JP2000091237A - Manufacture of semiconductor wafer - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method of manufacturing a semiconductor wafer, which is capable of growing thin film of a semiconductor having homogeneous resistivity on a major surface of even a large-diameter semiconductor single-crystal substrate. SOLUTION: In the vapor growth of thin film 9 of a semiconductor on a semiconductor single-crystal substrate 6, semiconductor material gas and dopant gas are supplied from a central part in the width direction and from peripheral parts in the width direction of a reaction chamber 4, wherein the gas flow directions are in parallel and in the same direction with respect to the major surface of the semiconductor single-crystal substrate 6 which rotates in the reaction chamber 4. The supply of the dopant gas from the peripheral parts is limited only from an either one that yields the gas flow direction forward or reverse with respect to the direction of rotation of the semiconductor single crystal substrate 6.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a method for manufacturing a semiconductor wafer in which a semiconductor thin film having a uniform resistivity distribution is vapor-phase grown on a semiconductor single crystal substrate such as a silicon single crystal substrate.

[0002]

2. Description of the Related Art With the miniaturization of electronic devices, the use of semiconductor wafers formed by forming a silicon single crystal thin film on a silicon single crystal substrate is increasing, and uniformity of the resistivity of the silicon single crystal thin film is required. Is coming. The uniformity of the resistivity means that the resistivity is made uniform in the plane of the silicon single crystal thin film. In addition to the uniformity of the resistivity, a large diameter semiconductor wafer is required.
With the increase in diameter, a horizontal single-wafer-type vapor-phase growth apparatus is mainly used as an apparatus for growing a silicon single crystal thin film.

FIG. 3 and FIG. 4 schematically show the configuration of a generally used horizontal single-wafer type vapor phase growth apparatus 1 (hereinafter sometimes simply referred to as growth apparatus 1). FIG. 3 shows a longitudinal section of the growth apparatus 1, and FIG. 4 shows a transverse section thereof.

The growth apparatus 1 comprises a reaction vessel 4 made of transparent quartz glass and provided horizontally with a gas introduction port 2 and a single gas exhaust port 3, and a semiconductor arranged outside the reaction vessel 4. A heating source 5 for heating a single crystal substrate 6;
And a cooling means (not shown) for cooling the outer wall of the reaction vessel 4 and a susceptor 7 for the semiconductor single crystal substrate 6.

A gas inlet 2 introduces a source gas and a dopant gas together with hydrogen H ₂ as a carrier gas.
It comprises three horizontally arranged gas inlets 21, 22, 23. The reaction vessel 4 has a structure in which a susceptor 7 is disposed at the center bottom thereof. The gas introduction port 2 is provided at one end in the substantially longitudinal direction, and the gas exhaust port 3 is provided at the other end. Therefore, the flow of the gas introduced generally follows the longitudinal direction of the reaction vessel 4. The flow rate of each gas is individually and precisely controlled by a mass flow controller (MFC) as a gas condition controller.

The heating source 5 is constituted by, for example, an infrared lamp. By supplying a current to the infrared lamp, the temperature of the main surface of the semiconductor single crystal substrate 6 can be increased. The susceptor 7 is connected to a rotating device (not shown) via a rotating shaft 8, and can be rotated while the main surface of the semiconductor single crystal substrate 6 placed on the susceptor 7 is held horizontally.

In order to grow a semiconductor thin film 9 on a semiconductor single crystal substrate 6 in vapor phase, a mass flow controller (MFC)
Using hydrogen, a semiconductor source gas, and a dopant gas whose flow rates are precisely controlled by 50, 51, and 52 as process gases, a gas inlet 22 at the center in the width direction of the reaction vessel 4 through a common gas pipe 41. In addition, the gas is supplied from the gas introduction ports 21 and 23 at the peripheral portion in the width direction to the main surface of the semiconductor single crystal substrate 6 rotating around the rotation axis 8 in the reaction vessel 4 and in one direction. At this time, the gas inlets 21 and
Process gases having the same source gas concentration and the same dopant gas concentration are supplied from 2, 23.

[0008]

In the method of introducing a process gas as described above and vapor-phase growing a semiconductor thin film, when the diameter of the semiconductor single crystal substrate is 200 mm or less, a remarkable resistivity is not obtained. No uniformity problem occurred.
However, it has been found that when the diameter is larger than 200 mm, for example, when a large-diameter semiconductor wafer having a diameter of 300 mm is manufactured by the above-described conventional vapor deposition method, the distribution of the resistivity becomes significantly non-uniform.

In view of the above technical problems, the present invention provides a method of manufacturing a semiconductor wafer capable of vapor-phase growing a semiconductor thin film having a uniform resistivity on a large-diameter semiconductor single crystal substrate. The purpose is to do.

[0010]

According to the present invention, there is provided a method of manufacturing a semiconductor wafer, comprising the steps of: starting from a central portion in a width direction and a peripheral portion in a width direction of a reaction vessel; In a method of manufacturing a semiconductor wafer in which a semiconductor source gas and a dopant gas are supplied in parallel and in one direction to vapor-grow a semiconductor thin film on the semiconductor single crystal substrate, a dopant supplied from a peripheral portion in a width direction of the reaction vessel It is characterized in that the gas is supplied only in one of the forward and reverse directions with respect to the rotation direction of the semiconductor single crystal substrate.

In the above method, a dopant gas supplied from a peripheral portion in a width direction of the reaction vessel is supplied in a forward direction with respect to a rotation direction of the semiconductor single crystal substrate in accordance with a resistivity or a resistivity distribution of the semiconductor thin film. Alternatively, it is preferable to change to the opposite direction. Preferably, the direction of rotation of the semiconductor single crystal substrate is changed according to the resistivity distribution of the semiconductor thin film. Further, the semiconductor single crystal substrate is preferably a silicon single crystal substrate, and the semiconductor thin film is preferably a silicon single crystal thin film.

Further, according to the method of manufacturing a semiconductor wafer of the present invention, it is preferable that a central portion and a peripheral portion in the width direction of the reaction vessel are parallel to one direction with respect to the main surface of the semiconductor single crystal substrate rotating in the reaction vessel. Supplying a semiconductor source gas and a dopant gas to vapor-grow a semiconductor thin film on the semiconductor single crystal substrate, wherein the semiconductor single crystal substrate is provided in accordance with a resistivity distribution of the semiconductor thin film. Is characterized in that the direction of rotation of is changed.

[0013]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 schematically shows a cross section of a horizontal single-wafer type vapor phase growth apparatus 1 according to this embodiment. In FIG. 1, the same components as those of the related art are denoted by the same reference numerals, and description thereof will be omitted. The longitudinal section of the growth apparatus 1 of the present embodiment has the same configuration as that of FIG.

As shown in FIG. 1, in the horizontal single-wafer type vapor phase growth apparatus 1 of this embodiment, three horizontally arranged gas inlets 21, 22 arranged in the width direction of the reaction vessel 4. 2
Process gas introduced from 3 is independently controlled. That is, the process gas introduced from the gas inlet 21 is supplied through the gas pipe 11, and the hydrogen is supplied to the mass flow controller (MFC) 30, the raw material gas is supplied to the mass flow controller (MFC) 31, and the dopant is supplied to the mass flow controller (MFC) 32. Is controlled by The process gas introduced from the gas inlet 22 is supplied to the gas pipe 12
And hydrogen is supplied to the mass flow controller (M
FC) 33, the source gas is a mass flow controller (MF)
C) 34, the dopant is a mass flow controller (MF)
C) Controlled by 35. The process gas introduced from the gas inlet 23 is supplied through the gas pipe 13, and hydrogen is controlled by a mass flow controller (MFC) 36, source gas is controlled by a mass flow controller (MFC) 37, and dopant is controlled by a mass flow controller (MFC) 38. Is done.

Thus, the three gas inlets 21, 22,
23 each have a dopant gas condition controller.
Mass flow controllers (MFC) 32, 35, 38
Connected and the flow rate and
And / or concentration is controlled with high precision. For this gas control
Controls such as shutting off, starting, and continuing the introduction of dopant gas.
Including Further, from the gas inlets 21, 22, and 23,
Is, for example, SiCl₄Gas, SiH
₂Cl₂Gas, SiHCl₃Gas, SiH₄Such as gas
A silicon-based gas is introduced. Also, as a dopant gas
Is, for example, diborane (B ₂H₆) Gas, phosphine
(PH₃) Gas or the like is used.

Using this apparatus, the resistivity distribution of the semiconductor thin film 9 to be vapor-phase grown on the semiconductor single crystal substrate 6 is adjusted by the combination of the respective mass flow controllers (MFC) 32, 35, and 38. That is, the resistivity distribution of the semiconductor thin film 9 is changed by adjusting the supply amount of the dopant gas from each of the mass flow controllers (MFCs) 32, 35, and 38, that is, the concentration of the dopant gas at each of the gas introduction ports 21, 22, and 23.

First, the dopant gas is supplied only from the mass flow controller (MFC) 35 to the gas inlet 22 (the center in the width direction of the reaction vessel 4) while the semiconductor single crystal substrate 6 is rotated clockwise by a rotating device (not shown). While growing, the semiconductor thin film 9 is vapor-phase grown. Then, as shown by a curve 1 in FIG. 2, the uniformity of the resistivity is good at the inner peripheral portion of the semiconductor single crystal substrate 6, while the resistivity at the outer peripheral portion gradually increases as approaching the outer peripheral portion. However, in this case, the magnitude of the gradient of the resistivity change differs depending on the target resistivity of the semiconductor thin film 9. That is, when growing a relatively low-resistance semiconductor thin film 9, the resistivity of the outer peripheral portion gradually increases, while when growing a relatively high-resistance semiconductor thin film 9, the resistivity of the outer peripheral portion sharply increases. It tends to rise.

Next, in the same condition as above, when the dopant gas is supplied only from the mass flow controller (MFC) 32 to the gas inlet 21 (left side peripheral portion of the reaction vessel 4 at the left side), vapor phase growth is performed. As shown by a curve 2 in FIG. 2, the resistivity of the semiconductor thin film 9 in the internal portion becomes substantially uniform.
However, the resistivity on the outer peripheral portion rapidly decreases as approaching the outer peripheral portion. This is because the gas inlet 21 introduces a gas in the forward direction with respect to the rotation direction of the semiconductor single crystal substrate 6. It is presumed that as a result of being supplied intensively to the portion, the resistivity tends to sharply decrease at the outer peripheral portion.

Further, in the same manner as described above, when a dopant gas is supplied only from the mass flow controller (MFC) 38 to the gas inlet 23 (the right side peripheral portion of the reaction vessel 4 in the width direction), vapor phase growth is performed. Like curve 3 of 2,
The resistivity of the semiconductor thin film 9 gradually decreases from the center of the semiconductor single crystal substrate 6 toward the outer periphery. This is because the gas inlet 23 introduces gas in the direction opposite to the rotation direction of the semiconductor single crystal substrate 6, and the flow of the introduced dopant gas is disturbed and spreads widely on the semiconductor single crystal substrate 6. It is presumed that they are distributed, and as a result, the resistivity distribution is greatly expanded, and thus tends to gradually decrease toward the outer peripheral portion.

Therefore, the dopant gas is supplied from the gas inlet 22 located at the center of the reactor 4 in the width direction, and the dopant gas is supplied from either the gas inlet 21 or 23 located at the peripheral portion of the reactor 4 in the width direction. Supply gas. That is, the dopant gas supplied from the peripheral portion in the width direction of the reaction container 4 is limited to one of the forward direction and the reverse direction with respect to the rotation direction of the semiconductor single crystal substrate 6.

By supplying the dopant gas from the gas inlet 22 and supplying the dopant gas from either the gas inlet 21 or 23, the curve 4 in FIG.
A uniform resistivity distribution can be obtained in a plane having an ideal resistivity distribution as shown in FIG. For example, a semiconductor thin film 9 having a high resistivity
When the dopant gas is supplied only from the central gas inlet 22 and the resistivity on the outer peripheral side becomes relatively steeply higher as approaching the outer peripheral portion as in the case of forming The uniformity of the resistivity distribution is realized by the combination with the gas inlet 21 which is in the forward direction with respect to the rotation direction of the single crystal substrate 6. Conversely, the low resistivity semiconductor thin film 9
When the dopant gas is supplied only from the central gas inlet 22 and the resistivity on the outer peripheral side relatively gradually increases as approaching the outer peripheral portion as in the case of forming The uniformity of the resistivity distribution is realized by the combination with the gas inlet 21 which is in the opposite direction to the rotation direction of the single crystal substrate 6.

Incidentally, the rotation direction of the semiconductor single crystal substrate 6 can be clockwise or counterclockwise, and the resistivity distribution can be controlled only by changing the rotation direction.

For example, while rotating the semiconductor single crystal substrate 6 clockwise, the gas inlet 22 at the center and the reaction vessel 4 are rotated.
When the dopant gas is supplied from the gas inlet 21 on the left side of the peripheral portion in the width direction and the resistivity of the peripheral portion of the semiconductor single crystal substrate 6 decreases sharply, the rotation of the semiconductor single crystal substrate 6 Reverse direction counterclockwise. Then
Since the dopant gas supplied from the gas inlet 21 is in a direction opposite to the rotation direction of the semiconductor single crystal substrate 6, the rate of change in resistivity in the peripheral portion of the semiconductor single crystal substrate 6 is relatively small.

[0025]

Next, the method and apparatus for growing a semiconductor thin film according to the present invention will be further described based on the examples performed by the present inventors. In the embodiment, the dopant gas is actually introduced from the respective inlets located at the peripheral portion in the width direction of the reaction vessel 4 and the uniformity of the in-plane resistivity is examined.

First, as shown in FIG.
Horizontal single-wafer-type vapor-phase growth apparatus 1
Was mounted on the susceptor 7. The width of the reaction vessel 4 of the growth apparatus 1 is 380 mm 2 and has a size capable of accommodating a large-diameter silicon single crystal substrate 6. Gas inlets 21, 22, 23
Is appropriately selected according to the gas to be introduced. For example, only the central gas inlet 22 may be larger in diameter than the peripheral gas inlets 21 and 23. As described above, since the reaction container 4 for processing the silicon single crystal substrate 6 having a diameter of 300 mm has a width of 380 mm, as an example, the gas inlet 22 at the center is provided at a position 190 mm from both ends, The gas introduction ports 21 and 23 are provided at a position 30 mm from the end.

Next, a plurality of gas inlets 21, 22, 23
Hydrogen gas containing 1.0% HF gas is supplied through the gas inlet 2 at a temperature of about 25 ° C. for 5 minutes in the silicon single crystal substrate 6 to spontaneously oxidize the surface of the silicon single crystal substrate 6. The film was removed. Then, the silicon single crystal substrate 6 is heated by energizing an infrared radiation heating lamp 5 which is a heating source provided on the upper outside of the reaction vessel 4, and the temperature of the silicon single crystal substrate 6 becomes 7.
When the temperature rises from 00 ° C., 2.0
% Hydrogen gas was introduced for one minute to remove organic substances on the main surface of the silicon single crystal substrate 6.

Further, the amount of electricity of the infrared radiation heating lamp 5 provided on the upper outside of the horizontal single wafer type vapor phase growth apparatus 1 was adjusted, and the temperature of the silicon single crystal substrate 6 was raised to 950 ° C. After the silicon single crystal substrate 6 reaches 950 ° C., while rotating the silicon single crystal substrate 6 clockwise, a combination described below is supplied from the gas inlet 2 of the horizontal single-wafer type vapor phase growth apparatus 1. Dopant gas (diborane (B ₂ H ₆ ) gas) and semiconductor source gas (trichlorosilane (SiHCl ₃ ) gas)
Was introduced for 2 minutes to obtain a semiconductor wafer in which a p-type silicon single crystal thin film 9 having an average thickness of about 2 μm was formed on the main surface of the silicon single crystal substrate 6. Subsequently, diborane (B ₂ H ₆ ) gas and trichlorosilane (SiHCl)
₃ ) The supply of the gas is stopped, and while the hydrogen gas is supplied only from the gas inlet 2 of the horizontal single-wafer type vapor phase growth apparatus 1, the energization of the infrared radiation heating lamp 5 is cut off to lower the temperature of the silicon single crystal substrate 6. After that, it was taken out of the reaction vessel 4.

Next, an example of a condition suitable for growing a silicon single crystal thin film 9 having a high resistivity and a low resistivity will be described. Table 1 is an example of such suitable conditions.

[Table 1]

Under the conditions shown in Table 1, high resistivity (target of 12 Ω · cm) and low resistivity (1.5 Ω · cm of resistivity)
When target silicon single crystal thin films 9 were grown, the in-plane resistivity variations were 2.5% and 2.0%, respectively.
It was found that the temperature was controlled to be extremely small. This is a high resistivity of 13%, which is conventionally obtained by a vapor phase growth method on a silicon single crystal substrate 6 having a diameter of 300 mm.
% And a low resistivity of 8%, the uniformity of the resistivity distribution is remarkably improved in this embodiment.

In the above embodiment, the gas inlets 21 and 2
Although the reference numerals 2 and 23 are arranged symmetrically so as to be aligned with the rotation center of the silicon single crystal substrate 6, the present invention is not limited to this, and may be arranged asymmetrically. For example, gas inlet 21,
The effects of the present invention can be increased by disposing the left and right sides 22 and 23 asymmetrically. In addition, gas inlet 21,
In 22 and 23, it is more effective if the gas flow rate is uniform.

In the above embodiment, the number of gas inlets located at the peripheral portion in the width direction of the reaction vessel is one for each of the left and right sides, but a plurality of gas inlets may be provided for each of the right and left sides. Further, the semiconductor material to be used is not limited to silicon, and another semiconductor material can be grown using another semiconductor material gas that can be vapor-phase grown. Further, the present invention can be applied not only to a semiconductor single crystal thin film but also to a vapor phase growth of a semiconductor polycrystal thin film.

[0033]

According to the present invention, the vapor phase growth is performed by limiting the dopant gas supplied from the peripheral portion in the width direction of the reaction vessel to either the forward direction or the reverse direction with respect to the rotation direction of the semiconductor single crystal substrate. This is a method for obtaining a semiconductor thin film having a uniform resistivity distribution. According to the present invention, as described above, the resistivity of the outer peripheral portion of a particularly large-diameter semiconductor single crystal substrate can be easily adjusted, so that the resistivity uniformity in the substrate can be further improved.

[Brief description of the drawings]

FIG. 1 is a schematic longitudinal sectional view showing a vapor phase growth apparatus used in one embodiment of a method for manufacturing a semiconductor wafer of the present invention.

FIG. 2 is a graph showing a resistivity distribution based on the results of an experiment performed based on the method of manufacturing a semiconductor wafer according to the present invention.

FIG. 3 is a schematic vertical sectional view showing a vapor phase growth apparatus used in one embodiment of a conventional method for manufacturing a semiconductor wafer.

FIG. 4 is a schematic cross-sectional view showing a structure of the vapor phase growth apparatus of FIG. 3 as viewed from above.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 Horizontal single-wafer type vapor phase growth apparatus 2, 21, 22, 23 Gas inlet 3 Gas exhaust port 4 Reaction vessel 5 Heat source (Infrared radiation heating lamp) 6 Semiconductor single crystal substrate (Silicon single crystal substrate) 7 Susceptor 8 Rotating shafts 11, 12, 13 Gas piping 30, 31, 32, 33, 34, 35, 36, 37, 3
8 Mass flow controller (MFC)

 ────────────────────────────────────────────────── ─── Continuing from the front page (72) Inventor, etc. 2-13-1, Isobe, Annaka-shi, Gunma F-term in the semiconductor isobe laboratory of Shin-Etsu Semiconductor Co., Ltd. 4K030 AA03 AA06 AA17 AA20 BA29 BB02 CA04 EA01 EA06 FA10 GA06 JA04 KA24 LA02 5F045 AC01 AC03 AC05 AC19 AD13 DA66 DP28 DQ06 EE04 EE15 EE20 EF02 EF08

Claims (6)

[Claims] 1. A semiconductor raw material gas and a dopant gas are supplied from a central portion in a width direction and a peripheral portion in a width direction of a reaction vessel in a direction parallel to a main surface of a semiconductor single crystal substrate rotating in the reaction vessel and in one direction. Then, in the method of manufacturing a semiconductor wafer for vapor-phase growing a semiconductor thin film on the semiconductor single crystal substrate, a dopant gas supplied from a peripheral portion in the width direction of the reaction vessel, with respect to the rotation direction of the semiconductor single crystal substrate A method for manufacturing a semiconductor wafer, wherein the supply is limited to only one of forward and reverse directions. 2. A method according to claim 1, wherein a dopant gas supplied from a peripheral portion in a width direction of the reaction container is moved in either a forward direction or a reverse direction with respect to a rotation direction of the semiconductor single crystal substrate in accordance with a resistivity of the semiconductor thin film. 2. The method for manufacturing a semiconductor wafer according to claim 1, wherein the method is changed. 3. According to a resistivity distribution of the semiconductor thin film,
2. The semiconductor wafer according to claim 1, wherein the dopant gas supplied from the peripheral portion in the width direction of the reaction vessel is changed to one of a forward direction and a reverse direction with respect to the rotation direction of the semiconductor single crystal substrate. Production method. 4. According to a resistivity distribution of the semiconductor thin film,
2. The method according to claim 1, wherein a rotation direction of the semiconductor single crystal substrate is changed. 5. The semiconductor wafer according to claim 1, wherein said semiconductor single crystal substrate is a silicon single crystal substrate, and said semiconductor thin film is a silicon single crystal thin film. Production method. 6. A semiconductor raw material gas and a dopant gas are supplied from a central portion in a width direction and a peripheral portion in a width direction of a reaction vessel in a direction parallel to a main surface of a semiconductor single crystal substrate rotating in the reaction vessel and in one direction. Then, in the method of manufacturing a semiconductor wafer in which a semiconductor thin film is vapor-phase grown on a semiconductor single crystal substrate, a rotation direction of the semiconductor single crystal substrate is changed according to a resistivity distribution of the semiconductor thin film. Semiconductor wafer manufacturing method.