WO2003000962A1

WO2003000962A1 - Silicon single crystal substrate, epitaxial wafer, and method for manufacturing them

Info

Publication number: WO2003000962A1
Application number: PCT/JP2002/006101
Authority: WO
Inventors: Makoto Iida
Original assignee: Shin-Etsu Handotai Co., Ltd.
Priority date: 2001-06-25
Filing date: 2002-06-19
Publication date: 2003-01-03
Also published as: JP2003002786A

Abstract

A silicon single crystal substrate is used as a substrate of an epitaxial wafer. The silicon single crystal substrate for an epitaxial wafer is characterized in that the substrate is a single crystal doped with nitrogen and heavily doped with boron, and grown under the condition that the V/G value (where V is the pulling speed, and G is the crystal temperature gradient) lies between the lower limit in the small dislocation region in the OSF ring region and the upper limit in the I-rich region. An epitaxial wafer having an epitaxial layer formed thereon is also disclosed. No crystal defect is present in the epitaxial surface of a p/p+-EP wafer having an epitaxial layer formed on a p+ substrate heavily heavily doped with boron and doped with nitrogen. As a result, an epitaxial wafer high in guttering ability, quality, and function is provided, and a method for manufacturing the same is provided.

Description

m Thin silicon ψ-product board, epitaxy

If manufacturing technology

The tree invention further enhances the gettering ability of bulk bunks, and has no defects in epitaxy, such as pZP + epitaxy (hereinafter referred to as pp +-κP). In some cases) and the method for producing silicon Ui II, which is the K plate.

11 Technology

A short circuit from the power supply to the ground may occur on the short path of the semiconductor device through a generator, and if this phenomenon occurs, it may occur. This is called a latchup because the device does not work unless the power is dropped. As a countermeasure, こ ρ +-\ i P ゥ eha is used in Icheon.

This p p + —E P ゥ A is a boron plate;

Utilizing the effect of gettering effect * on the P + plate, the low boron concentration (p-) epitaxy canola (hereafter referred to as “epipe”) can be applied to the P + plate. A) A p-ZP + epitaxy wafer with i formed. In recent years, _r- concentration boron has a gettering effect and _r- concentration boron promotes the precipitation of oxygen. Because of this, there are advantages such as gettering effect and improvement of strength of the board, and so it is used in high-performance devices.

In recent years, in order to add more functions to the substrate, ρ ρ +-、ゥハして窒素してたして窒素た窒素窒素窒素窒素窒素窒素窒素窒素窒素窒素 ¾ It has been studied.

On the other hand, the products with nitrogen doping have oxygen concentration, oxygen concentration, V / G [m m ² K. min] (where, V: pulling speed [mm / min; LG: ¹ , tM liquid boundary in the product] The axial force of the product from the melting λ in the vicinity of ίιί to 1400 X: | ή] ίί ,, ί Iji declination «LK / mm]) i, etc. ¹ :: ', Depending on the pulling conditions, a small dislocation cluster may be formed in a part of the OS-Ding territory. May be 4: In other words, the OSF ring region expands when 尜 is doped, and a very small amount of 従来^λ \: appears in the oS fiii region sub-branch in the conventional nitrogen-doped OSF region. (Even though it is not the I-rich fi region) (see [11 (b))). Then, these minute spots are left on the board: if present, the wafers will be turned into w in the process of forming the wafers, so that defects will be formed on the surface of the wafers. You.

In the case of p-no p--KP ゥ e-ha, p- ¾ pull up the product of Itakawa and set the V-no-G value of m to a large value, so that the OSV ring goes out of the product. Therefore, the generation of such epi defects has been suppressed by making the region where dislocations are generated less opaque on the board (Patent Application No. 1-2949543-, Patent No. 200 00-1910 47-, K. ornbcrger ot al. J. Crystal Growth 180 (1977) 343-352.).

On the other hand, it is already known that high-concentration boron doping causes a shift to the VG OS 'output; and the VG する' output; ornl) ergor et al. J. Crystal Growth 180 (1977) 343-352.).

Thus, we examined the change in VZG value due to the generation of the OSF ring due to the r¾ concentration boron and the generation of dislocations due to nitrogen doping.

(1) Even when ¾ 尜 is doped, the VZG value at which the OSV ring occurs as in M shifts to the higher V / G side.

(2) Even in this case, a fifi region where a small cluster occurs as in ['1] is formed in a part of the OSF ring region.

(3) It has been confirmed that such dislocations cannot be suppressed only by boron doping; In other words, when VZG is made into a p-plate and M like,; ';; ί ί,, ノ, Ρ,,,, 場合場合場合場合場合I was told that an episode was missing. Disclosure of the invention

Therefore, the present invention has been made in view of such a problem, and forms an epitaxy on a high-concentration boron-doped plate on which nitrogen is doped to form a Pp. + — When manufacturing EP wafers, epitaxy has been used to eliminate product defects and has excellent gettering ability. The main purpose is to provide.

To solve the above problems, shea Li co down i crystal substrate of the present ¾ Ming E pita Kisharuue Doha River, there in Shi Li co down i Ah ¹ i article substrate that Do and ¾ plate E pita Kisharuue Doha And the nitrogen and tE¾ concentration ports are dropped, and V is G (where V is the pulling speed, G is the product axis direction near the solid-liquid interface in the product) (It is assumed to be the degree gradient) The value is a product formed under the condition that the lower limit || '(and the upper limit value of the I-rich region) of the small dislocation generation region in the OSF ring region is determined. It is a feature.

The “high-concentration boron” in the present invention means that the boron concentration is low.

5 X 10 ¹⁷ atoms / cm ³ (less than .0 Ω · cm in resistivity).

Thus, nitrogen and high-concentration boron are doped and V / G fif'f

The lower limit fi of the micro-position generation area in the OSF ring area and the upper limit of the I-rich area were formed. Since the copper plate does not have a large dislocation generation region within the OSF ring region caused by the nitrogen doping on its surface, it does not have a large dislocation generation region. Even if Μ is loaded, there is no danger of forming defects in the epi table D¾ !, and an epitaxy wafer with quality and function can be provided.

In this case, the silicon-coated product has a resistivity of less than 0.02 Ω · cm and a concentration of doped nitride of 3 × 10 ¹³ cm ³ or more. This power is preferred.

In the case where the resistivity is 0.02 Ωcm or less, the value of Bon / Ji The effect is that the gettering effect due to the sufficiently high level of oxygen and the gettering effect due to the high concentration of boron accelerating the precipitation of oxygen and the strength of the substrate are improved. There is S.

Further, when the nitrogen concentration to be dropped is 3 × 10 is Z cm ³ or more, the oxygen precipitation characteristics can be further improved.

An epitaxial wafer of the present invention is obtained by growing an epitaxial layer on the above-mentioned silicon single crystal substrate, and includes an OSF ring region caused by nitrogen doping in the substrate. Since there is no micro dislocation generation region that is likely to occur in the substrate, even if an epitaxial layer is stacked on this substrate, there is no danger of forming a defect on the surface of the epitaxial layer, and a high quality, high performance epitaxial wafer Can be provided.

Further, the epitaxial wafer of the present invention is an epitaxial wafer in which an epitaxial layer is formed on a silicon single crystal substrate doped with nitrogen and a high concentration of boron. The feature is that there is no epitaxial layer defect caused by crystal defects of the substrate on the surface of the axial layer.

As described above, according to the present invention, it is possible to provide an epitaxy wafer having no epi layer defects despite the use of a high-concentration boron-doped substrate doped with nitrogen. . Therefore, an epitaxy wafer with extremely low IG capability with no epidemic defect is provided.

Further, the method for producing a silicon single crystal for epitaxial growth according to the present invention is a silicon single crystal doped with nitrogen and a high concentration of boron by the Czochralski method. When growing a crystal, a silicon single crystal is pulled under the condition that the VG value is between the lower limit of the small dislocation generation region in the OSF ring and the upper limit of the I-rich region. are doing.

Thus, when growing a silicon single crystal doped with nitrogen and a high concentration of boron by the CZ method, the V / G value is the lower limit of the microdislocation generation region in the OSF ring. Single crystal is pulled under the condition that the value is between I and the upper limit of the lithium region. Therefore, the silicon single crystal substrate manufactured from the single crystal does not have a microdislocation generation region which is likely to be generated in the OSF ring region caused by the nitrogen doping in the plane. Even if an epitaxial layer is stacked on the substrate, there is no danger of forming defects on the epi surface.

In this case, the resistivity of the grown sheet re co down monocrystalline 0. 0 2 Ω · cm or less, arbitrary preferable that the this to the nitrogen concentration ³ XI 0 ¹³ / cm 3 or more.

When the resistivity is set to 0.02 Ωcm or less, the gettering effect due to the sufficiently high boron concentration and the high concentration of boron promotes the precipitation of oxygen. This has advantages such as an improved gettering effect and improved substrate strength. Further, when the concentration of nitrogen to be doped is set to 3 × 10 ¹³ cm ³ or more, the oxygen precipitation characteristics can be further improved.

According to the method for producing an epitaxial wafer of the present invention, an epitaxial layer is grown on a substrate obtained by slicing a silicon single crystal produced by the above-described production method. According to such a manufacturing method, the silicon single crystal silicon wafer serving as a substrate has an O-type impurity caused by nitrogen doping.

Since there is no micro dislocation generation region that is likely to occur in the SF ring region, even if an epitaxial layer is deposited on this substrate, there is no danger of forming defects on the epi surface, and high quality and high performance We can provide an epitaxy wafer.

As described above, according to the present invention, even if the silicon single crystal substrate of the PP +-EP wafer is doped with nitrogen, the getter in which defects are eliminated from the surface of the epi layer is obtained. High quality, high performance epi wafers with extremely high ring capacity can be manufactured. BRIEF DESCRIPTION OF THE DRAWINGSFIG. 1 (a) is a view showing the change of crystal defects in the growth direction of nitrogen doping and heavily boron-doped crystal, and FIG. 1 (b) FIG. 4 is a view showing a state of distribution of crystal defects in a nitrogen-doped crystal growth direction of FIG. BEST MODE FOR CARRYING OUT THE INVENTION

Hereinafter, embodiments of the present invention will be described in more detail, but the present invention is not limited thereto.

The present inventors have found that even if an epitaxial layer is formed on a silicon single crystal substrate doped with a high concentration of boron for PZP + -EP wafers and also doped with nitrogen. In order to establish a method for manufacturing an epitaxial wafer in which no crystal defects are formed on the surface of the silicon layer, the present inventors have conducted intensive studies and experiments on silicon single crystal growth conditions, and examined the various conditions to determine the present invention. Completed.

If the pulling speed of the single crystal can be increased as high as possible, the remarkably large VZG value can drive the micro dislocation generation region to the periphery of the crystal even in a nitrogen-doped crystal. There is no problem because it can be done, but in reality, at a certain speed, the crystal becomes easily deformed, and there is a speed at which pulling at the mass production level becomes difficult. The parameter VZG value at this rate indicates that the nitrogen doping, and in the case of high boron concentration doping, the OSF ring and the generation of micro-dislocation generation regions in the region are still crystallized. It cannot be extinguished in the surrounding area.

Therefore, an OSF ring was placed inside the crystal, and an attempt was made to reduce the pulling speed so that micro dislocations did not occur.

In the case of a crystal having a normal resistance value, such a region is (1) extremely slow, and (2) there is an I-rich region immediately adjacent thereto, where the dislocation cluster is also high. It is usually not considered suitable for epitaxial growth substrates for two reasons: density exists (see Figure 1 (b)).

However, in the case of high-concentration boron bumps, the region where such small dislocations do not occur is relatively fast, and the V-G value, which is the I-rich region, is not so large. The fact that it did not increase was confirmed for nitrogen-doped and high-concentration boron-doped crystals.

In addition, the OSF generation region and the micro dislocation generation region inside it are boron In addition to the concentration, it was confirmed that it was affected by the nitrogen concentration and oxygen concentration. Therefore, when manufacturing a Ρ Ρ Ρ + — EP た wafer using a high-concentration boron 'nitrogen-doped substrate, the speed must be reduced to such a degree that micro dislocation regions in the OSF region do not occur. The result was that a crystal for a substrate should be manufactured while controlling the in-plane VG value so as not to form a one-rich region.

Based on the above results, the method for producing a silicon single crystal for epitaxial growth according to the present invention provides a silicon doped with nitrogen and a high concentration of boron by the Czochralski method. When growing a silicon single crystal, the silicon single crystal was pulled under conditions where the VZG value was between the lower limit of the microdislocation generation region in the OSF ring and the upper limit of the I-rich region. (See Fig. 1 (a)).

In a silicon single crystal substrate manufactured from a single crystal pulled under such conditions, there is a micro dislocation generation region in the plane, which is likely to occur in the OSF ring region caused by nitrogen doping. Therefore, even if an epitaxial layer is stacked on this substrate, there is no danger of forming crystal defects on the surface of the epitaxy, and it is possible to provide an epitaxy wafer having a very high gettering effect. And can be.

The calculation of V / G can be performed using FEMAG and taking into account HZ.

Here, FE MAG is described in the literature (F. D upret, P. Nicodeme, Y. Ryckmans, P. W outers, and M. J. Crochet, Int. J. Heat Mass Transfer, 33, 1849 (1990)) is a comprehensive heat transfer analysis software.

In this case, it is preferable that the silicon single crystal to be grown has a resistivity of 0.02 Ω · cm or less and a nitrogen concentration of 3 × 10 ¹³ Zcm ³ or more. Is set to 0.02 Ωcm or less, the gettering effect due to the high boron concentration and the gettering due to the high boron concentration accelerating the precipitation of oxygen. There are advantages such as the effect of improving the tiling effect and the strength of the substrate. However, since there is a solid solution limit of boron in a silicon single crystal, the lower limit of the resistance value is about 0.001 Ω · cm. Further, when the concentration of nitrogen to be dropped is set to 3 × 10 ¹³ cm ³ or more, the oxygen precipitation characteristics due to nitrogen can be sufficiently improved. If the concentration is lower than this, the oxygen precipitation effect due to nitrogen doping may be reduced. The upper limit is a concentration of about ⁵ × 10 ^: ⁵ / cm ^3, which does not hinder single crystallization of nitrogen.

In the present invention, the oxygen concentration in the crystal may be any concentration in principle. However, depending on the oxygen concentration, the manner in which a small dislocation loop is generated in the OSF ring is changed depending on the oxygen concentration, which affects the difficulty of pulling the VZG value within the range of the present invention. .

Specifically, if no oxygen is present, no nucleus of OSF is likely to be generated, and neither the 〇SF ring nor the small dislocation loop is generated. In addition, when the crystal is formed at an extremely low oxygen concentration and when the crystal is formed at a high oxygen concentration, the way of generating the OSF ring and the small dislocation loop is clearly different. Dislocations are likely to occur.

Therefore, in the present invention, an appropriate vZ

G value needs to be controlled.

According to the method of manufacturing an epitaxial wafer of the present invention, an epitaxial layer is grown on a wafer obtained by slicing a silicon single crystal manufactured by the above manufacturing method. . As a result, it is possible to provide an epitaxy wafer having an extremely high IG capability in which an epi layer having no epi defects is formed.

Hereinafter, the present invention will be described more specifically with reference to Examples and Comparative Examples, but the present invention is not limited thereto.

(Examples, Comparative Examples)

[Test 1 1] Specific HZ (Hot Z one, in single crystal pulling device) Using a pulling device having a furnace internal structure), 120 kg of the raw material silicon is charged, a predetermined amount of 膜 a wafer with a nitride film is charged, and the nitrogen concentration is set to 3 × 10 ¹³ / cm ³ ( Doped impurities (boron) so that the resistivity becomes 0.015 Ω · ς: πι at the shoulder of the single crystal rod, and calculate the oxygen concentration to about 1 at the shoulder of the single crystal rod. At 4 ppma (JEIDA standard, JEIDA: Japan Electronic Industry Development Association), a single crystal having a diameter of 20 Omm (8 inches) was pulled at a pulling speed of 1.0 mm.

OSF rings were widely distributed in the wafers cut from this single crystal, and microdislocations occurred in some of them (at V = 1.0 in Fig. 1 (a), VZG ^{= 0. 2 5 mm 2 ZK} 'min).

Furthermore, when a 5 μm epitaxial layer was grown at 110 ° C on a mirror-finished wafer fabricated by slicing from a straight body near the shoulder of the crystal, micro-dislocations were generated. Cross-sectional TEM observation revealed that there were epi defects on the surface of the epi layer corresponding to the eroded portion.

[Test-2] Then, using a pulling device having the same HZ structure as in Test-1, the pulling speed was reduced to 0. SO mmZmin under the same conditions, and the OSF was placed at the center of the wafer. However, micro-dislocations themselves were not generated (Fig. 1 (a), where V = 0.8, V / G = 0. SO mmZ ZK 'min A mirror wafer was fabricated from this crystal, and when an epitaxy layer was grown, defects were eliminated from the epi surface.

[Test 1-3] Finally, using the same pulling device with the same HZ structure as in Test 1, the pulling speed was reduced to 0.6 mm / min under the same conditions. (V / G = 0.15 mm ² / K ′ min, where V = 0.6 in FIG. 1 (a)). This region is a region where large dislocation clusters are generated, and defects are generated on the entire surface after epitaxy growth.

As a result of the above test, the silicon single crystal of the present invention for epitaxial growth was When growing a silicon single crystal doped with nitrogen and a high concentration of boron by the cZ method, the V-G value is determined by the lower limit of the microdislocation generation region in the OSF ring and the I-value. — It is only necessary to pull up the silicon single crystal under the condition of being within the upper limit of the lithium region, whereby a silicon single crystal substrate having no micro dislocation generation region can be manufactured. Was confirmed.

In addition, the region where dislocation does not occur greatly changes depending on boron concentration and nitrogen concentration. The nitrogen concentration at which sufficient BMD is obtained in the substrate is 3 XI 0 ¹³

/ cm ³ or more, it is desirable to use at this concentration from the viewpoint of improving gettering ability. In addition, when the resistivity is between the normal resistivity (1 to 20 Ω · cm) and the low resistivity (0.1 Ω · cm or less), the VZG value at which the OSF ring occurs does not increase so much. In addition, since the so-called N region does not expand, it is difficult to pull the crystal with the V / G value within the range of the present invention. Therefore, it is desirable to apply the method of the present invention within a resistivity of 0.1 Ω · cm or less, preferably, of 0.02 Ω · cm or less.

On the other hand, when the nitrogen concentration is as high as 1 XI 0 ¹⁴ / cm ³ or more, the region where micro dislocations occur is enlarged. By adjusting the HZ and flattening the in-plane distribution of the crystal axis temperature gradient G near the solid-liquid interface in the crystal, dislocations caused by nitrogen from the in-plane and the I-rich region Both dislocations need to be eliminated.

Note that the present invention is not limited to the above embodiment. The above embodiment is an exemplification, and any of those having substantially the same configuration as the technical idea described in the claims of the present invention and having the same function and effect can be obtained. Are also included in the technical scope of the present invention.

For example, in the above embodiment, the case where a silicon single crystal having a diameter of 200 mm (8 inches) is grown has been described by way of example. However, the present invention is not limited to this. It can also be applied to silicon single crystals of 100 to 400 mm (4 to 16 inches) or larger. Further, it goes without saying that the present invention can be applied to a so-called MCZ method in which a horizontal magnetic field, a vertical magnetic field, a cusp magnetic field, or the like is applied to a silicon melt.

Claims

The scope of the claims

1. A silicon single crystal substrate to be a substrate of an epitaxial wafer, which is doped with nitrogen and a high concentration of boron, and has a VZG (where, V: pulling speed, G: The temperature was defined as the temperature gradient in the direction of the crystal axis near the solid-liquid interface in the crystal. The value was between the lower limit of the microdislocation generation region in the OSF ring region and the upper limit of the I-rich region. A silicon single crystal substrate for an epitaxial wafer characterized by being a single crystal.

2. The silicon for an epitaxial wafer according to claim 1, wherein the silicon single crystal substrate has a resistivity of 0.02 Q'cm or less. Single crystal substrate.

3. The concentration of doped nitrogen claim 1 or characterized TO THE 3 XI 0 ^{1 3} / cm ³ or more is re co down for E pita key Sharuwe Doha according to claim 2 Single crystal substrate.

4. An epitaxy layer formed by growing an epitaxy layer on the silicon single crystal substrate according to any one of claims 1 to 3. No.

5. An epitaxial layer having an epitaxial layer formed on a silicon single crystal substrate doped with nitrogen and a high concentration of boron, wherein the surface of the epitaxial layer has crystal defects on the substrate. An epitaxial wafer characterized in that there are no epitaxial layer defects caused by the above.

6. When growing a silicon single crystal doped with nitrogen and high concentration of boron by the Czochralski method, the VZG value has a small dislocation generation region in the OSF ring. Under the condition between the lower limit of the I-rich region and the upper limit of the I-rich region. A method for producing a silicon single crystal for epitaxial growth, characterized by pulling a single crystal.

7. The resistivity of the sheet re co down single crystal to be grown 0. 0 2 Q 'cm or less, according to claim 6, characterized that you and the nitrogen concentration ³ XI 0 ¹³ / cm 3 or more sheet Manufacturing method of silicon single crystal.

8. A method for growing an epitaxial layer on a substrate obtained by slicing a silicon single crystal produced by the production method according to claim 6 or 7. A method for producing an epitaxial wafer characterized by the following.