KR20090043109A - Methode of manufacturing the thin layer of single-crystal gaas on silicon substrate by ion-cut and wafer bonding technique - Google Patents

Abstract

The present invention relates to a method for producing a single crystal GaAs thin film on a silicon wafer using ion implantation and wafer bonding technology. The object of the present invention is to provide a silicon wafer using ion-cut technology and wafer bonding technology. The present invention provides a method for fabricating a GaAs single crystal thin film with little bonded lattice defects. According to an aspect of the present invention, there is provided a method of forming a single crystal GaAs thin film on a silicon wafer, comprising: an ion implantation step of irradiating ions to the GaAs wafer for peeling the GaAs wafer; Forming a silicon oxide layer on the GaAs wafer to be used as a buffer layer with the silicon wafer before or after the ion implantation step, followed by cleaning the GaAs wafer and the silicon wafer, and then putting the GaAs wafer and the silicon wafer together A wafer bonding step comprising a step of applying pressure to the wafer; Heat-treating the bonded GaAs wafer and the silicon wafer to exfoliate the ion-irradiated GaAs wafer; and a method of manufacturing a single crystal GaAs thin film on a silicon wafer using an ion-cut technique and a wafer bonding technique by ion implantation, comprising: It is characterized by the technical idea.

Ion-cut, ion implantation, wafer bonding, GaAs thin film

Description

Method for manufacturing the thin layer of single-crystal GaAs on silicon substrate by ion-cut and wafer bonding technique using ion implantation technology and wafer bonding technology

The present invention relates to a method for producing a single crystal GaAs thin film on a silicon wafer using ion-cut technology by ion implantation and wafer bonding technology, and more specifically, by using ion-cut technology and wafer bonding technology by hydrogen or helium ion implantation. A method of fabricating a GaAs single crystal thin film with few lattice defects associated with a silicon wafer.

In the case of silicon, the semiconductor processing process is very developed, so it is economically effective and it is easy to manufacture a highly integrated circuit. GaAs has the advantage of excellent electrical and optical characteristics.

Therefore, there is a growing interest in a technique of bonding a GaAs layer to a silicon wafer and using it as a single wafer to combine these features.

In order to fabricate the above structure, the GaAs layer was previously fabricated by heteroepitaxial growth on a silicon wafer.

In the case of the specimen fabricated by the technique of heteroepitaxial growth of the GaAs layer on the silicon wafer as in the prior art, many defects are formed in the lattice due to 4.1% crystal structure mismatch and thermal mismatch due to the difference in coefficient of thermal expansion (10 ⁶ ~ 10 ⁷ / cm ² There has been a structural problem.

An object of the present invention for solving the above problems is a method of manufacturing a GaAs single crystal thin film having almost no lattice defects bonded to a silicon wafer using ion-cut technology and wafer bonding technology by ion (H or He) implantation. To provide.

The present invention to achieve the object as described above and to perform the problem for removing the conventional defects in the method of forming a single crystal GaAs thin film on a silicon wafer,

Forming a silicon oxide layer on the GaAs wafer to be used as a buffer layer with the silicon wafer,

An ion implantation step of irradiating ions to the GaAs wafer for peeling the GaAs wafer;

Thereafter cleaning the GaAs wafer and the silicon wafer, and then bonding the GaAs wafer and the silicon wafer to each other by bonding the GaAs wafer and the silicon wafer to each other by applying pressure to the center;

Heat-treating the bonded GaAs wafer and the silicon wafer to exfoliate the ion-irradiated GaAs wafer; and a method of manufacturing a single crystal GaAs thin film on a silicon wafer using an ion-cut technique and a wafer bonding technique by ion implantation, comprising: By providing.

In addition, the present invention is a method of forming a single crystal GaAs thin film on a silicon wafer,

An ion implantation step of irradiating ions to the GaAs wafer for peeling the GaAs wafer;

Then forming a silicon oxide layer on the GaAs wafer to be used as a buffer layer with the silicon wafer;

Thereafter cleaning the GaAs wafer and the silicon wafer, and then bonding the GaAs wafer and the silicon wafer to each other by bonding the GaAs wafer and the silicon wafer to each other by applying pressure to the center;

Heat-treating the bonded GaAs wafer and the silicon wafer to exfoliate the ion-irradiated GaAs wafer; a method of fabricating a single crystal GaAs thin film on a silicon wafer using ion-cut technology and wafer bonding technology comprising ion implantation Is achieved by providing

The ion implantation step is characterized in that the step of implanting hydrogen ions.

The ion implantation step is characterized in that the step of implanting helium ions.

Injecting ions from the hydrogen is characterized in that to irradiate the hydrogen ion under the conditions of irradiation temperature 120 ~ 160 ℃, irradiation amount 1 ~ 2 x 10 ¹⁷ H ⁺ / cm ² in order to cause the peeling of the GaAs wafer.

In the step of injecting helium ions is characterized in that to irradiate the helium ions under the conditions of irradiation temperature of room temperature (within 60 ℃), irradiation amount of 1.8 ~ 5 x 10 ¹⁶ He ⁺ / cm ² in order to cause peeling of GaAs wafer do.

Forming a silicon oxide layer on the GaAs wafer,

Before ion implantation into a GaAs wafer, a dozens of Si ₃ N ₄ layers are grown on the surface by PECVD at a high temperature of 300 ° C. or higher, and then a SiO ₂ layer having a desired thickness (hundreds of kPa) is grown, and CMP (Chemical Mechanical) SiO ₂ layer formation step using PECVD and CMP to give a surface roughness of less than 5 kW by a Polishing) process.

Forming a silicon oxide layer on the GaAs wafer,

After ion implanted GaAs wafer was cleaned and rinsed in 5% HCl solution for 3 minutes and dried at 150 ℃ for 5 minutes, spin coating was applied on GaAs wafer using Methylphenyl-silsesquioxane (700F, Filmtronics). After the heat treatment at 150 ℃ for 5 minutes to form a SiO ₂ layer using SOG to give a surface roughness of about 5 ;; characterized in that the.

The step of peeling the ion irradiated GaAs wafer is characterized in that the heat treatment to 200 ~ 300 ℃.

According to the present invention, the GaAs single crystal thin film can be manufactured in the GaAs single crystal thin film, which has almost no lattice defects associated with the silicon wafer, compared to the heteroepitaxial method, and the GaAs single crystal thin film combined with various other media. It is a useful invention with an invention that is expected to be greatly used in the industry.

Hereinafter, the configuration and the operation of the embodiments of the present invention will be described in detail with reference to the accompanying drawings.

1A is a process chart of manufacturing a single crystal GaAs thin film combined with a silicon wafer according to an embodiment of the present invention, Figure 1B is a process chart of manufacturing a single crystal GaAs thin film combined with a silicon wafer according to another embodiment of the present invention, Figure 2 In the hydrogen ion implantation according to the invention, it is a graph showing the peeling phenomenon according to the irradiation temperature and irradiation amount, Figure 3a is a FE-SEM photograph of the specimen prepared according to the process of one embodiment of the present invention, Figure 3b is another of the present invention FE-SEM photograph of the specimen prepared according to the process of the embodiment, Figure 4 is a 4 inch GaAs on SiO ₂ / Si wafer photograph produced by the process according to the invention, Figure 5 is a GaAs on Si ₂ produced by this process A cross-sectional TEM photograph of a / Si wafer.

The method for fabricating a GaAs single crystal thin film bonded to a silicon wafer according to the present invention consists of two techniques. GaAs thin film is separated by GaAs and silicon wafer by wafer bonding method and ion-cut method by ion implantation.

1A and 2B illustrate the two process methods described above. The GaAs wafer is irradiated with H or He ions, and then bonded to the silicon wafer using a silicon oxide layer. When the wafer thus bonded is heat treated, peeling occurs at the ion implanted position to obtain a single crystal GaAs layer of the thin film bonded to the silicon wafer.

The most important content in this process is the ion irradiation conditions causing peeling and the method of forming the silicon oxide layer for bonding the wafer. Hereinafter, each step will be described in detail.

1) Ion implantation step

When ions are implanted into GaAs and subjected to heat treatment, GaAs is peeled off at the location where ions are implanted. This technique is called ion-cut. . In the present invention, the optimum ion-cut conditions using two ions of hydrogen (H) and helium (He) ions were investigated and presented.

(a) Hydrogen ion irradiation step

Hydrogen ions of 80 keV were used to prepare a GaAs thin film having a thickness of about 500 nm, and ions were implanted by tilting the (100) GaAs wafer at 7 ^° . In order to determine the optimum irradiation temperature and irradiation amount at which peeling takes place, the irradiation dose was varied from 0.4 to 2.0 x 10 ¹⁷ H ⁺ / cm ² at an irradiation temperature range of 100 to 300 ° C. At this time, in order to measure the exact temperature of the GaAs wafer to be irradiated, the temperature was measured by directly contacting the thermocouple to the wafer surface where the ion irradiation occurs. When the sample is heat-treated at 200 to 300 ° C., blisters and flakes may occur. By observing this phenomenon, it is possible to derive an optimal condition in which the peeling phenomenon occurs after the heat treatment, although there is no change in the ion implantation state. Figure 2 shows the results of the experiment under such conditions. Also it has confirmed that the optimal hydrogen ion implantation conditions, the results of Figure 2, must be in order to take place the ion-cut is ^{1 ~ 2 x 10 17 H +} / cm 2 dose at a temperature between 120 ~ 160 ℃ irradiation.

(b) Helium ion irradiation step

To prepare a GaAs thin film having a thickness of about 500 nm, 100 keV helium ions were used, and ions were implanted by tilting the (100) GaAs wafer at 7 ^° . In the case of helium, the irradiation temperature is room temperature (20 ~ 60 ℃), the irradiation amount 1.8 ~ 5 x 10 ¹⁶ He ⁺ / cm ^{2 When} irradiated after heat treatment, peeling phenomenon occurs explosive.

2) Wafer Bonding Step

In order to bond the silicon wafer and the GaAs wafer, a direct wafer bonding method was used. In general, GaAs and silicon wafers are not directly bonded directly without pretreatment. Therefore, a silicon oxide layer is formed as a buffer layer between GaAs and the silicon wafer. For the silicon oxide layer, PECVD and spin-on-glass (SOG) methods were used.

(a) SiO ₂ layer formation step using Plasma Enhanced Chemical Vapor Deposion (PECVD) and Chemical Mechnical Polishing (CMP)

PECVD fabricates a SiO ₂ layer on the GaAs wafer. In order to perform the PECVD process, a high temperature treatment of about 350 ° C. is required, so it is performed before ion implantation. PECVD grows dozens of Å of Si ₃ N ₄ layers and then grows SiO ₂ layers of desired thickness (hundreds of Å). In the SiO ₂ layer thus prepared, the surface roughness exceeds 70 kPa, and since the direct bonding does not occur under such conditions, the surface roughness of 5 kPa was achieved by the CMP process.

(b) SiO ₂ layer formation step using spin-on-glass

In the case of the SOG process, since it can be processed at 150 ° C, the SOG process is performed after ion implantation.

The ion-implanted GaAs wafer is cleaned and rinsed in 5% HCl solution for 3 minutes and dried at 150 ° C. for 5 minutes to prepare for spin coating. Methylphenylsilsesquioxane (700F, Filmtronics) was used to spin coat the GaAs wafer, followed by heat treatment at 150 ° C for 5 minutes.

The SiO ₂ layer produced by the SOG process is suitable for direct bonding at a surface roughness of 5 kW. As described above, when the SiO ₂ layer is manufactured by using SOG, the process is simpler than when the SiO ₂ layer is produced by PECVD, and the process can be performed after ion implantation. It is a very efficient way to minimize it.

(c) wafer cleaning and bonding step

In order to bond the wafer, the surface contaminants must be removed. GaAs wafers were rinsed with 5% HCl solution for 3 minutes and then rinsed with tertiary distilled water, and silicon wafers were cleaned using SPM and SC1 cleaning processes. The cleaned wafers are bonded together without any other processing and pressurized in the center to form a bond.

3) GaAs peeling and CMP step by heat treatment

In order to peel the ion-irradiated GaAs wafer, heat treatment should be performed at 200 ~ 300 ℃. When the temperature is lower than 200 ° C., peeling does not occur, and when the temperature exceeds 300 ° C., the bonded wafer may be damaged due to the difference between the silicon and GaAs thermal expansion coefficients. This heat treatment causes peeling at the ion-irradiated position to obtain a single crystal GaAs thin film bonded to the silicon wafer (FIGS. 3A and 3B).

Since the surface roughness of GaAs formed by exfoliation is considerably large with 10-20 nm, the surface roughness should be reduced by CMP treatment.

4 is a photograph of a 4 inch wafer fabricated in such a process, and FIG. 5 is a TEM photograph of this sample. As shown in FIG. 5, in the case of the GaAs thin film manufactured by this method, it was confirmed that a single crystal was formed without defects caused by mismatch.

The present invention is not limited to the above-described specific preferred embodiments, and various modifications can be made by any person having ordinary skill in the art without departing from the gist of the present invention claimed in the claims. Of course, such changes will fall within the scope of the claims.

1A is a process chart of manufacturing a single crystal GaAs thin film combined with a silicon wafer according to one embodiment of the present invention,

1B is a process chart of manufacturing a single crystal GaAs thin film combined with a silicon wafer according to another embodiment of the present invention.

Figure 2 is a graph showing the peeling phenomenon according to the irradiation temperature and irradiation amount when the hydrogen ion implantation according to the present invention,

Figure 3a is a FE-SEM picture of the specimen produced according to the process of one embodiment of the present invention,

Figure 3b is a FE-SEM picture of the specimen prepared according to the process of another embodiment of the present invention,

Figure 4 is a 4 inch GaAs on SiO ₂ / Si wafer photograph produced by the process according to the invention,

5 is a cross-sectional TEM photograph of a GaAs on Si ₂ / Si wafer fabricated by this process.

Claims (9)

In the method of forming a single crystal GaAs thin film on a silicon wafer, Forming a silicon oxide layer on the GaAs wafer to be used as a buffer layer with the silicon wafer, An ion implantation step of irradiating ions to the GaAs wafer for peeling the GaAs wafer; Thereafter cleaning the GaAs wafer and the silicon wafer, and then bonding the GaAs wafer and the silicon wafer to each other by bonding the GaAs wafer and the silicon wafer to each other by applying pressure to the center; A method of manufacturing a single crystal GaAs thin film on a silicon wafer using an ion-cut technique and a wafer bonding technique, the method comprising the steps of: heat-treating the bonded GaAs wafer and the silicon wafer to release the ion-irradiated GaAs wafer. In the method of forming a single crystal GaAs thin film on a silicon wafer, An ion implantation step of irradiating ions to the GaAs wafer for peeling the GaAs wafer; Then forming a silicon oxide layer on the GaAs wafer to be used as a buffer layer with the silicon wafer; Thereafter cleaning the GaAs wafer and the silicon wafer, and then bonding the GaAs wafer and the silicon wafer to each other by bonding the GaAs wafer and the silicon wafer to each other by applying pressure to the center; A method of manufacturing a single crystal GaAs thin film on a silicon wafer using an ion-cut technique and a wafer bonding technique, the method comprising the steps of: heat-treating the bonded GaAs wafer and the silicon wafer to release the ion-irradiated GaAs wafer. The method according to claim 1 or 2, The ion implantation step is a method for producing a single crystal GaAs thin film on a silicon wafer using an ion-cut technique and a wafer bonding technique characterized in that the step of implanting hydrogen ions. The method according to claim 1 or 2, The ion implantation step is a step of implanting helium ions, characterized in that the single crystal GaAs thin film manufacturing method on a silicon wafer using ion-cut technology and wafer bonding technology by ion implantation. The method of claim 3, wherein Injecting the hydrogen ion is ion implantation, characterized in that to irradiate the hydrogen ion under the conditions of irradiation temperature 120 ~ 160 ℃, irradiation amount 1 ~ 2 x 10 ¹⁷ H ⁺ / cm ² to cause the GaAs wafer peeled off A method for producing a single crystal GaAs thin film on a silicon wafer using ion-cut technology and wafer bonding technology. The method of claim 4, wherein Injecting the helium ion is characterized in that the irradiation temperature is helium ions irradiated at room temperature (within 60 ℃), irradiation amount 1.8 ~ 5 x 10 ¹⁶ He ⁺ / cm ² in order to cause the peeling of the GaAs wafer A method of fabricating a single crystal GaAs thin film on a silicon wafer using ion-cut technology and ion bonding technology by ion implantation. The method of claim 1, Forming a silicon oxide layer on the GaAs wafer, Before ion implantation into a GaAs wafer, a dozens of Si ₃ N ₄ layers are grown on the surface by PECVD at a high temperature of 300 ° C. or higher, and then a SiO ₂ layer having a desired thickness (hundreds of kPa) is grown, and CMP (Chemical Mechnical) Single crystal GaAs thin film on a silicon wafer using ion-cut technology and wafer bonding technology, characterized in that the step of forming a SiO ₂ layer using PECVD and CMP to give a surface roughness of less than 5 하여 through a polishing process Manufacturing method. The method of claim 2, Forming a silicon oxide layer on the GaAs wafer, After ion implanted GaAs wafer was cleaned and rinsed in 5% HCl solution for 3 minutes and dried at 150 ℃ for 5 minutes, spin coating was applied on GaAs wafer using Methylphenyl-silsesquioxane (700F, Filmtronics). And then forming a SiO ₂ layer using SOG which is subjected to heat treatment at 150 ° C. for 5 minutes to give a surface roughness of about 5 Å; on the silicon wafer using ion-cut technology and wafer bonding technology by ion implantation. Monocrystalline GaAs thin film manufacturing method. The method according to claim 1 or 2, Peeling the ion-irradiated GaAs wafer is a step of heat treatment at 200 ~ 300 ℃ single-crystal GaAs thin film manufacturing method on a silicon wafer using ion-cut technology and wafer bonding technology by ion implantation.

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