Semiconductor device manufacturing: process – Formation of semiconductive active region on any substrate
Reexamination Certificate
1998-08-03
2001-05-01
Nelms, David (Department: 2818)
Semiconductor device manufacturing: process
Formation of semiconductive active region on any substrate
C438S604000, C117S104000
Reexamination Certificate
active
06225195
ABSTRACT:
BACKGROUND OF THE INVENTION 1. FIELD OF THE INVENTION
The present invention relates to a method for manufacturing a group III-V compound semiconductor useful for a light-emitting device, and the like, represented by the general formula In
x
Ga
y
Al
z
N (where x+y+z=1, 0≦x≦1, 0≦y≦1, and 0≦z≦1).
2. Description of the Related Art
There has been known a group III-V compound semiconductor represented by the general formula In
x
Ga
y
Al
z
N (where x+y+z=1, 0≦x≦1, 0≦y≦1, and 0≦z≦1) as a material for a light-emitting device such as an ultraviolet, blue, or green light-emitting diode, or an ultraviolet, blue, or green laser diode. Hereinafter, in some cases, the x, y, and z in the general formula may be referred to as InN mixed crystal ratio, GaN mixed crystal ratio, and AlN mixed crystal ratio, respectively. In the group III-V compound semiconductors, especially with the one containing 10% or more of InN mixed crystal ratio, the emission wavelength in a visible region can be regulated in accordance with the InN mixed crystal ratio, and hence it is especially important for the display applications.
Examples of the manufacturing method of the group III-V compound semiconductor include molecular-beam epitaxy (hereinafter, may be referred to as MBE) method, metalorganic vapor phase epitaxy (hereinafter, may be referred to as MOVPE) method, and hydride vapor phase epitaxy (hereinafter, may be referred to as HVPE) method. Among these methods, MOVPE method enables the uniform crystal growth over a large area, and hence it is important.
There are known Be, Ca, Mg, Zn, C, and the like as acceptor type dopants for imparting the p-type conductivity to the compound semiconductor. Of these, Mg is capable of implementing higher p-type conductivity than other dopants, and hence it is widely used at present. The following description will be given by taking Mg as an example, however, it is well known that there occur the same troubles with the other p-type dopants.
As Mg sources for use in MOVPE method, there are known bis-cyclopentadienylmagnesium ((C
5
H
5
)
2
Mg, hereinafter, may be referred to as Cp
2
Mg), bis-methylcyclopentadienylmagnesium ((C
5
H
4
CH
3
)
2
Mg, hereinafter, may be referred to as MCp
2
Mg), bis-ethylcyclopentadienylmagnesium ((C
5
H
4
C
2
H
5
)
2
Mg, hereinafter, may be referred to as ECp
2
Mg), and the like. Any of these will be strongly adsorbed on gas piping, a reactor, and the like, and hence the incorporation of the dopants into crystal starts with a delay after the supply of a dopant source. Also, there occurs a trouble that the incorporation of dopants is gradually caused unintentionally in the following runs after the growth in which a dopant source has been flown. These are generally referred to as the memory effect of a dopant.
The large deficiency of the memory effect is especially in that the layer required to be highly pure for use in the emitting layer of a light-emitting device is doped unintentionally with a dopant, and it makes difficult to obtain a layer having a desired quality. These dopant sources react with the materials constituting gas piping or a reactor, after which impurities are gradually released from the materials, also causing a trouble that a layer having a desired high quality cannot be grown. Further, in large equipment of industrial importance, a large amount of dopant source must be supplied, and hence these troubles have been particularly serious problems.
SUMMARY OF THE INVENTION
An object of the present invention is to provide a method for manufacturing a high-quality group III-V compound semiconductor successively with reducing the memory effect of a dopant
As a result of conducting various investigations in an attempt to solve the above problems, the inventors have found that by employing two growth reactors, e.g., one reactor in which a raw material having the memory effect is not used, and another reactor in which a raw material having a memory effect is used, and growing layered structures required for a light-emitting device successively, thereby reducing the memory effect of a dopant more than in the case where the growth is performed in one growth reactor. This enables the stable manufacturing of a high-quality nitride system group III-V compound semiconductor repeatedly.
The present invention relates to [1] a method for manufacturing a group III-V compound semiconductor represented by the general formula In
x
Ga
y
Al
z
N (where x+y+z=1, 0≦x≦1, 0≦y≦1, and 0≦z≦1) by metalorganic vapor phase epitaxy method, the group III-V compound semiconductor having a semiconductor layer consisting of a p-type dopant-nondoped layer, and a semiconductor layer including a p-type dopant-doped layer, wherein a reactor for growing the semiconductor layer consisting of a p-type dopant-nondoped layer and a reactor for doping a p-type dopant are mutually different.
The present invention also relates to [2] a method for manufacturing a group III-V compound semiconductor represented by the general formula In
x
Ga
y
Al
z
N (where x+y+z=1, 0≦x≦1, 0≦y≦1, and 0≦z≦1) by metalorganic vapor phase epitaxy method, the group III-V compound semiconductor having a semiconductor layer consisting of a p-type dopant-nondoped layer, and a semiconductor layer including a p-type dopant-doped layer, wherein the method comprises the steps of: (1) growing a semiconductor including one or more layers consisting of a p-type dopant-nondoped layer in one reactor, and taking it out of the reactor, and (2) putting the semiconductor obtained in the reactor again to grow a semiconductor layer including a p-type dopant-doped layer on the semiconductor layer consisting of a p-type dopant-nondoped layer in this order, and at least one of the steps (1) or (2) is repeated plural times.
According to the present invention, the influence by contamination in the growth reactor can be suppressed and the repeating reproducibility can be largely improved, by sharing the growth of the layered structure of a light-emitting device with the first and second growth reactors, or by carrying out the growth steps of the layered structure of the light-emitting device separately even if one growth reactor is used. The yield of manufacturing an epitaxial wafer for a high luminance light-emitting device can be greatly increased, and the present invention is extremely useful, and has a great industrial importance.
REFERENCES:
patent: 5381756 (1995-01-01), Kondo et al.
patent: 5458085 (1995-10-01), Kondo et al.
patent: 0716457 A2 (1996-06-01), None
patent: 621511 (1994-01-01), None
patent: 818159 (1996-01-01), None
patent: 936429 (1997-02-01), None
Y. Ohba et al., Journal of Crystal Growth 145 (1994) p. 214-218.
Shuji Nakamura et al., Jpn. J. Appl. Phys. vol. 34 (1995) pp. L797-L799, Part 2, No. 7A, Jul. 1, 1995.
Shuji Nakamura et al., Jpn. J. Appl. Phys. vol. 34 (1995) pp. L1332-L1335, Part 2, No. 10B, Oct. 15, 1995.
Hisayoshi Hanai et al., Technical Report of IEICE, ED96-29, CPM96-14 (1996-05).
C.J. Sun et al., J. Appl. Phys. 76 (1), Jul. 1, 1994.
Takashi Matsuoka et al., Optoelectronics—Devices and Technologies, vol. 5, No. 1, pp. 53-61, Jun., 1990.
Iyechika Yasushi
Ono Yoshinobu
Shimizu Masaya
Takada Tomoyuki
Birch & Stewart Kolasch & Birch, LLP
Dang Phuc T.
Nelms David
Sumitomo Chemical Company Limited
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