or methyltrichlorosilane (MTS) is added as a raw material and the raw material is heated to produce CH ₃ , SiCl _x, etc., the intermediate compound is introduced into the deposition section and reacted with the wafer positioned in the susceptor to deposit the silicon carbide epilayer.

However, on the surface of the wafer on which the silicon carbide epitaxial layer is deposited, silicon and silicon are not uniformly distributed, but the distribution of silicon is very high. At this time, since such silicon increases the surface roughness on the surface of the wafer, there is a problem that defects can be caused in the epitaxial wafer.

Accordingly, there is a need for a method capable of changing the surface of the silicon carbide wafer.

The embodiment is a silicon carbide epitaxial wafer manufacturing method for producing a silicon carbide epitaxial wafer having a surface roughness of 0.1 nm to 1 nm by modifying the surface of the wafer to a C-rich surface when silicon carbide is deposited on the wafer And silicon carbide epitaxial wafers.

A method for manufacturing a silicon carbide epitaxial wafer according to an embodiment includes: preparing a wafer in a susceptor; Injecting an etching gas into the susceptor; injecting a carbon source into the susceptor; Introducing a reaction gas into the susceptor to produce an intermediate compound; And reacting the intermediate compound with the wafer to form a silicon carbide epilayer on the wafer.

A silicon carbide epitaxial wafer according to an embodiment includes: a wafer; And a silicon carbide epi layer formed on the wafer, wherein the silicon carbide epi layer has a surface roughness of 0.1 nm to 1 nm.

The method for depositing silicon carbide according to an embodiment includes depositing an etching gas containing hydrogen chloride and a carbon source to deposit the surface of the silicon carbide wafer on a carbon-rich carbon-rich wafer -rich state.

Thus, the surface roughness and defects of the silicon carbide wafer can be reduced. That is, the surface roughness of the silicon carbide epi wafer on which the silicon carbide epilayer is deposited on the silicon carbide wafer according to the embodiment can be reduced to 0.1 nm to 1 nm, and the silicon carbide epi wafer with high quality, Can be produced.

1 is a process flow diagram of a silicon carbide deposition method according to an embodiment.
FIG. 2 is a view showing a step of injecting an etching gas onto a silicon carbide wafer. FIG.
Fig. 3 is a view showing a step of injecting a carbon source onto a silicon carbide wafer. Fig.
4 is a view showing the surface state of the silicon carbide wafer into which the carbon source is injected.
5 is a view showing a process of depositing an epi layer by injecting a reaction gas onto the silicon carbide wafer.
6 is a view showing a silicon carbide epitaxial wafer according to an embodiment.
FIG. 7 is an exploded perspective view of the deposition apparatus according to the embodiment. FIG.
8 is a perspective view showing a deposition apparatus according to an embodiment.
Fig. 9 is a part of a cross-sectional view cut along the line I-I 'in Fig.

In the description of the embodiments, it is to be understood that each layer (film), area, pattern or structure may be referred to as being "on" or "under / under" Quot; includes all that is formed directly or through another layer. The criteria for top / bottom or bottom / bottom of each layer are described with reference to the drawings.

The thickness or the size of each layer (film), region, pattern or structure in the drawings may be modified for clarity and convenience of explanation, and thus does not entirely reflect the actual size.

Hereinafter, a method for manufacturing a silicon carbide epitaxial wafer and a silicon carbide epitaxial wafer according to an embodiment will be described with reference to FIGS. 1 to 9. FIG.

FIG. 1 is a view showing a process flow diagram of a silicon carbide deposition method according to an embodiment. FIG. 2 is a view showing a step of injecting an etching gas onto a silicon carbide wafer. FIG. FIG. 4 is a view showing the surface state of the silicon carbide wafer into which the carbon source is injected, and FIG. 5 is a view showing a process of depositing an epitaxial layer by injecting a reaction gas onto the silicon carbide wafer. FIG. 6 is a view showing a silicon carbide epitaxial wafer according to an embodiment, and FIGS. 7 to 9 are views showing a deposition apparatus for depositing a silicon carbide epilayer on a wafer.

Referring to FIG. 1, a silicon carbide deposition method according to an embodiment includes: preparing a wafer (ST10); A step (ST20) of injecting an etching gas into the susceptor; Injecting a carbon source (C30) into the susceptor (ST30); Adding a reaction gas to the susceptor to produce an intermediate compound (ST40); And a step (ST50) of reacting the intermediate compound and the wafer to form a silicon carbide epilayer on the wafer.

In the step of preparing the wafer (ST10), the wafer can be placed in the susceptor. At this time, the wafer may be a silicon carbide wafer.

Subsequently, etching gas and a carbon source may be introduced into the susceptor in a step of injecting an etching gas into the susceptor (ST20) and a step of injecting a carbon source (C30) into the susceptor (ST30).

The etchant gas may include hydrogen chloride (HCl). The carbon source may also be an alkane (C _n H _{2n +2} , where 1? N? 3), an alkene (C _n H _2n where _{2? N} ? 3). ≪ / RTI > However, the embodiment is not limited thereto, and the carbon source may include a compound containing carbon, and the etching gas may include a compound containing chlorine.

The etching gas and the carbon source may be introduced after the susceptor is heated to a temperature of 1500 ° C to 1575 ° C. That is, the reaction gas may be introduced into the intermediate compound before it is ionized. In addition, the etching gas may be introduced before the carbon source. That is, the etching gas may be first introduced into the susceptor, and then the carbon source may be introduced. Further, the input amount of the etching gas and the input amount of the carbon source may be different. Preferably, the amount of the carbon source may be larger than the amount of the etching gas. For example, the input amount of the etching gas may be 120 ml / min, and the amount of the carbon source may be 270 ml / min.

The etching gas and the carbon source may be repeatedly introduced for 1 minute to 10 minutes. That is, the etching gas and the carbon source may be repeatedly supplied into the susceptor in order. Alternatively, after the etching gas is introduced, the carbon source can be injected repeatedly several times.

The etching gas may serve to etch the surface of the silicon carbide wafer. That is, referring to FIG. 2, the surface of the silicon carbide bulk wafer may be in a state where silicon (Si) is more abundant than carbon (C). However, such silicon may cause a surface of the silicon carbide wafer to be roughened by forming a certain protrusion on the surface of the wafer, thereby increasing the surface roughness. Such surface roughness can cause defects on the silicon carbide wafer, and thus, when the silicon carbide epilayer is deposited on the silicon carbide wafer, the defect is extended to affect the silicon carbide epilayer There is a problem.

Therefore, in the method of manufacturing a silicon carbide epitaxial wafer according to the embodiment, as shown in FIG. 3, the surface of the silicon carbide wafer is carbonized by injecting the etching gas and the carbon source onto the surface of a silicon carbide wafer rich in silicon Rich carbon-rich (C-rich) state. That is, when the susceptor is heated to a temperature of 1500 ° C to 1575 ° C, and then the etching gas and the carbon source are sequentially introduced, the wafer surface of the silicon carbide can be etched by the chlorine, The carbon contained in the silicon carbide wafer may form a carbon layer on the surface of the silicon carbide wafer. As a result, the protrusion by the silicon can be removed, and a silicon carbide wafer having a flat surface can be formed.

Next, a step (ST40) of injecting a reaction gas into the susceptor to generate an intermediate compound (ST40) and a step (ST50) in which the intermediate compound and the wafer react with each other to form a silicon carbide epilayer on the wafer Gas may be used to generate an intermediate compound that reacts with the wafer or the substrate in the susceptor and the intermediate compound may be introduced into the susceptor to react with the wafer to form a silicon carbide epilayer have. The raw material may include a liquid raw material or a vapor raw material. Preferably, the liquid raw material is trichlorosilane (methylchlorosilane, MTS) may include, the gaseous raw material is a silane (SiH ₄₎ and ethylene (C ₂ H ₄₎ or silane, and propane (C ₃ H ₈₎ of methyl . ≪ / RTI > However, the embodiment is not limited thereto, and the raw material may include various raw materials including carbon and silicon.

Hereinafter, the intermediate compound and the wafer react with each other to form a silicon carbide epilayer, with reference to FIGS. 7 to 9. FIG.

7 to 9, the deposition apparatus according to the embodiment includes a chamber 10, a susceptor 20, a source gas line 40, a wafer holder 30, and an induction coil 50.

The chamber 10 may have a cylindrical tube shape. Alternatively, the chamber 10 may have a rectangular box shape. The chamber 10 may receive the susceptor 20, the source gas line 40, and the wafer holder 30.

In addition, both ends of the chamber 10 are sealed, and the chamber 10 can prevent external inflow of gas and maintain a vacuum degree. The chamber 10 may include a quartz having high mechanical strength and excellent chemical durability. In addition, the chamber 10 has improved heat resistance.

Further, the chamber 10 may further include a heat insulating portion 60. The heat insulating portion 60 may function to preserve the heat in the chamber 10. Examples of the material used as the heat insulating portion include nitride ceramics, carbide ceramics, and graphite.

The susceptor 20 is disposed in the chamber 10. The susceptor 20 receives the source gas line 40 and the wafer holder 30. In addition, the susceptor 20 accommodates a substrate such as the wafer W or the like. Further, the reactive gas flows into the susceptor 20 through the source gas line 40.

As shown in Fig. 8, the susceptor 20 may include a susceptor upper plate 21, a susceptor lower plate 22, and susceptor side plates 23. Further, the susceptor upper plate 21 and the susceptor lower plate 22 are opposed to each other.

The susceptor 20 may be manufactured by positioning the susceptor upper plate 21 and the susceptor lower plate 22 and positioning the susceptor side plates 23 on both sides and then cementing them.

However, the embodiment is not limited to this, and a space for the gas passage can be produced in the rectangular parallelepiped susceptor 20.

The susceptor 20 may include graphite which has high heat resistance and is easy to process so that the susceptor 20 can withstand high temperature conditions. In addition, the susceptor 20 may have a structure in which silicon carbide is coated on the graphite body. Further, the susceptor 20 can be induction-heated itself.

The reactive gas supplied to the susceptor 20 is decomposed into an intermediate compound by heat, and in this state, it can be deposited on the wafer W or the like. For example, the reactant gas may be fed with methyltriclorosilane as a liquid raw material, silane as a vapor phase raw material, ethylene or silisilane and propane.

The raw material is decomposed into a radical containing silicon or carbon, and a silicon carbide epilayers can be grown on the wafer W. More specifically, the radical _{CH 3 ·, SiCl ·, SiCl} 2 ·, SiHCl ·, SiHCl 2 · such as CH _x · (1≤x <4) or _{SiCl x · (1≤ <x <} 4) one comprising the .

The source gas line 40 may have a rectangular tube shape. Examples of the material used as the source gas line 40 include quartz and the like.

The wafer holder 30 is disposed within the susceptor 20. More specifically, the wafer holder 30 can be disposed at the rear of the susceptor 20 with respect to the direction in which the source gas flows. The wafer holder 30 supports the wafer W. Examples of the material used for the wafer holder 30 include silicon carbide and graphite.

The induction coil 50 is disposed outside the chamber 10. More specifically, the induction coil 50 may surround the outer circumferential surface of the chamber 10. The induction coil 50 can induce and heat the susceptor 20 through electromagnetic induction. The induction coil 50 may wind the outer peripheral surface of the chamber 10.

The susceptor 20 can be heated by the induction coil 50 to a temperature of about 1500 ° C to about 1700 ° C. As described above, the etching gas and the carbon source may be injected to change the surface of the wafer to a carbon-rich state during a period in which the temperature rises to a temperature of 1500 ° C to 1575 ° C. Then, at a temperature of 1575 캜 to 1700 캜, the source gas is decomposed into an intermediate compound, and is introduced into the susceptor to be sprayed onto the wafer W. A silicon carbide epilayer is formed on the wafer W by the radicals injected onto the wafer W.

As described above, the silicon carbide epitaxial growth apparatus according to the embodiment forms a thin film such as the epitaxial layer on the substrate such as the wafer W, and the remaining gas is discharged to the discharge line To the outside.

Referring to FIG. 6, there is shown a silicon carbide epi wafer produced by the silicon carbide deposition method. The silicon carbide epitaxial wafer deposits the silicon carbide layer after changing the surface of the wafer to a carbon-rich state rich in carbon in a silicon-rich environment. Therefore, the silicon carbide epitaxial wafer has few defects, has a surface roughness of 0.1 nm to 1 nm, Silicon carbide epitaxial wafer can be produced. That is, the surface of the silicon carbide wafer is etched with an etching gas containing hydrogen chloride, and a carbon layer serving as a buffer layer is deposited between the silicon carbide wafer and the silicon carbide epi layer, followed by deposition of a silicon carbide epi- Therefore, it is possible to manufacture silicon carbide epitaxial wafers of high quality without surface defects in Chicago, reducing surface roughness.

The features, structures, effects and the like described in the foregoing embodiments are included in at least one embodiment of the present invention and are not necessarily limited to one embodiment. Further, the features, structures, effects, and the like illustrated in the embodiments may be combined or modified in other embodiments by those skilled in the art to which the embodiments belong. Therefore, it should be understood that the present invention is not limited to these combinations and modifications.

While the present invention has been particularly shown and described with reference to exemplary embodiments thereof, it is clearly understood that the same is by way of illustration and example only and is not to be construed as limiting the scope of the present invention. It can be seen that various modifications and applications are possible. For example, each component specifically shown in the embodiments may be modified and implemented. It is to be understood that the present invention may be embodied in many other specific forms without departing from the spirit or essential characteristics thereof.

Claims (14)

Preparing a silicon carbide wafer in the susceptor;
Injecting an etching gas into the susceptor;
Injecting a carbon source into the susceptor;
Introducing a reaction gas into the susceptor to produce an intermediate compound; And
Wherein the intermediate compound reacts with the silicon carbide wafer to form a silicon carbide epilayer on the silicon carbide wafer,
Wherein the carbon source is a carbon compound comprising an alkane (CnH2n + 2 wherein 1? N? 3), alkene (CnH2n where 2? N? 3) or alkyne (CnH2n-
Wherein the etching gas comprises hydrogen chloride (HCl)
The susceptor is heated to a temperature of 1500 캜 to 1700 캜,
The etching gas and the carbon source are introduced into the susceptor at a temperature of 1500 ° C to 1575 ° C,
The reaction gas is introduced into the susceptor at a temperature of 1575 캜 to 1700 캜,
The etching gas and the carbon source are repeatedly put in order,
The surface of the silicon carbide wafer before the etching gas and the carbon source are in a silicon-rich state,
A surface of the silicon carbide wafer is etched by the etching gas after the etching gas and the carbon source are introduced into the silicon carbide wafer, and a carbon layer is formed on the surface of the silicon carbide wafer by the carbon source, Wherein the silicon carbide epitaxial wafer is changed to a carbon-rich state. delete delete delete The method according to claim 1,
Wherein the input amount of the carbon source and the input amount of the etching gas are different. 6. The method of claim 5,
Wherein the amount of the carbon source is larger than the amount of the etching gas introduced into the silicon carbide epitaxial wafer. The method according to claim 1,
Wherein the reaction gas comprises carbon (C) and silicon (Si). The method according to claim 1,
Wherein the intermediate compound comprises CH _x (1? X <4) or SiCl _x (1? X <4). delete The method according to claim 1,
Wherein the carbon source and the etching gas are introduced for 1 to 10 minutes. delete delete The method according to claim 1,
Wherein the silicon carbide wafer has a surface roughness of 0.1 nm to 1 nm after the etching gas and the carbon source are introduced. delete

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