JP2001093848A - Method for manufacturing semiconductor device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To make satisfactory epitaxial growth of a semiconductor layer to take place by suppressing the formation of oxide or mixture of moisture into the semiconductor layer at melting of semiconductor material. SOLUTION: A melted semiconductor material is supplied from a crucible 2 disposed above processing containers 1 for holding their semiconductor wafers W into the containers 1. At melting of a solid semiconductor material in the crucible 2, a processing chamber 5 is evacuated by a vacuum pump 25. As a result, oxide or moisture generated at melting of the semiconductor material is discharged to the outside of the chamber 5. Thereafter, semiconductor layers are epitaxially grown on their semiconductor wafers W within the chamber 5 in purified state.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a method for manufacturing a semiconductor device manufactured by epitaxially growing a semiconductor layer on a semiconductor substrate.

[0002]

2. Description of the Related Art For example, a manufacturing process of a light emitting element such as a light emitting diode includes a step of epitaxially growing a compound semiconductor layer of the same kind as a semiconductor substrate on a compound semiconductor substrate such as gallium phosphide or gallium arsenide. In this epitaxial growth, a semiconductor substrate is arranged in a processing chamber, a crucible is arranged above the semiconductor substrate, a melt of the compound semiconductor is supplied from the crucible to the semiconductor substrate, and the compound semiconductor is deposited on the semiconductor substrate. Done.

[0003] In a crucible, solid particles of a compound semiconductor are put and heated and melted to produce a melt of the compound semiconductor.

[0004]

However, in the process of heating and melting solid particles of a compound semiconductor in a crucible,
There is a problem that oxides and moisture mixed in the compound semiconductor solid or melt evaporate and become gaseous and diffuse into the processing chamber. These oxide gases and moisture (water vapor) are taken into the semiconductor layer epitaxially grown on the surface of the semiconductor substrate, and deteriorate the quality of the semiconductor layer.

Accordingly, an object of the present invention is to solve the above-mentioned technical problems and to suppress the incorporation of oxide or moisture generated when a semiconductor material is melted into a semiconductor layer, thereby forming a good semiconductor layer by epitaxial growth. It is an object of the present invention to provide a method for manufacturing a semiconductor device which can be performed.

[0006]

Means for Solving the Problems and Effects of the Invention In order to achieve the above object, the invention according to claim 1 includes a step of arranging a semiconductor substrate in a processing chamber and a step of heating a semiconductor material in the processing chamber. A heating / melting step of melting, a vacuum evacuation step of evacuating the processing chamber in parallel with the heating / melting step, and supplying a semiconductor material melted by the heating / melting step to a surface of the semiconductor substrate; A step of epitaxially growing a semiconductor layer on a surface of a semiconductor substrate.

According to the present invention, the processing chamber is evacuated in the heating and melting step of heating and melting the semiconductor material. Thus, the oxide gas and water vapor generated in the heating and melting step are guided to the outside of the processing chamber. Therefore, in the subsequent epitaxial growth step, a high-quality semiconductor layer with almost no oxide or moisture mixed therein can be formed. Thereby, the operation performance of the semiconductor device can be improved, and the yield can be improved. In the evacuation step,
For example, it is preferable to perform exhaust until the pressure in the processing chamber becomes 10 Torr or less.

It is preferable that a heating means such as a heater is provided on the outer periphery of the processing chamber to epitaxially grow the semiconductor layer while controlling the temperature of the substrate in the processing chamber. The semiconductor substrate and the semiconductor material may be a compound semiconductor. In this case, the compound semiconductor may be a group III-V compound semiconductor represented by gallium phosphide and gallium arsenide.

[0009]

Embodiments of the present invention will be described below in detail with reference to the accompanying drawings. FIG. 1 is a schematic cross-sectional view showing the configuration of an epitaxial growth apparatus (liquid phase epitaxial growth (LPE) apparatus) for performing a method of manufacturing a semiconductor device according to one embodiment of the present invention. This apparatus includes a processing chamber 5 containing a plurality of processing vessels 1 arranged in a vertical direction and a crucible 2 arranged above a group of these processing vessels. The processing chamber 5 is made of, for example, quartz. The processing chamber 5 has a gas inlet 11 on the lower bottom surface of the group of processing vessels 1 and an inner cylinder body 51 that is open at the top and is covered by the inner cylinder body 51. It has a double cylinder structure having an outer cylinder 52.

An exhaust port 12 is formed in the lower portion of the side surface of the outer cylinder 52, and the gas introduction port 11 is provided in the processing chamber 5.
Through the inside of the inner cylinder 51, and the inner cylinder 51 and the outer cylinder 52
And a gas flow passage extending to the exhaust port 12 through the space between them. Each processing vessel 1 contains one or more gallium phosphide compound semiconductor wafers W.
The temperature of the semiconductor wafer W is controlled by a heater 6 arranged along the outer peripheral surface of the processing chamber 5 to a temperature suitable for epitaxial growth (for example, about 800 ° C.).

A heating mechanism 2a such as a heater is provided in the crucible 2 above the processing vessel 1 group. This crucible 2
Inside, solid particles of gallium and gallium phosphorus are contained. Then, by heating this by the heating mechanism 2a, a gallium melt mixed with gallium phosphorus (molten semiconductor material) is obtained. This melt is supplied to a plurality of processing vessels 1 below the melt by a supply mechanism (not shown). Therefore, in the processing container 1,
A melt of gallium mixed with gallium phosphide comes into contact with the surface of the semiconductor wafer W, and gallium phosphide precipitates with cooling on the surface of the semiconductor wafer W, thereby achieving epitaxial growth of the gallium phosphide semiconductor layer. Is done.

The gas inlet 11 formed in the processing chamber 5 has:
It is connected to the carrier gas supply device 20 via an air supply valve VI. The carrier gas supply device 20 supplies a carrier gas made of a gas that is not easily decomposed, such as a hydrogen gas, a nitrogen gas, or an argon gas, into the processing chamber 5 while the semiconductor layer is being epitaxially grown on the surface of the semiconductor wafer W. To supply. On the other hand, an exhaust port 12 formed in the processing chamber 5 is connected to a branch pipe 9 that branches into two. One branch pipe 91 of the branch pipe 9 is connected to a vacuum pump 2 as a vacuum exhaust mechanism via a first exhaust valve VO1.
5. Also, the other branch pipe 92 of the branch pipe 9
Is connected to an exhaust pipe 28 via a second exhaust valve VO2. The exhaust pipe 28 is connected to an appropriate exhaust facility such as an exhaust duct provided in a semiconductor manufacturing factory.

An air supply valve VI, and first and second
The exhaust valves VO1 and VO2 are controlled to be opened and closed by the control device 30. When epitaxially growing a semiconductor layer on the surface of the semiconductor substrate W, first,
The heating mechanism 2a is brought into an operating state, and a heating and melting step for melting the semiconductor material in the crucible 2 is performed. In this heating and melting step, the control device 30 closes the air supply valve VI and the second exhaust valve VO2, opens the first exhaust valve VO1, and stops the carrier gas supply device 20, The vacuum pump 25 is set to the operating state. Thus, the evacuation step is performed in parallel with the heating and melting step, and the processing chamber 5 is evacuated. Thereby, the oxide gas and water vapor generated from the semiconductor material in the crucible 2 are carried out to the outside of the processing chamber 5 through the exhaust port 12, and the inside of the processing chamber 5 contains impurities (oxide or moisture). Not kept in a clean state. In order to sufficiently remove oxides or moisture in the processing chamber 5, the processing chamber 5 is preferably evacuated so that the pressure in the processing chamber 5 is 10 Torr or less.

When the molten semiconductor material is produced in the crucible 2, the molten semiconductor material is supplied to a semiconductor wafer W in the processing vessel 1 below the molten semiconductor material, and a gallium phosphorus compound semiconductor layer is formed on the surface of the semiconductor wafer W. Is epitaxially grown. In this epitaxial growth step, the control device 30 controls the air supply valve VI and the second exhaust valve VO2.
Is opened, and the first exhaust valve VO1 is closed. In addition, the control device 30 controls the vacuum pump 2
5 is stopped, and the carrier gas supply device 2
0 is activated.

As a result, a gas flow of the carrier gas is formed in the processing chamber 5 from the gas inlet 11 to the exhaust port 12 through the group of processing vessels 1 and epitaxial growth is performed in this state. When mixing of the oxide or moisture in the molten semiconductor material supplied into the processing container 1 into the semiconductor layer becomes a problem, the evacuation step is performed during a period after the molten semiconductor material is supplied to the processing container 1. Preferably, it is continued. However, in this case, by controlling the heater 6, the temperature of the semiconductor wafer W is set to a temperature higher than 800 ° C. (temperature at which deposition of the molten semiconductor material (gallium phosphorus) occurs) (preferably, about 850 ° C. to 900 ° C.). It is preferable to prevent the epitaxial growth (precipitation of gallium phosphorus) of the semiconductor layer from occurring on the surface of the semiconductor wafer W by controlling the thickness of the semiconductor wafer W. After the time required for removing the oxide or moisture in the molten semiconductor material in the processing chamber 1 has elapsed, the semiconductor wafer W is controlled by the heater 6.
The epitaxial growth may be started by controlling the temperature at about 800 ° C. At the time of this epitaxial growth, the evacuation is stopped and an air flow of the carrier gas is formed in the processing chamber 5. In this way, it is possible to more reliably prevent oxides or moisture from being taken into the epitaxial growth layer.

As described above, according to the method of this embodiment, the processing chamber 5 is evacuated prior to the epitaxial growth step, so that oxides and moisture in the semiconductor material are discharged outside the processing chamber 5. Can be eliminated. Therefore, since the semiconductor layer can be epitaxially grown in a clean atmosphere in which no oxide or moisture is present, the semiconductor layer has a very high quality, and the semiconductor device manufactured in this manner has excellent operation characteristics. be able to. That is, for example, if this method is applied to the manufacture of a light-emitting element such as a light-emitting diode, a light-emitting element with high luminous efficiency and high luminance can be manufactured.

Note that the present invention can be implemented in embodiments other than the above-described embodiment. For example, in the above-described embodiment, a configuration in which a plurality of stages of processing vessels 1 are used has been described. However, a single-stage processing vessel may be used, or semiconductor wafers W to be processed collectively in the processing chamber 5 may be used. The number of sheets may be one or an arbitrary number of sheets. Further, in the above-described embodiment, an example in which the gas flow of the carrier gas is formed in the processing chamber 5 in the vertical direction has been described. However, when a horizontally long processing chamber is used, the direction of the gas flow is It may be in the horizontal direction (horizontal direction).

Further, in the above embodiment, the case where the gallium phosphide compound semiconductor layer is epitaxially grown on the gallium phosphide compound semiconductor substrate is taken as an example. The present invention can be applied. Further, the present invention may be applied to epitaxial growth of general semiconductors such as silicon and germanium other than the compound semiconductor. In addition, various changes can be made within the scope of the matters described in the claims.

[Brief description of the drawings]

FIG. 1 is an illustrative sectional view showing a configuration of an epitaxial growth apparatus for performing a method of manufacturing a semiconductor device according to an embodiment of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Processing container 2 Crucible 2a Heating mechanism 5 Processing chamber 6 Heater 11 Gas inlet 12 Exhaust port 20 Carrier gas supply device 25 Vacuum pump 28 Exhaust pipe 30 Control device VI Air supply valve VO1 First exhaust valve VO2 Second exhaust valve W Gallium phosphorus compound semiconductor wafer

 ────────────────────────────────────────────────── ─── Continuing from the front page (72) Inventor Tetsuji Matsuo 21-Family, Rishi Co., Ltd., Ryoto-ku, Kyoto, Japan 21F R-term (reference) 5F041 AA40 CA37 CA63 5F053 AA03 AA26 AA44 AA48 BB04 BB23 BB52 BB53 BB57 DD03 DD07 DD20 FF01 GG01 HH01 HH04 LL02 PP03 PP20 RR04 RR11

Claims (1)

[Claims] A step of arranging a semiconductor substrate in a processing chamber; a step of heating and melting a semiconductor material in the processing chamber; and a step of evacuating the processing chamber in parallel with the step of heating and melting. A method of manufacturing a semiconductor device, comprising: an evacuation step; and a step of supplying a semiconductor material melted by the heating and melting step to a surface of the semiconductor substrate to epitaxially grow a semiconductor layer on the surface of the semiconductor substrate. .