JP2009038124A - Epitaxial wafer manufacturing method and epitaxial wafer - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method of manufacturing an epitaxial wafer wherein a low-resistivity ion implanted layer, a high-resistivity epitaxial layer and a region where the resistivity transits between such layers are sharply formed, and a problem of generating contamination due to heavy metal impurity is eliminated. <P>SOLUTION: Provided is the epitaxial wafer manufacturing method wherein an epitaxial layer is formed on a silicon single crystal substrate. In the method, only carbon ions are implanted into an N-type silicon single crystal substrate to form a carbon ion implanted layer, then, on the surface of the N-type silicon single crystal substrate whereupon the carbon ion implanted layer is formed, the epitaxial layer is formed so that the thickness of a region where resistivity transits from the epitaxial layer toward the carbon ion implanted layer is 2 μm or less. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to an epitaxial wafer in which an epitaxial layer is formed on a silicon single crystal substrate and a method for manufacturing the same.

  Most of the current semiconductor devices are manufactured from a single crystal substrate or an epitaxial wafer on which only one epitaxial layer is grown. From the viewpoint of manufacturing a semiconductor device, the epitaxial wafer can form an electrically active layer having a resistivity different from that of the substrate, so that the degree of freedom in designing the semiconductor device is large and the cause of crystal defects. There are many advantages such as a high-purity single crystal thin film having a low concentration of oxygen or carbon that can be formed to an arbitrary thickness.

  For this reason, it has been put to practical use in products such as high voltage semiconductor devices, bipolar integrated circuit devices, CCDs and the like. In particular, when an epitaxial wafer is used for a CCD, a CCD is formed by providing a high-resistance epitaxial layer of the same conductivity type on a low-resistance substrate, so that the CCD is directly formed on the high-resistance substrate without forming an epitaxial layer. Compared with the case where it is formed, there is a possibility that the substrate voltage as a voltage for an electronic shutter or the like is significantly reduced. In such an epitaxial wafer, conventionally, P is added as an impurity to the substrate.

  Furthermore, if a semiconductor device is formed with an epitaxial wafer in which two epitaxial layers of a low-resistance epitaxial layer and a high-resistance epitaxial layer are sequentially laminated on the substrate, there are no restrictions due to the characteristics of the substrate in principle. In addition, the non-uniformity of the impurity concentration of the substrate is not reflected in the characteristics of the semiconductor device, which is considered to be an ideal structure. In such an epitaxial wafer, conventionally, P is added as an impurity to the lower epitaxial layer.

  By the way, when a CCD is formed on an epitaxial wafer in which two epitaxial layers are laminated on a substrate, there is no effect of reducing the shutter voltage unless the film thickness of the upper epitaxial layer is 10 μm or less. The lower limit of the film thickness is 4 μm, which is a thickness necessary for forming a CCD.

  On the other hand, when the film thickness of the upper epitaxial layer is fixed to 8 μm and the impurity concentration is fixed to an optimum value operable as a CCD, the effect of reducing the shutter voltage is achieved unless the impurity concentration ratio is 10 times or more. There is no.

  However, P has a large diffusion coefficient. For this reason, in an epitaxial wafer having a single epitaxial layer, when high-temperature heat treatment is applied, P diffuses from the substrate to the epitaxial layer, and an epitaxial layer with a stable impurity concentration cannot be formed. In addition, since the epitaxial layer is a single layer, the non-uniformity of the impurity concentration of the substrate is reflected in the characteristics of the semiconductor device, and image unevenness occurs in the CCD. Therefore, a semiconductor device having uniform characteristics cannot be formed with this epitaxial wafer.

  Therefore, a technique has been disclosed in which As and C having a small diffusion coefficient are ion-implanted into a substrate and an epitaxial layer is formed on the implanted surface (see Patent Document 1). However, even though the diffusion coefficient of As is small, As is diffused from the As implantation layer to the upper epitaxial layer by the subsequent heat treatment, and the resistivity transition region between the epitaxial layer on the surface side and the As implantation layer is changed. It was difficult to sharpen. In addition, As has a safety problem and is not as common as a substrate to which P is added as an impurity.

  Furthermore, since contamination by heavy metal impurities generally occurs during the growth of the epitaxial layer, the generation lifetime of the electrically active layer due to contamination near the surface of the epitaxial wafer, that is, the time from generation of carriers to recombination is 5 ms or less, It is shorter than 10 ms of a substrate grown by a general CZ method. For this reason, it is difficult to form a semiconductor device having excellent characteristics, and an increase in white spots and dark current was recognized in the CCD.

JP-A-6-163410

  The present invention has been made in view of the above problem, and while sharpening the region where the resistivity transition between the low resistivity ion implantation layer and the high resistivity epitaxial layer, An object of the present invention is to provide a method for manufacturing an epitaxial wafer which does not cause the problem of contamination by heavy metal impurities.

  In order to solve the above-mentioned problems, the present invention provides an epitaxial wafer manufacturing method for forming an epitaxial layer on a silicon single crystal substrate, wherein a carbon ion implanted layer is formed by implanting only carbon ions into an N-type silicon single crystal substrate. Then, the epitaxial layer is formed on the surface of the N-type silicon single crystal substrate on which the carbon ion implanted layer is formed, and the thickness of the region where the resistivity transitions from the epitaxial layer to the carbon ion implanted layer is as follows: An epitaxial wafer manufacturing method characterized in that the thickness is 2 μm or less is provided.

  As described above, in the present invention, a carbon composite having an A-Type structure having a negative charge as shown in FIG. 2 is implanted into the carbon ion implanted layer by implanting carbon ions into the N-type silicon single crystal substrate. Is formed. FIG. 2 is a diagram showing an example of a carbon composite formed in the carbon ion implantation layer of the epitaxial wafer of the present invention. The carbon composite illustrated in FIG. 2 has a negative charge because some carbon bonds existing in the structure are insufficient. Therefore, the carbon ion implantation layer is negatively charged by the carbon composite. When a voltage is applied to the silicon single crystal substrate on which the carbon ion implanted layer is formed, negative charges are released from the carbon composite. That is, since the carbon composite plays a role as a donor, the resistivity of the carbon ion implanted layer is lowered, and can be made lower than the resistivity in the epitaxial layer on the surface side or the bulk of the silicon single crystal substrate.

  Further, in the manufacturing method of the present invention, carbon ions do not diffuse, and conversely, carbon ions aggregate in the carbon ion implanted layer during the crystallinity recovery heat treatment after the ion implantation, the epi process or the device process, and the carbon concentration It becomes possible to form such that the transition region of the resistivity between the epitaxial layer on the surface side and the carbon ion implantation layer is 2 μm or less.

  Since the only element to be implanted is carbon ions, the resistivity of the ion-implanted layer is sharper than that of the epitaxial layer or the substrate without implanting conventionally used elements such as As that have problems with diffusion and safety. Since it can be changed and the injection layer can be stabilized, the effects of the present invention can be obtained with a simpler manufacturing method than in the prior art.

The epitaxial layer is preferably formed so that the thickness of the epitaxial layer is 4 to 10 μm.
Thus, by setting the thickness of the epitaxial layer within the above range, for example, when a CCD is formed in the epitaxial layer in the device process, the shutter voltage can be reduced. That is, an epitaxial wafer capable of forming a semiconductor device with good characteristics can be manufactured.

Moreover, it is preferable that the dose amount into which the carbon ions are implanted is 1 × 10 ¹⁴ ions / cm ² or more.
Thus, by making the dose amount of carbon ions within the above range, the total number of carbon composites formed in the carbon ion implanted layer can be increased, thereby further reducing the resistivity of the carbon ion implanted layer. Therefore, the difference in resistivity between the epitaxial layer on the surface side and the carbon ion implanted layer can be increased.

Moreover, it is preferable that the resistivity of the epitaxial layer is 10 times or more than the resistivity of the carbon ion implanted layer.
Thus, by making a difference of 10 times or more between the resistivity of the epitaxial layer and the carbon ion implanted layer, it becomes possible to produce an epitaxial wafer in which the resistivity of the substrate and the epitaxial layer is significantly different from each other. It is possible to manufacture an epitaxial wafer that is not theoretically restricted by the above characteristics.

  The present invention is also an epitaxial wafer in which an epitaxial layer is formed on a silicon single crystal substrate, wherein the silicon single crystal substrate is N-type and only carbon ions are implanted from its surface to form a carbon ion implanted layer. The epitaxial layer is formed on the surface of the silicon single crystal substrate on which the carbon ion implantation layer is formed, and the resistivity transitions from the epitaxial layer to the carbon ion implantation layer. An epitaxial wafer is provided in which the thickness of the region to be processed is 2 μm or less (claim 5).

Thus, carbon ions are implanted, thereby forming a carbon composite having a negative charge in the carbon ion implanted layer, whereby the carbon ion implanted layer has a negative charge. And the resistivity of the carbon ion implantation layer in the silicon single crystal substrate on which the carbon ion implantation layer is formed decreases. In addition, carbon ions do not diffuse, and conversely, carbon ions aggregate in the carbon ion implanted layer during the epi process or device process, and the carbon concentration becomes high centering on the implantation depth. An epitaxial wafer having a resistivity transition region thickness of the carbon ion implantation layer of 2 μm or less can be obtained.
Then, only carbon ions are implanted, and it is not necessary to implant conventionally used elements such as As which have problems with diffusion and safety, and an epitaxial wafer having a sharp resistivity distribution can be obtained. it can.

The epitaxial layer preferably has a thickness of 4 to 10 μm.
Thus, by setting the thickness of the epitaxial layer in the above range, for example, when a CCD is formed in the epitaxial layer, the shutter voltage can be reduced. That is, an epitaxial wafer capable of forming a semiconductor device with good electrical characteristics can be obtained.

The silicon single crystal substrate preferably has a dose amount of the implanted carbon ions of 1 × 10 ¹⁴ ions / cm ² or more.
Thus, when the amount of carbon ions dosed is in the above range, the total number of carbon composites formed in the carbon ion implanted layer can be increased, thereby further reducing the resistivity of the carbon ion implanted layer. Therefore, the difference in resistivity between the epitaxial layer on the surface side and the carbon ion implanted layer can be further increased.

Moreover, it is preferable that the resistivity of the epitaxial layer is 10 times or more as compared with the resistivity of the carbon ion implanted layer.
As described above, the difference between the resistivity of the epitaxial layer and the carbon ion implanted layer is 10 times or more, so that the resistivity of the substrate and the epitaxial layer can be greatly and sharply different from each other. It is possible to make an epitaxial wafer in which there is no restriction by the principle.

As described above, in the present invention, carbon ions are implanted into an N-type silicon single crystal wafer, and then an epitaxial layer is formed on the carbon ion implanted surface. As a result, a carbon composite having a negative charge is formed in the carbon ion implanted layer, and the carbon composite can act as a carrier to reduce the resistivity of the carbon ion implanted layer. In addition, in the epi-growth process and device process, carbon ions agglomerate around the implantation depth and become a high concentration, and the resistivity of the carbon ion implanted layer further decreases, and the epitaxial layer on the surface side and the carbon ion implanted layer are further reduced. The resistivity transition region can be made as sharp as 2 μm or less. Thereby, an epitaxial wafer having two layers of a low resistivity layer and a high resistivity epitaxial layer can be obtained. Therefore, a semiconductor device having good characteristics can be manufactured on the surface of the epitaxial layer.
Then, since the effects of the present invention can be obtained by implanting only carbon ions, an epitaxial wafer that is safer and simpler than conventional methods and that has good electrical characteristics can be obtained. be able to.

Hereinafter, the present invention will be described more specifically.
As mentioned above, it has a low-resistance ion-implanted layer and a high-resistance epitaxial layer, and the region where the resistivity changes and transitions between them is sharp, and the problem of contamination by heavy metal impurities The development of a method for manufacturing an epitaxial wafer that does not generate the problem has been awaited.

  Therefore, the present inventors have intensively studied whether a problem can be solved by injecting a nonmetallic element having a small diffusion coefficient and no heavy metal contamination.

  As a result, when the present inventors ion-implanted carbon in the N-type silicon single crystal substrate, a carbon composite having a negative charge is formed in the carbon ion-implanted layer, and the carbon composite acts as a carrier. The resistivity of the carbon ion implanted layer can be changed, and furthermore, since the carbon composite is aggregated, the diffusion of carbon ions is suppressed, so that the carbon ion implanted layer can be stabilized. As a result, it has been found that an epitaxial wafer having two layers of a low resistivity layer and a high resistivity layer can be produced without using As which is problematic in diffusion and safety, and the present invention has been completed.

Hereinafter, the present invention will be described in more detail with reference to FIG. 1, but the present invention is not limited thereto. FIG. 1 is a cross-sectional explanatory view illustrating an epitaxial wafer of the present invention.
A carbon ion implantation layer 12 formed by implanting carbon ions into a silicon single crystal substrate 11 is made of interstitial carbon (C _i ), interstitial oxygen (O _i ), interstitial silicon (Si _I ), or the like. In other words, an epitaxial layer 13 is formed on the surface of the silicon single crystal substrate 11 on which the carbon ion implanted layer 12 is formed.
Here, examples of the carbon composite formed in the carbon ion implanted layer 12 by carbon ion implantation include C _i (Si _I ) _n and C _i O _i (Si _I ) _n .

  The epitaxial wafer of the present invention can be produced by the following steps, and an example thereof is shown below, but the method for producing the epitaxial wafer of the present invention is not limited to the following.

First, an N-type single crystal silicon substrate is prepared. This silicon substrate is usually produced by the CZ method, and examples of the dopant include P, As, and Sb.
A carbon ion implantation layer is formed on this silicon single crystal substrate by injecting only carbon ions into one of the main surfaces of this silicon single crystal substrate using a high current ion implanter without implanting As or the like. To do.
Here, carbon ions are the only elements implanted into the silicon single crystal substrate.

Here, the dose amount of carbon ions can be set to 1 × 10 ¹⁴ ions / cm ² or more.
By setting the dose in the above range, the total number of carbon composites formed in the carbon ion implanted layer can be increased, whereby the resistivity of the carbon ion implanted layer can be further reduced, and the surface side The difference in resistivity between the epitaxial layer and the carbon ion implanted layer can be increased.
Further, since the resistivity can be changed in correlation with the carbon ion dose, the dose of carbon ions can be selected so as to obtain a desired resistivity. Thus, the resistivity of the ion implantation layer can be controlled by the carbon ion implantation amount.

After this carbon ion implantation, it is preferable to perform a crystalline recovery heat treatment by an RTA apparatus.
By performing the crystallinity recovery heat treatment in this way, it is possible to recover the crystallinity of the substrate disturbed by the carbon ion implantation, which causes epi defects when the epitaxial layer is formed on the wafer surface. This can be suppressed. It is also possible to form a carbon composite at this stage to sharpen the carbon concentration distribution (resistivity distribution).

Thereafter, an epitaxial layer is formed on the surface implanted with carbon ions. General conditions can be used to form the epitaxial layer.
For example, a source gas such as SiHCl ₃ is introduced into the chamber using H ₂ as a carrier gas, and epitaxial growth is performed by CVD at about 1050 to 1250 ° C. on a wafer having a carbon ion implantation layer disposed on the susceptor. Can do.

Here, the thickness of the formed epitaxial layer can be 4 to 10 μm.
By setting the thickness of the epitaxial layer within the above range, for example, when a CCD is formed in the epitaxial layer in the device process, the shutter voltage can be reduced. That is, an epitaxial wafer that can form a semiconductor device having good electrical characteristics can be manufactured.

Moreover, in this invention, an epitaxial wafer is produced so that the thickness of the area | region where a resistivity transitions from an epitaxial layer to a carbon ion implantation layer may be set to 2 micrometers or less.
By making the thickness of the region where the resistivity changes in the depth direction and transitions to 2 μm or less, the resistivity transition region can be made sharper than the conventional one, which makes epitaxials with good electrical characteristics. A wafer can be fabricated.

In addition, the resistivity of the formed epitaxial layer can be made 10 times or more that of the carbon ion implanted layer.
This makes it possible to produce an epitaxial wafer having two layers with different resistivity, and an epitaxial wafer that is not theoretically restricted by the characteristics of the substrate can be obtained.

  As described above, according to the present invention, a carbon composite having a negative A-type structure is formed in the carbon ion implanted layer, and the carbon ion implanted layer is negatively charged by the carbon composite. . When a voltage is applied to the silicon single crystal substrate on which the carbon ion implanted layer is formed, negative charges are released from the carbon composite. That is, since the carbon composite plays a role as a donor, the resistivity of the carbon ion implanted layer is lowered, and can be made lower than the resistivity in the epitaxial layer on the surface side or the bulk of the silicon single crystal substrate.

  Further, in the epitaxial wafer of the present invention, almost no diffusion of carbon ions from the carbon ion implanted layer occurs. Conversely, carbon ions aggregate in the carbon ion implanted layer during the recovery heat treatment or epi process, and the carbon concentration becomes the implantation depth. It becomes possible to make the transition region of resistivity between the epitaxial layer on the surface side and the carbon ion implanted layer extremely sharp. Moreover, since the carbon composite aggregates, an effect of suppressing the diffusion of carbon from the carbon ion implanted layer is obtained, so that the resistivity of the carbon ion implanted layer can be prevented from changing.

As described above, the resistivity of the carbon ion implanted layer can be changed as compared with that in the epitaxial layer or the substrate bulk, and the thickness of the region where the resistivity transition can be reduced, and the resistivity is Since it can be made stable, according to the present invention, an epitaxial wafer having layers with different resistivity can be easily obtained. Since the electrical characteristics are uniform and stable, a device having good performance can be obtained by manufacturing a semiconductor device on the surface of such an epitaxial wafer.
Due to the effects described above, there is a problem in diffusion and safety during heat treatment, and there are two layers of a low resistivity layer and a high resistivity epitaxial layer without using As, Sb, etc., which can be heavy metal impurities. An epitaxial wafer can be produced.

  Furthermore, since the carbon ion implantation layer is formed immediately below the epitaxial layer, the gettering effect is also high. In particular, in the present invention, since the region where the resistivity transitions from the epitaxial layer to the carbon ion implantation layer is sharp, the gettering effect is also concentrated and the effect is more significant.

EXAMPLES Hereinafter, although an Example and a comparative example are shown and this invention is demonstrated more concretely, this invention is not limited to these.
(Example 1)
First, an N-type silicon single crystal substrate having a diameter of 200 mm was prepared. The resistivity of the prepared N-type silicon single crystal substrate was 10 Ωcm, the thickness of the natural oxide film on the surface was 25 nm, and P was used as the dopant.
Next, carbon was ion-implanted into the single crystal substrate using a high-current ion implanter under the conditions of a dose of 1 × 10 ¹⁵ atoms / cm ² and an acceleration energy of 80 keV to form a carbon ion implanted layer.
Thereafter, heat treatment was performed for crystallinity recovery at 1175 ° C. for 30 seconds using a rapid heating / rapid cooling (RTA) apparatus in an argon atmosphere with an ammonia concentration of 1.0%.
Thereafter, an epitaxial layer was formed on the surface of the single crystal substrate on which the carbon ion implanted layer was formed under the processing conditions of 1130 ° C., and an epitaxial wafer was manufactured. The thickness of the formed epitaxial layer was about 6 μm.

Thereafter, the produced epitaxial wafer was evaluated by the following method.
In order to evaluate the carbon concentration distribution in the depth direction from the surface of the produced epitaxial layer, the carbon concentration was evaluated by secondary ion mass spectrometry. Here, in order to evaluate the state of the epitaxial wafer of the present invention after the device heat treatment, a two-step heat treatment corresponding to the device heat treatment was performed. The conditions were 800 ° C. for 4 hours and 1000 ° C. for 16 hours in a mixed gas atmosphere of nitrogen (97%) and oxygen (3%). The wafer to be measured was the wafer before and after performing the heat treatment described above. The result is shown in FIG. FIG. 3 is a view showing an example of a carbon concentration distribution in the depth direction from the surface before and after device heat treatment of the epitaxial wafer according to Example 1 of the present invention.
Further, in order to evaluate the resistivity distribution and the carrier concentration distribution in the depth direction of the manufactured epitaxial wafer, a transition region in which the resistivity in the depth direction of the epitaxial wafer is changed by the SR method and the SCM (Scanning Capacitance Microscope) method. Evaluated. The result is shown in FIG. FIG. 5 is a diagram showing a change in resistivity in the depth direction from the surface of an epitaxial wafer of an example of the present invention and a comparative example described later.

  As shown in FIG. 3, in the epitaxial wafer of Example 1, after the formation of the epitaxial layer, carbon is concentrated near the implantation depth, and the change in concentration distribution is smooth. I understand more. In the epitaxial wafer after the heat treatment, carbon was concentrated and distributed near the implantation depth, and a sharp peak was observed near the implantation depth.

  FIG. 4 shows how the concentration distribution in the depth direction of the implanted elements implanted in the epitaxial wafer of the present invention and the prior art changes based on the evaluation results of FIG. 3 in the subsequent processing steps. FIG. FIG. 4A is a diagram showing how the concentration distribution of the implanted element in the depth direction in the epitaxial wafer of the present invention changes depending on the process. FIG. 4B is a diagram showing a change in concentration distribution of a comparative example shown later.

  As shown in FIG. 4A, in the epitaxial wafer of the present invention, the implanted carbon element has a Maxwell distribution centering on the implantation depth immediately after ion implantation into the substrate. Thereafter, when the epitaxial layer is formed, the temperature of the substrate becomes high, so that a small amount of the implanted carbon diffuses in the direction of the epitaxial layer or the single crystal substrate. The effect increases the carbon concentration around the implantation depth. Furthermore, a part of the device is further diffused outside the implantation layer by the device heat treatment, but the concentration distribution becomes a sharper distribution centering on the implantation depth due to the aggregation effect.

  On the other hand, as shown in FIG. 4B, in the case of the conventional technique in which P or As is ion-implanted, the Maxwell distribution is centered on the implantation depth immediately after the ion implantation as in the present invention. Each time heat is applied to the substrate, such as layer formation or device heat treatment, the implanted element diffuses to the outside, such as the epitaxial layer or single crystal substrate, so the concentration distribution has become more gradual. Go. In other words, the concentration distribution gradually changes and changes, which means that the ion implantation layer changes, and as a result, the resistivity of the implantation layer and the resistivity of the wafer itself change. . The occurrence of such a change is very inconvenient when manufacturing a semiconductor device on a wafer.

(Comparative Examples 1 and 2)
In Example 1, before carbon ions are implanted, As is implanted into a single crystal substrate using a high current ion implanter under conditions of a dose amount of 1 × 10 ¹³ atoms / cm ² and an acceleration energy of 180 keV. An epitaxial wafer was produced under the same conditions as in Example 1 except that (Comparative Example 1) was performed. And the change of the resistivity of the depth direction of an epitaxial wafer was evaluated with the evaluation method similar to Example 1. FIG.
Further, in place of carbon ion implantation in Example 1, only As was implanted into a single crystal substrate at a dose of 1 × 10 ¹³ atoms / cm ² and an acceleration energy of 180 keV using a high current ion implanter. An epitaxial wafer was produced under the same conditions as in Example 1 except that ion implantation was performed (Comparative Example 2). And the change of the resistivity of the depth direction of an epitaxial wafer was evaluated with the evaluation method similar to Example 1. FIG.

As a result, in the epitaxial wafer of Example 1, the thickness of the region where the resistivity transitions from the epitaxial layer to the carbon ion implantation layer (the region where the resistivity changes from the resistivity of the epitaxial layer to the lowest resistivity of the ion implantation layer). ) Was 1.4 μm, and the thickness of the transition region of the epitaxial wafer of Comparative Example 1 was 3.2 μm. The thickness of the transition region of the epitaxial wafer of Comparative Example 2 was 3.2 μm.
Thus, in the present invention, the region where the resistivity transitions from the epitaxial layer to the carbon ion implanted layer can be made 2 μm or less, and if the transition region can be made 2 μm or less in this way, the film thickness of the epitaxial layer is increased. 10 μm or less, the resistivity in the device formation region can be made uniform, and the region where the resistivity transitions from the epitaxial layer to the carbon ion implantation layer is sufficiently sharp compared to the conventional case, and the sufficient IG effect and Advantages in device design can be obtained.
From this result, the epitaxial wafer of the example can extremely sharpen the region where the resistivity transitions compared with the epitaxial wafer of the comparative example.

(Example 2)
In Example 1, an epitaxial wafer was produced under the same conditions as in Example 1 except that the dose amount of carbon ions was 5 × 10 ¹³ , 1 × 10 ^{14, and} 5 × 10 ¹⁴ ions / cm ² . Then, as in Example 1, the resistivity of the epitaxial wafer was measured.

The resistivity of the carbon ion implantation layer of the epitaxial wafers of Examples 1 and 2 is shown in FIG. FIG. 6 is a diagram showing an example of the relationship of the resistivity of the carbon ion implanted layer with respect to the carbon ion dose.
The resistivity of the carbon ion implanted layer of the epitaxial wafer of Example 1 is 0.04 Ωcm, and the resistivity of the carbon ion implanted layer having a dose of 1 × 10 ¹⁴ ions / cm ² in the epitaxial wafer of Example 2 is 15 Ωcm. there were. Thus, the resistivity of the carbon ion implanted layer can be changed by changing the dose of carbon ions.

  The present invention is not limited to the above embodiment. The above-described embodiment is an exemplification, and the present invention has any configuration that has substantially the same configuration as the technical idea described in the claims of the present invention and that exhibits the same effects. Are included in the technical scope.

It is sectional explanatory drawing explaining the epitaxial wafer of this invention. It is a figure which shows an example of the carbon composite_body | complex formed in the carbon ion implantation layer of the epitaxial wafer of this invention. It is a figure which shows an example of the carbon concentration distribution of the depth direction from the surface before and behind the device heat processing of the epitaxial wafer of this invention. It is a figure of transition of the concentration distribution of the implantation impurity element of the depth direction from the surface of the epitaxial wafer of this invention and a prior art. It is the figure which showed the transition of the resistivity of the depth direction from the surface of the epitaxial wafer of an Example and a comparative example. It is a figure which shows an example of the relationship of the resistivity of the carbon ion implantation layer with respect to the carbon ion dose amount in an Example.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 11 ... Silicon single crystal substrate, 12 ... Carbon ion implantation layer, 13 ... Epitaxial layer.

Claims (8)

  An epitaxial wafer manufacturing method for forming an epitaxial layer on a silicon single crystal substrate, in which only carbon ions are implanted into an N-type silicon single crystal substrate to form a carbon ion implanted layer, and then the carbon ion implanted layer is formed. The epitaxial layer is formed on the surface of the N-type silicon single crystal substrate, and the thickness of the region where the resistivity transitions from the epitaxial layer to the carbon ion implanted layer is 2 μm or less. A method of manufacturing an epitaxial wafer.   2. The method for producing an epitaxial wafer according to claim 1, wherein the epitaxial layer is formed so that the thickness of the epitaxial layer is 4 to 10 [mu] m. 3. The method of manufacturing an epitaxial wafer according to claim 1, wherein a dose amount for implanting the carbon ions is 1 × 10 ¹⁴ ions / cm ² or more. 4.   The epitaxial wafer manufacturing method according to any one of claims 1 to 3, wherein the resistivity of the epitaxial layer is set to be 10 times or more that of the carbon ion implanted layer. Method.   An epitaxial wafer in which an epitaxial layer is formed on a silicon single crystal substrate, wherein the silicon single crystal substrate is N-type, and only carbon ions are implanted from the surface thereof to form a carbon ion implanted layer, The epitaxial layer is formed on the surface of the silicon single crystal substrate on which the carbon ion implanted layer is formed, and the thickness of the region where the resistivity transitions from the epitaxial layer to the carbon ion implanted layer is An epitaxial wafer having a thickness of 2 μm or less.   The epitaxial wafer according to claim 5, wherein the epitaxial layer has a thickness of 4 to 10 μm. 7. The epitaxial wafer according to claim 5, wherein the silicon single crystal substrate has a dose amount of the implanted carbon ions of 1 × 10 ¹⁴ ions / cm ² or more.   8. The epitaxial wafer according to claim 5, wherein the resistivity of the epitaxial layer is 10 times or more as compared with the resistivity of the carbon ion implanted layer. 9.

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