JP2002231636A - Susceptor for chemical vapor deposition - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a susceptor for chemical vapor deposition with which no temperature difference is generated between regions of the susceptor resulting in a semiconductor substrate supported by the susceptor which will not cause slippage due to the temperature difference. SOLUTION: The susceptor for chemical vapor deposition comprises a ring- like carbon base, which has natural resistances of peripheral regions within 15% of the diameter from the outer peripheral edge and within 15% of the diameter from the inner peripheral edge and natural resistances of other inner regions than the peripheral regions and the latter natural resistances are greater by 100 μΩcm than the former natural resistances.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a susceptor for a chemical vapor deposition apparatus, and more particularly to a susceptor for a chemical vapor deposition apparatus in which a specific resistance value is changed depending on a region.

[0002]

2. Description of the Related Art As a semiconductor integrated circuit device becomes more highly integrated and more sophisticated, a silicon substrate having an epitaxial structure is often used as a starting material for this device. This epitaxial silicon substrate is obtained by chemical vapor deposition of a silicon single-crystal thin film on a silicon single-crystal substrate. Dozens of batch methods, 1
There is a single-wafer method that processes each sheet.
The reactor is roughly classified into a vertical type and a cylinder type depending on the structure of the reactor.

In this conventional chemical vapor deposition apparatus, a gas introduction nozzle for introducing a reaction gas into the apparatus from the outside, a blowout port provided on a side surface of a tip end of the gas introduction nozzle, and a base around the gas introduction nozzle are provided. A susceptor that is installed and supports the silicon single crystal substrate, is composed of a transparent quartz bell jar and a stainless steel bell jar surrounding the susceptor and the gas introduction nozzle to form a reaction furnace space, and a high-frequency induction heating device that heats the susceptor. ing.

In the above chemical vapor deposition apparatus, when the susceptor is heated by the high frequency induction heating device, the silicon single crystal substrate on the susceptor is heated. When the silicon single crystal substrate reaches a desired temperature, a reaction gas is guided from an external gas line through a gas introduction nozzle into a reaction furnace formed by a bell jar. The reaction gas is ejected from the outlet into the furnace, decomposed in the furnace, and vapor-phase grows a silicon single crystal thin film on a silicon single crystal substrate.

The temperature of the vertical vapor phase growth apparatus is raised in two stages. The temperature is raised to about 1000 ° C. in the first temperature rise, then to 1150 ° C. in the second temperature rise, and then the epitaxial growth is started. We are implementing. In the temperature region (1150 ° C.) where the epitaxial growth is performed, the radial temperature distribution in the susceptor plane is controlled to be substantially uniform.
In the first temperature rise from room temperature to 1000 ° C., a temperature difference of ± 200 ° C. occurs in the susceptor surface. This temperature distribution is high in the peripheral region of the susceptor (the outer and inner peripheral portions of the susceptor), and the internal region of the susceptor (the central portion of the susceptor).
At low. Due to these temperature differences, a temperature difference occurs in the silicon substrate set in the susceptor pocket, and a crystal defect called slip occurs. When this crystal defect occurs, there is a problem that the characteristics of the device vary.

[0006]

Therefore, there has been a demand for a susceptor in which a temperature difference does not occur between the regions of the susceptor and a slip does not occur on the silicon substrate supported by the susceptor due to the temperature difference.

The present invention has been made in view of the above circumstances, and provides a susceptor in which a temperature difference does not occur between the respective regions of the susceptor and a slip does not occur on the silicon substrate supported by the susceptor. With the goal.

[0008]

SUMMARY OF THE INVENTION In order to achieve the above object, a first aspect of the present invention is a high frequency induction heating apparatus in which a plurality of semiconductor single crystal substrates are supported by a bell jar installed in a reaction furnace. A susceptor for chemical vapor deposition for accommodating a susceptor heated by the method, introducing a reaction gas into a bell jar, and depositing a semiconductor single-crystal thin film on a semiconductor single-crystal substrate supported by the susceptor; The shape of the carbon base material is such that the specific resistance of the peripheral region in a region within 15% of the diameter from the outer peripheral edge and the region of 15% of the diameter from the internal peripheral edge, and the specific resistance of the internal region in other regions are different. A susceptor for chemical vapor deposition characterized in that the susceptor is different and the specific resistance of the internal region is larger than the specific resistance of the peripheral region by 100 μΩcm or more. I have.

[0009]

DESCRIPTION OF THE PREFERRED EMBODIMENTS A susceptor for chemical vapor deposition according to the present invention will be described below with reference to the accompanying drawings.

FIG. 1 is a plan view of a susceptor 1 for chemical vapor deposition according to the present invention. This susceptor 1 is made of a carbon base material, and has a circular through hole 2 through which a gas introduction nozzle penetrates at the center. It has no ring shape and has a plurality of susceptor pockets 3 on one side for storing and supporting a silicon substrate.
Are formed concentrically and continuously along the outer peripheral edge 1a of the susceptor 1. The susceptor pocket 3 has a circular shape similarly to the silicon substrate, and is recessed to such a depth that the silicon substrate is almost entirely accommodated.

Further, the susceptor 1 has a specific resistance value Rab in a peripheral region A within 15% of the diameter from the outer peripheral portion 1a and a peripheral region B within 15% of the diameter from the inner peripheral edge 1b forming the through hole 2; Resistance R of the internal region C
c, and the specific resistance value Rc of the internal region C is 100 μΩcm larger than the specific resistance value Rab of the peripheral regions A and B.
It is formed large as described above.

Next, a method of manufacturing a susceptor for chemical vapor deposition according to the present invention will be described.

A filler such as coke crushed and classified, a binder such as pitch, and an additive such as iron oxide are blended, kneaded, molded by CIP, calcined, graphitized and processed. You.

In the manufacturing process of the susceptor 1, the susceptor pocket 3 is formed by grinding and polishing in a working process. Further, the difference between the specific resistance value Rab of the peripheral region A and the specific region Rb of the peripheral region B of the susceptor 1 and the specific resistance value Rc of the internal region C is performed as follows.

That is, the kneaded material of the filler and the pitch adjusted to have the specific resistance value Rab after firing and graphitization is filled in the area corresponding to the peripheral area A and the peripheral area B of the CIP type susceptor 1, The kneaded material of the filler and the pitch adjusted to have the specific resistance value Rc after firing and graphitization is filled in a portion corresponding to the internal region C of No. 1. Thereafter, firing and graphitization are performed. The resulting graphite substrate is processed to obtain a susceptor 1 having desired resistance characteristics.

Further, a method for depositing a silicon single crystal thin film on a silicon single crystal substrate using the susceptor for chemical vapor deposition according to the present invention will be described.

FIG. 2 is a front sectional view of the chemical vapor deposition apparatus 11, in which the susceptor 1 for chemical vapor deposition according to the present invention is incorporated into the chemical vapor deposition apparatus 11, and the silicon supported by the susceptor 1. A silicon single crystal thin film is deposited on a single crystal substrate.

The chemical vapor deposition apparatus 11 includes a gas introduction nozzle 12 for introducing a reaction gas G from the outside to the chemical vapor deposition apparatus 11, and a silicon single crystal substrate W installed around the base of the gas introduction nozzle 12. Surrounding the susceptor 1 to be supported and the susceptor 1 and the gas introduction nozzle 12;
It comprises a transparent quartz bell jar 13 and a stainless steel bell jar 14 forming a reaction furnace space, and a coil 15 of a high frequency induction heating device for heating the susceptor 1.

Therefore, in order to deposit a silicon single crystal thin film on a silicon single crystal substrate supported by the susceptor 1 by using a chemical vapor deposition apparatus 11 as shown in FIG. Is stored in the susceptor pocket 3 and the supported susceptor 1 is stored in the transparent quartz bell jar 13, and the first temperature rise is 1000 ° C.
Temperature, and then to 1150 ° C. in the second heating.

At this time, the susceptor 1 is formed such that the specific resistance value Rc of the internal region C is larger than the specific resistance value Rab of the peripheral regions A and B by 100 μΩcm or more. And the calorific value increases,
As in the conventional case, the peripheral regions A and B, which are generated when the internal region C and the peripheral regions A and B have the same specific resistance value, are approximately 20%.
The non-uniform temperature in the susceptor surface, which is as high as 0 ° C., is eliminated,
The temperature difference between the internal region C and the peripheral regions A and B is reduced to 50 ° C.

When the susceptor 1 is heated to a substantially uniform temperature by the coil 15 of the high-frequency induction device, the silicon single crystal substrate W on the susceptor 1 is also heated substantially uniformly. When the silicon single crystal substrate W reaches a desired temperature, a reaction gas G is introduced into the transparent quartz bell jar 13 from the outside via the gas introduction nozzle 12. This reaction gas G
Is blown out from the outlet into the transparent quartz bell jar 13, is decomposed in the transparent quartz bell jar 13, and vapor-grows a silicon single crystal thin film on the silicon single crystal substrate W.

As described above, in the vapor phase growth process of a silicon single crystal thin film, the temperature difference can be reduced to 50 ° C. or less, and as a result, the slip length generated in the temperature raising process can be reduced by about 80%. Therefore, it is possible to reduce the defect rate of the silicon element substrate, reduce the manufacturing cost, and improve the quality.

[0023]

EXAMPLE (Test 1) In order to confirm the effect of reducing the temperature difference of the susceptor according to the present invention as shown in FIG. 1, a susceptor in which the specific resistance Rc and the specific resistance Rab were changed was used. The difference between the resistance value Rc and the specific resistance value Rab (Rc
-Rab), the temperature in the internal region C and the peripheral region A,
The relationship with the temperature difference in B was examined.

Results : shown in FIG.

As an example, the specific resistance difference (Rc-Ra)
By setting b) to 100 μΩcm, the conventional 190
It has been found that the temperature difference of 100 ° C. can be improved from 90 ° C. to 90 ° C. It was also found that the temperature difference can be reduced to 50 ° C. by setting the specific resistance value difference to 150 μΩcm.

On the other hand, the internal area C and the peripheral area A,
It was found that when no difference was provided in the specific resistance value of B (conventional example), the temperature difference reached 200 ° C.

When the difference in the specific resistance value is reduced, the temperature difference is gradually reduced.
cm (Comparative Example), it was found that the temperature difference was as large as 190 to 80 ° C.

(Test 2) A susceptor according to the present invention as shown in FIG. 1 and a susceptor having different specific resistance values Rc and Rab were used in a chemical vapor deposition apparatus as shown in FIG. The difference between the specific resistance value Rc and the specific resistance value Rab and the state of slip generated on the silicon single crystal substrate were examined.

Results : shown in FIG.

As an example, the specific resistance difference (Rc-Ra)
By making b) 100 to 150 μΩcm, about 4
It was found that the slip length was reduced to 0 mm / substrate or less.

On the other hand, when there is no difference in the specific resistance value (conventional example), it was found that the length of the slip was extremely large at 200 mm / substrate.

When the difference in the specific resistance value is reduced, the length of the slip is gradually reduced.
At 80 μΩcm (comparative example), the slip length is 190 to
It was found to be as large as 110 mm / substrate.

[0033]

According to the susceptor for chemical vapor deposition according to the present invention, a temperature difference does not occur between the regions of the susceptor, and the semiconductor substrate supported by the susceptor does not generate a slip due to the temperature difference. Susceptor can be provided.

That is, the ring-shaped carbon base material forming the susceptor has a specific resistance value in the peripheral region in a region within 15% of the diameter from the outer peripheral edge and in a region within 15% of the diameter from the inner peripheral edge, and the other values. Since the specific resistance value of the internal region is different from the specific resistance value of the internal region and the specific resistance value of the internal region is larger than the specific resistance value of the peripheral region by 100 μΩcm or more, it is possible to improve the temperature difference in the susceptor plane during the epitaxial heating process. The temperature difference is reduced,
The slip length generated during the temperature rise process can also be greatly reduced, reducing the defect rate of semiconductor element substrates, reducing manufacturing costs,
The quality can be improved.

[Brief description of the drawings]

FIG. 1 is a plan view of a susceptor for chemical vapor deposition according to the present invention.

FIG. 2 is a conceptual diagram of a chemical vapor deposition apparatus in which a susceptor for chemical vapor deposition according to the present invention is incorporated and used.

FIG. 3 is a test result diagram showing a relationship between a specific resistance value difference and a temperature difference in an example using a susceptor for chemical vapor deposition according to the present invention.

FIG. 4 is a test result diagram showing a relationship between a specific resistance value difference and a slip length of an example using a susceptor for chemical vapor deposition according to the present invention.

[Explanation of symbols]

 Reference Signs List 1 susceptor for chemical vapor deposition 1a outer peripheral edge 1b inner peripheral edge 2 through hole 3 susceptor pocket A peripheral area B peripheral area C internal area

Claims (1)

[Claims] 1. A susceptor that supports a plurality of semiconductor single crystal substrates and is heated by a high-frequency induction heating device is housed in a bell jar installed in a reaction furnace, and a reaction gas is introduced into the bell jar to be supported by the susceptor. A susceptor for chemical vapor deposition for depositing a semiconductor single-crystal thin film on a semiconductor single-crystal substrate, wherein a ring-shaped carbon substrate forming the susceptor has a region within 15% of a diameter from an outer periphery and an inner periphery. The resistivity of the peripheral region in the region within 15% of the diameter is different from the resistivity of the inner region in the other region, and the resistivity of the inner region is 100 μΩcm or more larger than the resistivity of the peripheral region. A susceptor for chemical vapor deposition characterized by being large.