WO2012101968A1 - Method for manufacturing silicon epitaxial wafer - Google Patents
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- WO2012101968A1 WO2012101968A1 PCT/JP2012/000139 JP2012000139W WO2012101968A1 WO 2012101968 A1 WO2012101968 A1 WO 2012101968A1 JP 2012000139 W JP2012000139 W JP 2012000139W WO 2012101968 A1 WO2012101968 A1 WO 2012101968A1
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- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
- H01L21/00—Processes or apparatus adapted for the manufacture or treatment of semiconductor or solid state devices or of parts thereof
- H01L21/02—Manufacture or treatment of semiconductor devices or of parts thereof
- H01L21/02104—Forming layers
- H01L21/02365—Forming inorganic semiconducting materials on a substrate
- H01L21/02367—Substrates
- H01L21/0237—Materials
- H01L21/02373—Group 14 semiconducting materials
- H01L21/02381—Silicon, silicon germanium, germanium
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- C—CHEMISTRY; METALLURGY
- C30—CRYSTAL GROWTH
- C30B—SINGLE-CRYSTAL GROWTH; UNIDIRECTIONAL SOLIDIFICATION OF EUTECTIC MATERIAL OR UNIDIRECTIONAL DEMIXING OF EUTECTOID MATERIAL; REFINING BY ZONE-MELTING OF MATERIAL; PRODUCTION OF A HOMOGENEOUS POLYCRYSTALLINE MATERIAL WITH DEFINED STRUCTURE; SINGLE CRYSTALS OR HOMOGENEOUS POLYCRYSTALLINE MATERIAL WITH DEFINED STRUCTURE; AFTER-TREATMENT OF SINGLE CRYSTALS OR A HOMOGENEOUS POLYCRYSTALLINE MATERIAL WITH DEFINED STRUCTURE; APPARATUS THEREFOR
- C30B25/00—Single-crystal growth by chemical reaction of reactive gases, e.g. chemical vapour-deposition growth
- C30B25/02—Epitaxial-layer growth
- C30B25/18—Epitaxial-layer growth characterised by the substrate
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- C—CHEMISTRY; METALLURGY
- C30—CRYSTAL GROWTH
- C30B—SINGLE-CRYSTAL GROWTH; UNIDIRECTIONAL SOLIDIFICATION OF EUTECTIC MATERIAL OR UNIDIRECTIONAL DEMIXING OF EUTECTOID MATERIAL; REFINING BY ZONE-MELTING OF MATERIAL; PRODUCTION OF A HOMOGENEOUS POLYCRYSTALLINE MATERIAL WITH DEFINED STRUCTURE; SINGLE CRYSTALS OR HOMOGENEOUS POLYCRYSTALLINE MATERIAL WITH DEFINED STRUCTURE; AFTER-TREATMENT OF SINGLE CRYSTALS OR A HOMOGENEOUS POLYCRYSTALLINE MATERIAL WITH DEFINED STRUCTURE; APPARATUS THEREFOR
- C30B29/00—Single crystals or homogeneous polycrystalline material with defined structure characterised by the material or by their shape
- C30B29/02—Elements
- C30B29/06—Silicon
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- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
- H01L21/00—Processes or apparatus adapted for the manufacture or treatment of semiconductor or solid state devices or of parts thereof
- H01L21/02—Manufacture or treatment of semiconductor devices or of parts thereof
- H01L21/02104—Forming layers
- H01L21/02365—Forming inorganic semiconducting materials on a substrate
- H01L21/02518—Deposited layers
- H01L21/02521—Materials
- H01L21/02524—Group 14 semiconducting materials
- H01L21/02532—Silicon, silicon germanium, germanium
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- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
- H01L21/00—Processes or apparatus adapted for the manufacture or treatment of semiconductor or solid state devices or of parts thereof
- H01L21/02—Manufacture or treatment of semiconductor devices or of parts thereof
- H01L21/02104—Forming layers
- H01L21/02365—Forming inorganic semiconducting materials on a substrate
- H01L21/02612—Formation types
- H01L21/02617—Deposition types
- H01L21/0262—Reduction or decomposition of gaseous compounds, e.g. CVD
Definitions
- the present invention relates to a method for manufacturing a silicon epitaxial wafer in which a silicon single crystal is epitaxially grown on a silicon single crystal substrate and an epitaxial layer is laminated.
- a silicon epitaxial wafer (hereinafter simply referred to as “epitaxial wafer”) is manufactured, for example, as follows.
- a silicon single crystal substrate is placed in a reaction vessel of a vapor phase growth apparatus, and the temperature in the reaction vessel is raised to 1000 ° C. to 1200 ° C. in a state where hydrogen gas is allowed to flow (temperature raising step).
- the temperature in the reaction vessel reaches 1000 ° C. or higher, the natural oxide film (SiO 2 : Silicon Dioxide) formed on the substrate surface is removed.
- a silicon source gas such as trichlorosilane (SiHCl 3 : Trichlorosilane), a dopant gas such as diborane (B 2 H 6 : Diborane), phosphine (PH 3 : Phosphine), arsine (AsH 3 : Arsine), or the like is used. It is supplied into the reaction vessel as a process gas together with the gas. In this way, the epitaxial layer is vapor-phase grown on the main surface of the substrate (epi growth process). After vapor phase growth of the epitaxial layer in this way, the supply of the silicon source gas and the dopant gas is stopped, and the temperature in the reaction vessel is lowered while maintaining the hydrogen atmosphere (cooling step).
- SiHCl 3 Trichlorosilane
- a dopant gas such as diborane (B 2 H 6 : Diborane), phosphine (PH 3 : Phosphine), arsine (AsH 3 : Arsine
- film thickness distribution and resistivity distribution
- the substrate is annealed at a high temperature of 1000 ° C. or higher, so outgas containing dopant is generated from the substrate. Outgas is generated particularly from the back surface of the substrate and goes around to the front surface side. Vapor phase growth on the surface is performed by a process gas, but the outgas that has entered from the back of the substrate is mixed with the process gas and taken into the growing epitaxial layer (hereinafter referred to as “auto-dope”).
- Patent Document 1 a laminar carrier gas having a gas flow rate of 2 m / min or more in the processing furnace or a gas replacement frequency of 3 times / min or more is flowed down.
- Patent Document 1 a laminar carrier gas having a gas flow rate of 2 m / min or more in the processing furnace or a gas replacement frequency of 3 times / min or more is flowed down.
- Patent Document 1 it has been very difficult to significantly reduce the amount of autodope.
- N / N ++++ (about 5 ⁇ 10 19 atoms / cm 3 ) epitaxial wafers using CZ crystals doped with a large amount of red phosphorus as an epitaxial substrate have attracted attention as a mainstream in the future.
- phosphorus has a high diffusion coefficient in Si, it is easily diffused by heat treatment in the epi-growth process, and auto-doping from the back surface tends to cause a decrease in the resistivity of the epitaxial layer and a transition region profile. There was a problem.
- the present invention has been made in view of such problems, and silicon epitaxial that can suppress an autodoping amount from a silicon single crystal substrate to an epitaxial layer during epitaxial growth and can obtain an epitaxial wafer having a good resistance distribution.
- An object is to provide a method for manufacturing a wafer.
- the resistivity is 0.5 m ⁇ ⁇ cm or more and 10.0 m ⁇ .
- the resistivity is 0.5 ⁇ ⁇ cm or more and 2000 ⁇ ⁇ cm or less on the silicon single crystal substrate doped with phosphorus or arsenic at a growth rate of 3 ⁇ m / min or more and 15 ⁇ m / min or less.
- a method for producing a silicon epitaxial wafer is provided, wherein the epitaxial layer is grown.
- a substrate having a very low resistance such as a substrate doped with red phosphorus or a substrate doped with arsenic
- the influence can be suppressed to the minimum, and an epitaxial wafer having a good resistance distribution can be manufactured.
- the growth rate of the epitaxial layer is set to a high rate of 3 ⁇ m / min or more, productivity and yield can be improved.
- the growth rate by setting the growth rate to 15 ⁇ m / min or less, it is possible to suppress generation of HCl gas that inhibits epitaxial growth due to the reaction between the silicon source gas and hydrogen gas, and stable epitaxial growth can be achieved.
- the resistivity of the silicon single crystal substrate is 0.5 m ⁇ ⁇ cm to 10.0 m ⁇ ⁇ cm
- the resistivity of the epitaxial layer formed thereon is 0.5 ⁇ ⁇ cm to 2000 ⁇ ⁇ cm. If it is such an epitaxial wafer, since it is easy to be influenced especially by auto dope, the manufacturing method of this invention is suitable.
- the growth temperature at the time of the epitaxial growth is 1000 ° C. or higher.
- the natural oxide film on the silicon single crystal substrate can be reliably removed, and an epitaxial wafer with a better film thickness distribution can be obtained on the silicon single crystal substrate.
- the growth rate of the epitaxial layer is preferably 5 ⁇ m / min or more and 15 ⁇ m / min or less.
- a correlation between the amount of auto-doping from the silicon single crystal substrate to the epitaxial layer and the growth rate of the epitaxial layer is obtained in advance, and the growth rate of the epitaxial layer is determined from the correlation. Can do.
- the epitaxial growth can be performed at a growth rate capable of making the resistance distribution at the center and edge portion of the epitaxial wafer more uniform and more efficient, silicon source gas or carrier gas is allowed to flow more than necessary, It is possible to prevent the temperature in the furnace from being raised excessively, and it is possible to further reduce the cost while reliably manufacturing an epitaxial wafer having a better resistance distribution.
- FIG. 4 is a view showing a flowchart of an example of the method for producing a silicon epitaxial wafer of the present invention.
- the silicon source gas is increased without changing the growth temperature of the epitaxial layer for high-speed growth.
- the growth may be performed at a higher growth temperature without changing the amount of the silicon source gas.
- the growth temperature may be further increased after increasing the silicon source gas.
- a silicon single crystal substrate doped with phosphorus having a resistivity of 0.5 m ⁇ ⁇ cm to 10.0 m ⁇ ⁇ cm is used. Place (preparation process). At this time, the silicon single crystal substrate is preferably manufactured from a CZ crystal doped with red phosphorus. Further, arsenic may be doped instead of phosphorus.
- the temperature in the reaction vessel is raised to a growth temperature for vapor-phase growth of the epitaxial layer (temperature raising step). This growth temperature is set to 1000 ° C. or higher at which the natural oxide film on the substrate surface can be reliably removed with hydrogen. In this case, the upper limit is not particularly limited, but if it is 1300 ° C. or lower, the occurrence of slip and the occurrence of contamination can be suppressed.
- the silicon raw material gas and the dopant gas are supplied at a predetermined flow rate together with the hydrogen gas, and the growth rate is 3 ⁇ m / min or more and 15 ⁇ m / min or less, more preferably 5 ⁇ m / min or more.
- An epitaxial layer having a resistivity of 0.5 ⁇ ⁇ cm to 2000 ⁇ ⁇ cm is grown at 15 ⁇ m / min or less, more preferably 6 ⁇ m / min or more and 15 ⁇ m / min or less until the film thickness reaches a predetermined thickness (epi growth process).
- the silicon source gas is increased 1.5 times to 4.0 times compared to the normal growth rate.
- the epitaxial layer is grown at a high growth rate of 3 ⁇ m / min to 15 ⁇ m / min even at a high temperature of 1000 ° C. or higher, so that the amount of dopants doped in the substrate is suppressed, An epitaxial layer having a good resistance distribution and film thickness distribution can be stably grown.
- a correlation between the amount of autodope from the substrate to the epitaxial layer and the growth rate of the epitaxial layer may be obtained in advance, and the growth rate may be determined based on the correlation.
- the growth temperature is set to 1100 ° C.
- the growth rate is changed by changing the flow rate of trichlorosilane gas, which is a silicon source gas.
- the epitaxial layer was stacked while changing the thickness between 1 and 9 ⁇ m / min.
- a correlation as shown in FIG. 1 was obtained between the autodoping amount and the growth rate.
- the amount of auto-doping is suppressed compared to the case where epitaxial growth is performed at a normal growth rate of 2 ⁇ m / min or less. I understand. Further, if it is 5 ⁇ m / min or more, the amount of auto-doping is suppressed more effectively, and if it is 6 ⁇ m / min or more, auto-doping hardly occurs, and the resistivity at the edge portion and the center portion of the epitaxial wafer is hardly increased. It can be seen that the difference disappears and the resistance distribution and the film thickness distribution are almost uniform.
- the temperature in the reaction vessel is lowered to cool the epitaxial wafer to the take-out temperature (cooling process).
- the hydrogen atmosphere is switched to the nitrogen atmosphere between about 800 ° C. and 400 ° C. And if it takes out temperature in nitrogen atmosphere, an epitaxial wafer will be taken out from a vapor phase growth apparatus (takeout process).
- the extracted epitaxial wafer is appropriately cleaned such as RCA cleaning (cleaning process).
- RCA cleaning cleaning process
- a cleaning method in this cleaning step in addition to a typical RCA cleaning, a method in which the concentration and type of a chemical solution are changed within a normal range can be used.
- Example 1 An epitaxial layer having a resistivity of 1.5 ⁇ ⁇ cm and a thickness of 1 ⁇ m on a silicon single crystal substrate having a resistivity of 1.0 m ⁇ ⁇ cm and doped with phosphorus and having a diameter of 200 mm is grown at a growth temperature of 1100 ° C. and a growth rate. Was grown at a high speed of 6 ⁇ m / min to produce an epitaxial wafer. Thereafter, the resistivity of the manufactured epitaxial wafer was measured in the radial direction. The result at this time is shown in FIG.
- Example 2 An epitaxial layer having a resistivity of 2.0 ⁇ ⁇ cm and a thickness of 1 ⁇ m on a silicon single crystal substrate having a resistivity of 2.0 m ⁇ ⁇ cm and doped with arsenic and having a diameter of 200 mm is grown at a growth temperature of 1100 ° C. and a growth rate. Was grown at a high speed of 6 ⁇ m / min to produce an epitaxial wafer. Thereafter, the resistivity of the manufactured epitaxial wafer was measured in the radial direction. The result at this time is shown in FIG.
- Example 1 An epitaxial wafer was manufactured in the same manner as in Example 1 except that the growth rate was 2 ⁇ m / min, and then the resistivity of the manufactured epitaxial wafer was measured in the radial direction. The results at this time are also shown in FIG.
- Example 2 An epitaxial wafer was manufactured in the same manner as in Example 2 except that the growth rate was 2 ⁇ m / min, and then the resistivity of the manufactured epitaxial wafer was measured in the radial direction. The results at this time are also shown in FIG.
- the present invention is not limited to the above embodiment.
- the vapor phase growth apparatus for vapor growth of the epitaxial layer in the present invention is not limited, and can be applied to various vapor phase growth apparatuses such as a vertical type (pancake type), a barrel type (cylinder type), and a single wafer type. is there.
- a vertical type pancake type
- a barrel type cylinder type
- a single wafer type a single wafer type.
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Abstract
In this method for manufacturing a silicon epitaxial wafer, an epitaxial layer is laminated by epitaxially growing a silicon single crystal on a silicon single crystal substrate. The method is characterized in that the epitaxial layer having a resistivity of 0.5-2,000 Ω∙cm is grown at a growing speed of 3-15 μm/min, on the silicon single crystal substrate, which has a resistivity of 0.5-10.0 mΩ∙cm, and which is doped with phosphorus or arsenic. Consequently, quantity of auto-doping from the substrate to the epitaxial layer during epitaxial growing is suppressed, and an epitaxial wafer having excellent resistance distribution and film thickness distribution can be obtained.
Description
本発明は、シリコン単結晶基板上にシリコン単結晶をエピタキシャル成長させて、エピタキシャル層を積層するシリコンエピタキシャルウェーハの製造方法に関する。
The present invention relates to a method for manufacturing a silicon epitaxial wafer in which a silicon single crystal is epitaxially grown on a silicon single crystal substrate and an epitaxial layer is laminated.
シリコンエピタキシャルウェーハ(以下単に「エピタキシャルウェーハ」と称す)は、例えば以下の通りにして製造される。
A silicon epitaxial wafer (hereinafter simply referred to as “epitaxial wafer”) is manufactured, for example, as follows.
すなわち、シリコン単結晶基板を気相成長装置の反応容器内に載置し、水素ガスを流した状態で、1000℃~1200℃まで反応容器内を昇温する(昇温工程)。反応容器内の温度が1000℃以上になると、基板表面に形成されている自然酸化膜(SiO2:Silicon Dioxide)が除去される。この状態で、トリクロロシラン(SiHCl3:Trichlorosilane)等のシリコン原料ガス、ジボラン(B2H6:Diborane)あるいはホスフィン(PH3:Phosphine)、アルシン(AsH3:Arsine) 等のドーパントガスを、水素ガスとともにプロセスガスとして反応容器内に供給する。こうして基板の主表面にエピタキシャル層を気相成長させる(エピ成長工程)。
このようにしてエピタキシャル層を気相成長させた後に、シリコン原料ガスおよびドーパントガスの供給を停止し、水素雰囲気に保持したまま反応容器内の温度を降温させる(冷却工程)。 That is, a silicon single crystal substrate is placed in a reaction vessel of a vapor phase growth apparatus, and the temperature in the reaction vessel is raised to 1000 ° C. to 1200 ° C. in a state where hydrogen gas is allowed to flow (temperature raising step). When the temperature in the reaction vessel reaches 1000 ° C. or higher, the natural oxide film (SiO 2 : Silicon Dioxide) formed on the substrate surface is removed. In this state, a silicon source gas such as trichlorosilane (SiHCl 3 : Trichlorosilane), a dopant gas such as diborane (B 2 H 6 : Diborane), phosphine (PH 3 : Phosphine), arsine (AsH 3 : Arsine), or the like is used. It is supplied into the reaction vessel as a process gas together with the gas. In this way, the epitaxial layer is vapor-phase grown on the main surface of the substrate (epi growth process).
After vapor phase growth of the epitaxial layer in this way, the supply of the silicon source gas and the dopant gas is stopped, and the temperature in the reaction vessel is lowered while maintaining the hydrogen atmosphere (cooling step).
このようにしてエピタキシャル層を気相成長させた後に、シリコン原料ガスおよびドーパントガスの供給を停止し、水素雰囲気に保持したまま反応容器内の温度を降温させる(冷却工程)。 That is, a silicon single crystal substrate is placed in a reaction vessel of a vapor phase growth apparatus, and the temperature in the reaction vessel is raised to 1000 ° C. to 1200 ° C. in a state where hydrogen gas is allowed to flow (temperature raising step). When the temperature in the reaction vessel reaches 1000 ° C. or higher, the natural oxide film (SiO 2 : Silicon Dioxide) formed on the substrate surface is removed. In this state, a silicon source gas such as trichlorosilane (SiHCl 3 : Trichlorosilane), a dopant gas such as diborane (B 2 H 6 : Diborane), phosphine (PH 3 : Phosphine), arsine (AsH 3 : Arsine), or the like is used. It is supplied into the reaction vessel as a process gas together with the gas. In this way, the epitaxial layer is vapor-phase grown on the main surface of the substrate (epi growth process).
After vapor phase growth of the epitaxial layer in this way, the supply of the silicon source gas and the dopant gas is stopped, and the temperature in the reaction vessel is lowered while maintaining the hydrogen atmosphere (cooling step).
このようにして製造されたエピタキシャルウェーハに対する品質について、エピタキシャル層の膜厚と抵抗率のウェーハ面内の均一性(以下「膜厚分布」と「抵抗分布」と称す)の向上がデバイスメーカーから要求されている。この中で抵抗分布についてのタイト化の要求が強い。
Regarding the quality of epitaxial wafers manufactured in this way, device manufacturers are required to improve the uniformity of the film thickness and resistivity of the epitaxial layer within the wafer surface (hereinafter referred to as “film thickness distribution” and “resistance distribution”). Has been. Among these, there is a strong demand for tightening the resistance distribution.
ところで、上述の通りにエピタキシャルウェーハを製造する過程の内、エピ成長工程では(1)成長温度、(2)シリコン原料ガス供給量、(3)反応圧力の3要素が重要であり、意図的に調整することができる。これら3要素がエピタキシャルウェーハの面内で均一であれば膜厚分布、抵抗分布が最良になる。
しかし、上記以外に抵抗分布に関する重要な、意図的に変える事が出来ない要素として、基板から発生する(4)アウトガスがある。抵抗分布とアウトガスの関係について以下に説明をする。 By the way, in the process of manufacturing an epitaxial wafer as described above, three elements of (1) growth temperature, (2) silicon source gas supply amount, and (3) reaction pressure are important in the epitaxial growth process. Can be adjusted. If these three elements are uniform in the plane of the epitaxial wafer, the film thickness distribution and resistance distribution are the best.
However, in addition to the above, an important factor regarding the resistance distribution that cannot be changed intentionally is (4) outgas generated from the substrate. The relationship between resistance distribution and outgas will be described below.
しかし、上記以外に抵抗分布に関する重要な、意図的に変える事が出来ない要素として、基板から発生する(4)アウトガスがある。抵抗分布とアウトガスの関係について以下に説明をする。 By the way, in the process of manufacturing an epitaxial wafer as described above, three elements of (1) growth temperature, (2) silicon source gas supply amount, and (3) reaction pressure are important in the epitaxial growth process. Can be adjusted. If these three elements are uniform in the plane of the epitaxial wafer, the film thickness distribution and resistance distribution are the best.
However, in addition to the above, an important factor regarding the resistance distribution that cannot be changed intentionally is (4) outgas generated from the substrate. The relationship between resistance distribution and outgas will be described below.
エピ成長工程では、1000℃以上の高い温度で基板がアニールされる為、基板よりドーパントを含むアウトガスが発生する。アウトガスは特に基板裏面から発生し、表面側に回り込む。表面での気相成長はプロセスガスによって行われているが、基板裏面から回り込んできたアウトガスがプロセスガスに混ざり、成長中のエピタキシャル層に取り込まれる(今後、「オートドープ」と称す)。
従って、製造されたエピタキシャルウェーハの中心部分とエッジ部とで取り込まれたドーパント量に違いが生じ、このようなオートドープは、アウトガスが多くなる低抵抗(概ね10.0mΩ・cm以下)の基板を用いた場合に影響が顕著になる。 In the epi-growth process, the substrate is annealed at a high temperature of 1000 ° C. or higher, so outgas containing dopant is generated from the substrate. Outgas is generated particularly from the back surface of the substrate and goes around to the front surface side. Vapor phase growth on the surface is performed by a process gas, but the outgas that has entered from the back of the substrate is mixed with the process gas and taken into the growing epitaxial layer (hereinafter referred to as “auto-dope”).
Therefore, there is a difference in the amount of dopant taken in between the center portion and the edge portion of the manufactured epitaxial wafer, and such auto-doping is a low-resistance (approximately 10.0 mΩ · cm or less) substrate that increases outgassing. When used, the effect becomes significant.
従って、製造されたエピタキシャルウェーハの中心部分とエッジ部とで取り込まれたドーパント量に違いが生じ、このようなオートドープは、アウトガスが多くなる低抵抗(概ね10.0mΩ・cm以下)の基板を用いた場合に影響が顕著になる。 In the epi-growth process, the substrate is annealed at a high temperature of 1000 ° C. or higher, so outgas containing dopant is generated from the substrate. Outgas is generated particularly from the back surface of the substrate and goes around to the front surface side. Vapor phase growth on the surface is performed by a process gas, but the outgas that has entered from the back of the substrate is mixed with the process gas and taken into the growing epitaxial layer (hereinafter referred to as “auto-dope”).
Therefore, there is a difference in the amount of dopant taken in between the center portion and the edge portion of the manufactured epitaxial wafer, and such auto-doping is a low-resistance (approximately 10.0 mΩ · cm or less) substrate that increases outgassing. When used, the effect becomes significant.
このようなオートドープを低減させるために、従来において、処理炉内のガス流速を2m/分以上、あるいはガス置換回数を3回/分以上の層流のキャリアガスを流下させる方法(特許文献1)等が取られてきたが、オートドープ量を大幅に低減させることは非常に困難であった。
In order to reduce such auto-doping, conventionally, a laminar carrier gas having a gas flow rate of 2 m / min or more in the processing furnace or a gas replacement frequency of 3 times / min or more is flowed down (Patent Document 1). However, it has been very difficult to significantly reduce the amount of autodope.
また、低耐圧P-MOSデバイス用途に、シリコン単結晶基板を非常に低抵抗率にしたエピタキシャルウェーハの要求が高まっている。中でも赤リンを多量にドープしたCZ結晶をエピタキシャル基板にした、N/N+++(5×1019atoms/cm3程度)エピタキシャルウェーハがこれからの主流として注目されている。
しかし、リンはSi中での拡散係数が高い為、エピ成長工程での熱処理で簡単に拡散してしまい、裏面からのオートドープによってエピタキシャル層の抵抗率低下や遷移領域のプロファイルにダレが起きやすいという問題があった。 In addition, for low voltage P-MOS device applications, there is an increasing demand for an epitaxial wafer having a very low resistivity silicon single crystal substrate. In particular, N / N ++++ (about 5 × 10 19 atoms / cm 3 ) epitaxial wafers using CZ crystals doped with a large amount of red phosphorus as an epitaxial substrate have attracted attention as a mainstream in the future.
However, since phosphorus has a high diffusion coefficient in Si, it is easily diffused by heat treatment in the epi-growth process, and auto-doping from the back surface tends to cause a decrease in the resistivity of the epitaxial layer and a transition region profile. There was a problem.
しかし、リンはSi中での拡散係数が高い為、エピ成長工程での熱処理で簡単に拡散してしまい、裏面からのオートドープによってエピタキシャル層の抵抗率低下や遷移領域のプロファイルにダレが起きやすいという問題があった。 In addition, for low voltage P-MOS device applications, there is an increasing demand for an epitaxial wafer having a very low resistivity silicon single crystal substrate. In particular, N / N ++++ (about 5 × 10 19 atoms / cm 3 ) epitaxial wafers using CZ crystals doped with a large amount of red phosphorus as an epitaxial substrate have attracted attention as a mainstream in the future.
However, since phosphorus has a high diffusion coefficient in Si, it is easily diffused by heat treatment in the epi-growth process, and auto-doping from the back surface tends to cause a decrease in the resistivity of the epitaxial layer and a transition region profile. There was a problem.
そこで、本発明はこのような問題点に鑑みなされたもので、エピタキシャル成長中におけるシリコン単結晶基板からエピタキシャル層へのオートドープ量を抑制し、抵抗分布の良好なエピタキシャルウェーハを得ることができるシリコンエピタキシャルウェーハの製造方法を提供することを目的とする。
Therefore, the present invention has been made in view of such problems, and silicon epitaxial that can suppress an autodoping amount from a silicon single crystal substrate to an epitaxial layer during epitaxial growth and can obtain an epitaxial wafer having a good resistance distribution. An object is to provide a method for manufacturing a wafer.
上記課題を解決するため、本発明では、シリコン単結晶基板上にシリコン単結晶をエピタキシャル成長させて、エピタキシャル層を積層するシリコンエピタキシャルウェーハの製造方法において、抵抗率が0.5mΩ・cm以上10.0mΩ・cm以下であり、リンまたはヒ素がドープされている前記シリコン単結晶基板上に、成長速度を3μm/分以上15μm/分以下として、抵抗率が0.5Ω・cm以上2000Ω・cm以下である前記エピタキシャル層を成長させることを特徴とするシリコンエピタキシャルウェーハの製造方法を提供する。
In order to solve the above problems, in the present invention, in a method for manufacturing a silicon epitaxial wafer in which a silicon single crystal is epitaxially grown on a silicon single crystal substrate and an epitaxial layer is laminated, the resistivity is 0.5 mΩ · cm or more and 10.0 mΩ. The resistivity is 0.5 Ω · cm or more and 2000 Ω · cm or less on the silicon single crystal substrate doped with phosphorus or arsenic at a growth rate of 3 μm / min or more and 15 μm / min or less. A method for producing a silicon epitaxial wafer is provided, wherein the epitaxial layer is grown.
このようなシリコンエピタキシャルウェーハの製造方法であれば、赤リンをドープした基板やヒ素をドープした基板など非常に低抵抗であり、オートドープの影響を大きく受けやすい基板を用いた場合であっても、その影響を最小限に抑えることができ、抵抗分布の良好なエピタキシャルウェーハを製造することができる。さらに、エピタキシャル層の成長速度を3μm/分以上の高速度としているため、生産性及び歩留まりの向上を図ることができる。また、成長速度を15μm/分以下とすることで、エピタキシャル成長を阻害するHClガスがシリコン原料ガスと水素ガスの反応により発生することを抑制でき、安定したエピタキシャル成長ができる。
また、このようにシリコン単結晶基板の抵抗率が0.5mΩ・cm以上10.0mΩ・cm以下であり、その上に形成されたエピタキシャル層の抵抗率が0.5Ω・cm以上2000Ω・cm以下であるようなエピタキシャルウェーハであれば、特にオートドープによる影響を受けやすいため、本発明の製造方法が好適である。 With such a method of manufacturing a silicon epitaxial wafer, even if a substrate having a very low resistance, such as a substrate doped with red phosphorus or a substrate doped with arsenic, is easily affected by autodoping. The influence can be suppressed to the minimum, and an epitaxial wafer having a good resistance distribution can be manufactured. Furthermore, since the growth rate of the epitaxial layer is set to a high rate of 3 μm / min or more, productivity and yield can be improved. Moreover, by setting the growth rate to 15 μm / min or less, it is possible to suppress generation of HCl gas that inhibits epitaxial growth due to the reaction between the silicon source gas and hydrogen gas, and stable epitaxial growth can be achieved.
Further, the resistivity of the silicon single crystal substrate is 0.5 mΩ · cm to 10.0 mΩ · cm, and the resistivity of the epitaxial layer formed thereon is 0.5 Ω · cm to 2000 Ω · cm. If it is such an epitaxial wafer, since it is easy to be influenced especially by auto dope, the manufacturing method of this invention is suitable.
また、このようにシリコン単結晶基板の抵抗率が0.5mΩ・cm以上10.0mΩ・cm以下であり、その上に形成されたエピタキシャル層の抵抗率が0.5Ω・cm以上2000Ω・cm以下であるようなエピタキシャルウェーハであれば、特にオートドープによる影響を受けやすいため、本発明の製造方法が好適である。 With such a method of manufacturing a silicon epitaxial wafer, even if a substrate having a very low resistance, such as a substrate doped with red phosphorus or a substrate doped with arsenic, is easily affected by autodoping. The influence can be suppressed to the minimum, and an epitaxial wafer having a good resistance distribution can be manufactured. Furthermore, since the growth rate of the epitaxial layer is set to a high rate of 3 μm / min or more, productivity and yield can be improved. Moreover, by setting the growth rate to 15 μm / min or less, it is possible to suppress generation of HCl gas that inhibits epitaxial growth due to the reaction between the silicon source gas and hydrogen gas, and stable epitaxial growth can be achieved.
Further, the resistivity of the silicon single crystal substrate is 0.5 mΩ · cm to 10.0 mΩ · cm, and the resistivity of the epitaxial layer formed thereon is 0.5 Ω · cm to 2000 Ω · cm. If it is such an epitaxial wafer, since it is easy to be influenced especially by auto dope, the manufacturing method of this invention is suitable.
またこのとき、前記エピタキシャル成長を行う際の成長温度を、1000℃以上とすることが好ましい。
Further, at this time, it is preferable that the growth temperature at the time of the epitaxial growth is 1000 ° C. or higher.
このような成長温度であれば、シリコン単結晶基板上の自然酸化膜を確実に除去することができ、シリコン単結晶基板上に膜厚分布のより良好なエピタキシャルウェーハを得ることができる。
With such a growth temperature, the natural oxide film on the silicon single crystal substrate can be reliably removed, and an epitaxial wafer with a better film thickness distribution can be obtained on the silicon single crystal substrate.
またこのとき、前記エピタキシャル層の成長速度を、5μm/分以上15μm/分以下とすることが好ましい。
At this time, the growth rate of the epitaxial layer is preferably 5 μm / min or more and 15 μm / min or less.
このような成長速度であれば、より効果的にオートドープを抑制することができ、抵抗分布及び膜厚分布のより良好なエピタキシャルウェーハを安定して得ることができる。
With such a growth rate, autodoping can be more effectively suppressed, and an epitaxial wafer with better resistance distribution and film thickness distribution can be stably obtained.
またこのとき、エピタキシャル成長中における、前記シリコン単結晶基板からエピタキシャル層へのオートドープ量と、前記エピタキシャル層の成長速度との相関関係を予め求め、該相関から前記エピタキシャル層の成長速度を決定することができる。
Also, at this time, during the epitaxial growth, a correlation between the amount of auto-doping from the silicon single crystal substrate to the epitaxial layer and the growth rate of the epitaxial layer is obtained in advance, and the growth rate of the epitaxial layer is determined from the correlation. Can do.
このようにすれば、エピタキシャルウェーハの中央部及びエッジ部の抵抗分布を、より効率良く均一にできる成長速度でエピタキシャル成長を行うことができるため、必要以上にシリコン原料ガスやキャリアガスを流入させたり、炉内温度を上げ過ぎてしまったりすることを防止でき、抵抗分布のより良好なエピタキシャルウェーハを確実に製造しつつ、さらにコストダウンすることができる。
In this way, since the epitaxial growth can be performed at a growth rate capable of making the resistance distribution at the center and edge portion of the epitaxial wafer more uniform and more efficient, silicon source gas or carrier gas is allowed to flow more than necessary, It is possible to prevent the temperature in the furnace from being raised excessively, and it is possible to further reduce the cost while reliably manufacturing an epitaxial wafer having a better resistance distribution.
以上説明したように、本発明によれば、エピタキシャル成長中のオートドープを効果的に抑制することができ、これによって抵抗分布の良好なエピタキシャルウェーハを製造することができる。
また、エピタキシャル層の成長速度を高速度としてエピタキシャル成長を行うため、生産性及び歩留まりを向上させることができる。 As described above, according to the present invention, autodoping during epitaxial growth can be effectively suppressed, and thus an epitaxial wafer having a good resistance distribution can be manufactured.
In addition, since epitaxial growth is performed at a high growth rate of the epitaxial layer, productivity and yield can be improved.
また、エピタキシャル層の成長速度を高速度としてエピタキシャル成長を行うため、生産性及び歩留まりを向上させることができる。 As described above, according to the present invention, autodoping during epitaxial growth can be effectively suppressed, and thus an epitaxial wafer having a good resistance distribution can be manufactured.
In addition, since epitaxial growth is performed at a high growth rate of the epitaxial layer, productivity and yield can be improved.
以下、図4のフローチャートを参照して、本発明の実施形態であるシリコンエピタキシャルウェーハの製造方法を説明するが、本発明はこれに限定されるものではない。図4は、本発明のシリコンエピタキシャルウェーハの製造方法の一例のフローチャートを示した図である。
ここでは、エピタキシャル層の成長温度を変化させずにシリコン原料ガスを増加させて高速成長させる場合について述べるが、もちろんシリコン原料ガスの量は変化させずに成長温度を上げて成長させても良いし、シリコン原料ガスを増加させた上でさらに成長温度を上げても良い。 Hereinafter, although the manufacturing method of the silicon epitaxial wafer which is embodiment of this invention is demonstrated with reference to the flowchart of FIG. 4, this invention is not limited to this. FIG. 4 is a view showing a flowchart of an example of the method for producing a silicon epitaxial wafer of the present invention.
Here, the case where the silicon source gas is increased without changing the growth temperature of the epitaxial layer for high-speed growth will be described. Of course, the growth may be performed at a higher growth temperature without changing the amount of the silicon source gas. The growth temperature may be further increased after increasing the silicon source gas.
ここでは、エピタキシャル層の成長温度を変化させずにシリコン原料ガスを増加させて高速成長させる場合について述べるが、もちろんシリコン原料ガスの量は変化させずに成長温度を上げて成長させても良いし、シリコン原料ガスを増加させた上でさらに成長温度を上げても良い。 Hereinafter, although the manufacturing method of the silicon epitaxial wafer which is embodiment of this invention is demonstrated with reference to the flowchart of FIG. 4, this invention is not limited to this. FIG. 4 is a view showing a flowchart of an example of the method for producing a silicon epitaxial wafer of the present invention.
Here, the case where the silicon source gas is increased without changing the growth temperature of the epitaxial layer for high-speed growth will be described. Of course, the growth may be performed at a higher growth temperature without changing the amount of the silicon source gas. The growth temperature may be further increased after increasing the silicon source gas.
先ず、気相成長装置の反応容器内に備えられたサセプタ上に搬送装置を用いて、抵抗率が0.5mΩ・cm以上10.0mΩ・cm以下で、リンがドープされたシリコン単結晶基板を載置する(仕込み工程)。このとき、シリコン単結晶基板は赤リンをドープしたCZ結晶より製造されたものが好適である。また、リンの代わりにヒ素をドープしても良い。
次いで、反応容器内に水素ガスを流した状態で、反応容器内の温度を、エピタキシャル層を気相成長させるための成長温度まで昇温する(昇温工程)。この成長温度は、基板表面の自然酸化膜を水素で確実に除去できる1000℃以上に設定する。この場合、上限は特に限定されないが、1300℃以下とすれば、スリップの発生や汚染の発生が抑止できる。 First, using a transfer device on a susceptor provided in a reaction vessel of a vapor phase growth apparatus, a silicon single crystal substrate doped with phosphorus having a resistivity of 0.5 mΩ · cm to 10.0 mΩ · cm is used. Place (preparation process). At this time, the silicon single crystal substrate is preferably manufactured from a CZ crystal doped with red phosphorus. Further, arsenic may be doped instead of phosphorus.
Next, with the hydrogen gas flowing in the reaction vessel, the temperature in the reaction vessel is raised to a growth temperature for vapor-phase growth of the epitaxial layer (temperature raising step). This growth temperature is set to 1000 ° C. or higher at which the natural oxide film on the substrate surface can be reliably removed with hydrogen. In this case, the upper limit is not particularly limited, but if it is 1300 ° C. or lower, the occurrence of slip and the occurrence of contamination can be suppressed.
次いで、反応容器内に水素ガスを流した状態で、反応容器内の温度を、エピタキシャル層を気相成長させるための成長温度まで昇温する(昇温工程)。この成長温度は、基板表面の自然酸化膜を水素で確実に除去できる1000℃以上に設定する。この場合、上限は特に限定されないが、1300℃以下とすれば、スリップの発生や汚染の発生が抑止できる。 First, using a transfer device on a susceptor provided in a reaction vessel of a vapor phase growth apparatus, a silicon single crystal substrate doped with phosphorus having a resistivity of 0.5 mΩ · cm to 10.0 mΩ · cm is used. Place (preparation process). At this time, the silicon single crystal substrate is preferably manufactured from a CZ crystal doped with red phosphorus. Further, arsenic may be doped instead of phosphorus.
Next, with the hydrogen gas flowing in the reaction vessel, the temperature in the reaction vessel is raised to a growth temperature for vapor-phase growth of the epitaxial layer (temperature raising step). This growth temperature is set to 1000 ° C. or higher at which the natural oxide film on the substrate surface can be reliably removed with hydrogen. In this case, the upper limit is not particularly limited, but if it is 1300 ° C. or lower, the occurrence of slip and the occurrence of contamination can be suppressed.
次いで、反応容器内を成長温度に保持したままで、水素ガスとともにシリコン原料ガスおよびドーパントガスをそれぞれ所定流量で供給し、成長速度を3μm/分以上15μm/分以下、より好ましくは5μm/分以上15μm/分以下、さらに好ましくは6μm/分以上15μm/分以下で、所定膜厚となるまで抵抗率が0.5Ω・cm以上2000Ω・cm以下となるエピタキシャル層を成長させる(エピ成長工程)。通常の成長速度から高速成長にする場合、成長温度によって異なるが、シリコン原料ガスを通常に比べ、1.5倍~4.0倍に増加させる。
本発明においては、1000℃以上の高温であっても、3μm/分以上15μm/分以下の成長速度でエピタキシャル層を高速成長させるため、基板にドープされているドーパントのオートドープ量を抑制し、抵抗分布及び膜厚分布の良好なエピタキシャル層を安定して成長させることができる。 Next, while keeping the inside of the reaction vessel at the growth temperature, the silicon raw material gas and the dopant gas are supplied at a predetermined flow rate together with the hydrogen gas, and the growth rate is 3 μm / min or more and 15 μm / min or less, more preferably 5 μm / min or more. An epitaxial layer having a resistivity of 0.5 Ω · cm to 2000 Ω · cm is grown at 15 μm / min or less, more preferably 6 μm / min or more and 15 μm / min or less until the film thickness reaches a predetermined thickness (epi growth process). When changing from a normal growth rate to a high-speed growth, although depending on the growth temperature, the silicon source gas is increased 1.5 times to 4.0 times compared to the normal growth rate.
In the present invention, the epitaxial layer is grown at a high growth rate of 3 μm / min to 15 μm / min even at a high temperature of 1000 ° C. or higher, so that the amount of dopants doped in the substrate is suppressed, An epitaxial layer having a good resistance distribution and film thickness distribution can be stably grown.
本発明においては、1000℃以上の高温であっても、3μm/分以上15μm/分以下の成長速度でエピタキシャル層を高速成長させるため、基板にドープされているドーパントのオートドープ量を抑制し、抵抗分布及び膜厚分布の良好なエピタキシャル層を安定して成長させることができる。 Next, while keeping the inside of the reaction vessel at the growth temperature, the silicon raw material gas and the dopant gas are supplied at a predetermined flow rate together with the hydrogen gas, and the growth rate is 3 μm / min or more and 15 μm / min or less, more preferably 5 μm / min or more. An epitaxial layer having a resistivity of 0.5 Ω · cm to 2000 Ω · cm is grown at 15 μm / min or less, more preferably 6 μm / min or more and 15 μm / min or less until the film thickness reaches a predetermined thickness (epi growth process). When changing from a normal growth rate to a high-speed growth, although depending on the growth temperature, the silicon source gas is increased 1.5 times to 4.0 times compared to the normal growth rate.
In the present invention, the epitaxial layer is grown at a high growth rate of 3 μm / min to 15 μm / min even at a high temperature of 1000 ° C. or higher, so that the amount of dopants doped in the substrate is suppressed, An epitaxial layer having a good resistance distribution and film thickness distribution can be stably grown.
また、ここで基板からエピタキシャル層へのオートドープ量と、エピタキシャル層の成長速度との相関関係を予め求めておいて、該相関を基に成長速度を決定しても良い。
例えば、抵抗率が2.0mΩ・cmであって、リンがドープされたシリコン単結晶基板上に、成長温度を1100℃として、シリコン原料ガスであるトリクロロシランガスの流量を変化させることによって、成長速度を1~9μm/分の間で変化させてエピタキシャル層を積層した。このときに得られたエピタキシャルウェーハのオートドープ量をそれぞれ測定した結果、オートドープ量と成長速度との間に図1に示すような相関が得られた。 Further, here, a correlation between the amount of autodope from the substrate to the epitaxial layer and the growth rate of the epitaxial layer may be obtained in advance, and the growth rate may be determined based on the correlation.
For example, on a silicon single crystal substrate having a resistivity of 2.0 mΩ · cm and doped with phosphorus, the growth temperature is set to 1100 ° C., and the growth rate is changed by changing the flow rate of trichlorosilane gas, which is a silicon source gas. The epitaxial layer was stacked while changing the thickness between 1 and 9 μm / min. As a result of measuring the autodoping amount of the epitaxial wafer obtained at this time, a correlation as shown in FIG. 1 was obtained between the autodoping amount and the growth rate.
例えば、抵抗率が2.0mΩ・cmであって、リンがドープされたシリコン単結晶基板上に、成長温度を1100℃として、シリコン原料ガスであるトリクロロシランガスの流量を変化させることによって、成長速度を1~9μm/分の間で変化させてエピタキシャル層を積層した。このときに得られたエピタキシャルウェーハのオートドープ量をそれぞれ測定した結果、オートドープ量と成長速度との間に図1に示すような相関が得られた。 Further, here, a correlation between the amount of autodope from the substrate to the epitaxial layer and the growth rate of the epitaxial layer may be obtained in advance, and the growth rate may be determined based on the correlation.
For example, on a silicon single crystal substrate having a resistivity of 2.0 mΩ · cm and doped with phosphorus, the growth temperature is set to 1100 ° C., and the growth rate is changed by changing the flow rate of trichlorosilane gas, which is a silicon source gas. The epitaxial layer was stacked while changing the thickness between 1 and 9 μm / min. As a result of measuring the autodoping amount of the epitaxial wafer obtained at this time, a correlation as shown in FIG. 1 was obtained between the autodoping amount and the growth rate.
この相関を基に成長速度を決定する場合、例えば成長速度が3μm/分以上とすれば、2μm/分以下の通常の成長速度でエピタキシャル成長を行った場合と比べ、オートドープ量が抑制されることがわかる。また5μm/分以上とすれば、より効果的にオートドープ量が抑制され、さらに6μm/分以上とすれば、オートドープがほとんど生じず、エピタキシャルウェーハのエッジ部と中心部とでは抵抗率にほとんど差が無くなり、抵抗分布及び膜厚分布がほぼ均一化されることがわかる。
When determining the growth rate based on this correlation, for example, if the growth rate is 3 μm / min or more, the amount of auto-doping is suppressed compared to the case where epitaxial growth is performed at a normal growth rate of 2 μm / min or less. I understand. Further, if it is 5 μm / min or more, the amount of auto-doping is suppressed more effectively, and if it is 6 μm / min or more, auto-doping hardly occurs, and the resistivity at the edge portion and the center portion of the epitaxial wafer is hardly increased. It can be seen that the difference disappears and the resistance distribution and the film thickness distribution are almost uniform.
次いで、反応容器内の温度を下降させて取り出し温度までエピタキシャルウェーハを冷却する(冷却工程)。この冷却工程では、800℃から400℃程度の間で、水素雰囲気から窒素雰囲気へと切り換えられる。そして、窒素雰囲気のままで取り出し温度に至ったら、気相成長装置からエピタキシャルウェーハを取り出す(取り出し工程)。
Next, the temperature in the reaction vessel is lowered to cool the epitaxial wafer to the take-out temperature (cooling process). In this cooling step, the hydrogen atmosphere is switched to the nitrogen atmosphere between about 800 ° C. and 400 ° C. And if it takes out temperature in nitrogen atmosphere, an epitaxial wafer will be taken out from a vapor phase growth apparatus (takeout process).
次いで、取り出したエピタキシャルウェーハに対し、適宜RCA洗浄等の洗浄を行う(洗浄工程)。この洗浄工程における洗浄法は、典型的なRCA洗浄の他、薬液の濃度や種類を通常行われる範囲で変更したものを用いることもできる。
Next, the extracted epitaxial wafer is appropriately cleaned such as RCA cleaning (cleaning process). As a cleaning method in this cleaning step, in addition to a typical RCA cleaning, a method in which the concentration and type of a chemical solution are changed within a normal range can be used.
そして、パーティクルカウンタにより、エピタキシャルウェーハ表面に生成するパーティクル状の異物の有無を確認し(パーティクルカウンタ計測)、その後製品となるエピタキシャルウェーハを選別する(選別)。
Then, the presence or absence of particle-like foreign matter generated on the surface of the epitaxial wafer is confirmed by a particle counter (particle counter measurement), and then an epitaxial wafer as a product is sorted (sorting).
以下、実施例及び比較例を示して本発明をより具体的に説明するが、本発明はこれに限定されるものではない。
Hereinafter, the present invention will be described more specifically with reference to examples and comparative examples, but the present invention is not limited thereto.
(実施例1)
抵抗率が1.0mΩ・cmであって、リンがドープされた直径200mmのシリコン単結晶基板上に、抵抗率1.5Ω・cm、膜厚1μmのエピタキシャル層を、成長温度1100℃、成長速度を6μm/分として高速成長させ、エピタキシャルウェーハを製造した。その後、製造したエピタキシャルウェーハの抵抗率を径方向に測定した。このときの結果を図2に示す。 Example 1
An epitaxial layer having a resistivity of 1.5 Ω · cm and a thickness of 1 μm on a silicon single crystal substrate having a resistivity of 1.0 mΩ · cm and doped with phosphorus and having a diameter of 200 mm is grown at a growth temperature of 1100 ° C. and a growth rate. Was grown at a high speed of 6 μm / min to produce an epitaxial wafer. Thereafter, the resistivity of the manufactured epitaxial wafer was measured in the radial direction. The result at this time is shown in FIG.
抵抗率が1.0mΩ・cmであって、リンがドープされた直径200mmのシリコン単結晶基板上に、抵抗率1.5Ω・cm、膜厚1μmのエピタキシャル層を、成長温度1100℃、成長速度を6μm/分として高速成長させ、エピタキシャルウェーハを製造した。その後、製造したエピタキシャルウェーハの抵抗率を径方向に測定した。このときの結果を図2に示す。 Example 1
An epitaxial layer having a resistivity of 1.5 Ω · cm and a thickness of 1 μm on a silicon single crystal substrate having a resistivity of 1.0 mΩ · cm and doped with phosphorus and having a diameter of 200 mm is grown at a growth temperature of 1100 ° C. and a growth rate. Was grown at a high speed of 6 μm / min to produce an epitaxial wafer. Thereafter, the resistivity of the manufactured epitaxial wafer was measured in the radial direction. The result at this time is shown in FIG.
(実施例2)
抵抗率が2.0mΩ・cmであって、ヒ素がドープされた直径200mmのシリコン単結晶基板上に、抵抗率2.0Ω・cm、膜厚1μmのエピタキシャル層を、成長温度1100℃、成長速度を6μm/分として高速成長させ、エピタキシャルウェーハを製造した。その後、製造したエピタキシャルウェーハの抵抗率を径方向に測定した。このときの結果を図3に示す。 (Example 2)
An epitaxial layer having a resistivity of 2.0 Ω · cm and a thickness of 1 μm on a silicon single crystal substrate having a resistivity of 2.0 mΩ · cm and doped with arsenic and having a diameter of 200 mm is grown at a growth temperature of 1100 ° C. and a growth rate. Was grown at a high speed of 6 μm / min to produce an epitaxial wafer. Thereafter, the resistivity of the manufactured epitaxial wafer was measured in the radial direction. The result at this time is shown in FIG.
抵抗率が2.0mΩ・cmであって、ヒ素がドープされた直径200mmのシリコン単結晶基板上に、抵抗率2.0Ω・cm、膜厚1μmのエピタキシャル層を、成長温度1100℃、成長速度を6μm/分として高速成長させ、エピタキシャルウェーハを製造した。その後、製造したエピタキシャルウェーハの抵抗率を径方向に測定した。このときの結果を図3に示す。 (Example 2)
An epitaxial layer having a resistivity of 2.0 Ω · cm and a thickness of 1 μm on a silicon single crystal substrate having a resistivity of 2.0 mΩ · cm and doped with arsenic and having a diameter of 200 mm is grown at a growth temperature of 1100 ° C. and a growth rate. Was grown at a high speed of 6 μm / min to produce an epitaxial wafer. Thereafter, the resistivity of the manufactured epitaxial wafer was measured in the radial direction. The result at this time is shown in FIG.
(比較例1)
成長速度を2μm/分とすること以外は実施例1と同様にエピタキシャルウェーハを製造し、その後、製造したエピタキシャルウェーハの抵抗率を径方向に測定した。このときの結果を図2に合わせて示す。 (Comparative Example 1)
An epitaxial wafer was manufactured in the same manner as in Example 1 except that the growth rate was 2 μm / min, and then the resistivity of the manufactured epitaxial wafer was measured in the radial direction. The results at this time are also shown in FIG.
成長速度を2μm/分とすること以外は実施例1と同様にエピタキシャルウェーハを製造し、その後、製造したエピタキシャルウェーハの抵抗率を径方向に測定した。このときの結果を図2に合わせて示す。 (Comparative Example 1)
An epitaxial wafer was manufactured in the same manner as in Example 1 except that the growth rate was 2 μm / min, and then the resistivity of the manufactured epitaxial wafer was measured in the radial direction. The results at this time are also shown in FIG.
(比較例2)
成長速度を2μm/分とすること以外は実施例2と同様にエピタキシャルウェーハを製造し、その後、製造したエピタキシャルウェーハの抵抗率を径方向に測定した。このときの結果を図3に合わせて示す。 (Comparative Example 2)
An epitaxial wafer was manufactured in the same manner as in Example 2 except that the growth rate was 2 μm / min, and then the resistivity of the manufactured epitaxial wafer was measured in the radial direction. The results at this time are also shown in FIG.
成長速度を2μm/分とすること以外は実施例2と同様にエピタキシャルウェーハを製造し、その後、製造したエピタキシャルウェーハの抵抗率を径方向に測定した。このときの結果を図3に合わせて示す。 (Comparative Example 2)
An epitaxial wafer was manufactured in the same manner as in Example 2 except that the growth rate was 2 μm / min, and then the resistivity of the manufactured epitaxial wafer was measured in the radial direction. The results at this time are also shown in FIG.
比較例1及び比較例2に示した条件でエピタキシャル成長を行った場合、1000℃以上の高温状態で、低抵抗基板上に高抵抗のエピタキシャル層を2μm/分の通常の成長速度で形成するため、基板にドープされているリンまたはヒ素が拡散し、オートドープの影響を受けやすい。このため、比較例1及び比較例2では、製造されたエピタキシャルウェーハのエッジ部の抵抗率が極端に下がってしまっている。
しかし、本発明の製造方法を用いた実施例1及び実施例2では、6μm/分の成長速度でエピタキシャル層を高速成長させているため、発生するオートドープ量を抑制することができる。このため、製造されたエピタキシャルウェーハのエッジ部と中心部とで抵抗率がほぼ均一化されているのがわかる。 When epitaxial growth is performed under the conditions shown in Comparative Examples 1 and 2, in order to form a high resistance epitaxial layer on a low resistance substrate at a normal growth rate of 2 μm / min at a high temperature of 1000 ° C. or higher, Phosphorus or arsenic doped in the substrate diffuses and is susceptible to autodoping. For this reason, in the comparative example 1 and the comparative example 2, the resistivity of the edge part of the manufactured epitaxial wafer has fallen extremely.
However, in Example 1 and Example 2 using the manufacturing method of the present invention, since the epitaxial layer is grown at a high growth rate of 6 μm / min, the amount of autodope generated can be suppressed. For this reason, it can be seen that the resistivity is substantially uniform at the edge and the center of the manufactured epitaxial wafer.
しかし、本発明の製造方法を用いた実施例1及び実施例2では、6μm/分の成長速度でエピタキシャル層を高速成長させているため、発生するオートドープ量を抑制することができる。このため、製造されたエピタキシャルウェーハのエッジ部と中心部とで抵抗率がほぼ均一化されているのがわかる。 When epitaxial growth is performed under the conditions shown in Comparative Examples 1 and 2, in order to form a high resistance epitaxial layer on a low resistance substrate at a normal growth rate of 2 μm / min at a high temperature of 1000 ° C. or higher, Phosphorus or arsenic doped in the substrate diffuses and is susceptible to autodoping. For this reason, in the comparative example 1 and the comparative example 2, the resistivity of the edge part of the manufactured epitaxial wafer has fallen extremely.
However, in Example 1 and Example 2 using the manufacturing method of the present invention, since the epitaxial layer is grown at a high growth rate of 6 μm / min, the amount of autodope generated can be suppressed. For this reason, it can be seen that the resistivity is substantially uniform at the edge and the center of the manufactured epitaxial wafer.
なお、本発明は、上記実施形態に限定されるものではない。例えば、本発明でエピタキシャル層を気相成長させる気相成長装置は限定されず、縦型(パンケーキ型)、バレル型(シリンダ型)、枚葉式等の各種気相成長装置に適用可能である。上記実施形態は、例示であり、本発明の特許請求の範囲に記載された技術的思想と実質的に同一な構成を有し、同様な作用効果を奏するものは、いかなるものであっても本発明の技術的範囲に包含される。
Note that the present invention is not limited to the above embodiment. For example, the vapor phase growth apparatus for vapor growth of the epitaxial layer in the present invention is not limited, and can be applied to various vapor phase growth apparatuses such as a vertical type (pancake type), a barrel type (cylinder type), and a single wafer type. is there. The above-described embodiment is an exemplification, and the present invention has substantially the same configuration as the technical idea described in the claims of the present invention, and any device that exhibits the same function and effect is the present invention. It is included in the technical scope of the invention.
Claims (4)
- シリコン単結晶基板上にシリコン単結晶をエピタキシャル成長させて、エピタキシャル層を積層するシリコンエピタキシャルウェーハの製造方法において、抵抗率が0.5mΩ・cm以上10.0mΩ・cm以下であり、リンまたはヒ素がドープされている前記シリコン単結晶基板上に、成長速度を3μm/分以上15μm/分以下として、抵抗率が0.5Ω・cm以上2000Ω・cm以下である前記エピタキシャル層を成長させることを特徴とするシリコンエピタキシャルウェーハの製造方法。 In a method of manufacturing a silicon epitaxial wafer by epitaxially growing a silicon single crystal on a silicon single crystal substrate and laminating an epitaxial layer, the resistivity is 0.5 mΩ · cm to 10.0 mΩ · cm and doped with phosphorus or arsenic The epitaxial layer having a resistivity of 0.5 Ω · cm or more and 2000 Ω · cm or less is grown on the silicon single crystal substrate that has been grown at a growth rate of 3 μm / min to 15 μm / min. A method for producing a silicon epitaxial wafer.
- 前記エピタキシャル成長を行う際の成長温度を、1000℃以上とすることを特徴とする請求項1に記載のシリコンエピタキシャルウェーハの製造方法。 The method for producing a silicon epitaxial wafer according to claim 1, wherein a growth temperature at the time of performing the epitaxial growth is set to 1000 ° C. or higher.
- 前記エピタキシャル層の成長速度を、5μm/分以上15μm/分以下とすることを特徴とする請求項1または請求項2に記載のシリコンエピタキシャルウェーハの製造方法。 3. The method for producing a silicon epitaxial wafer according to claim 1, wherein a growth rate of the epitaxial layer is set to 5 μm / min or more and 15 μm / min or less.
- エピタキシャル成長中における、前記シリコン単結晶基板からエピタキシャル層へのオートドープ量と、前記エピタキシャル層の成長速度との相関関係を予め求め、該相関から前記エピタキシャル層の成長速度を決定することを特徴とする請求項1乃至請求項3のいずれか1項に記載のシリコンエピタキシャルウェーハの製造方法。 In the epitaxial growth, a correlation between the auto-doping amount from the silicon single crystal substrate to the epitaxial layer and the growth rate of the epitaxial layer is obtained in advance, and the growth rate of the epitaxial layer is determined from the correlation The manufacturing method of the silicon epitaxial wafer of any one of Claim 1 thru | or 3.
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