Semiconductor device manufacturing: process – Radiation or energy treatment modifying properties of... – Compound semiconductor
Reexamination Certificate
1998-10-26
2002-07-16
Whitehead, Jr., Carl (Department: 2822)
Semiconductor device manufacturing: process
Radiation or energy treatment modifying properties of...
Compound semiconductor
C438S572000, C438S573000, C438S590000, C438S602000, C438S604000, C438S606000, C438S779000
Reexamination Certificate
active
06420283
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a III-V group compound semiconductor substrate containing nitrogen as its main component, and a method for producing the same. More specifically, the present invention relates to a III-V group compound semiconductor substrate containing nitrogen as its main component, preferably used as a substrate of a light-emitting element, and a method for producing the same.
2. Description of the Related Art
In recent years, blue light-emitting diodes with high brightness have been commercialized, utilizing a GaN compound semiconductor as a material for a light-emitting layer. Therefore, there has been growing interest in a nitride semiconductor as a material for a light-emitting device. Conventionally, a nitride semiconductor is grown by using a hydride vapor phase epitaxy method (hereinafter, referred to as an “HVPE method”), metal organic chemical vapor deposition (hereinafter, referred to as an “MOCVD method”), and a molecular beam epitaxy method (hereinafter, referred to as an “MBE method”). It is preferable that a substrate on which crystal is grown is made of substantially the same material as that for a film to be grown on the substrate. More specifically, it is preferable that a nitride semiconductor is grown on a nitride single crystal substrate. However, it is difficult to obtain a nitride single crystal substrate with a large scale, so that a sapphire substrate (Japanese Laid-open Publication Nos. 2-229476 and 4-297023), an SiC substrate (Japanese Laid-open Publication No. 8-203834), a spinel substrate, a GaAs substrate, and the like have been used in the past.
As described above, in the case where a sapphire substrate is used as a substrate on which a nitride semiconductor is grown, there is an advantage that a sapphire substrate with high purity is easily available. However, there are disadvantages that a sapphire substrate and a nitride semiconductor grown on the substrate have lattice mismatching, and the difference in thermal expansion coefficient therebetween is large. Due to these disadvantages, a lot of defects of about 10
10
cm
−2
are caused in a growth layer of a nitride semiconductor, and furthermore, potential stress is generated in the growth layer.
In the case where an SiC substrate is used as a substrate on which a nitride semiconductor is grown, the increase in defects caused by the lattice mismatching can be relaxed. However, the problem of potential stress caused by the difference in thermal expansion coefficient remains unsolved, which results in cracks on the surface of a growth film.
Furthermore, in the case where a GaAs substrate is used as a substrate on which a nitride semiconductor is grown, a crystal growth temperature is limited to a temperature for generating a GaAs layer. Thus, a crystal growth temperature in the vicinity of 1000° C. required for growing a nitride semiconductor layer cannot be used. If semiconductor crystal is grown at such a low temperature, a growth film is likely to assume a configuration including cubic crystal and hexagonal crystal. This makes it difficult to grow good quality crystal.
SUMMARY OF THE INVENTION
A compound semiconductor substrate of the present invention, includes: a mica substrate; and a III-V group compound semiconductor layer containing nitrogen as its main component grown on the mica substrate.
In one embodiment of the present invention, the above-mentioned compound semiconductor substrate further includes an intermediate layer between the mica substrate and the III-V group compound semiconductor layer.
In another embodiment of the present invention, the above-mentioned compound semiconductor substrate further includes a mask pattern layer on a side of the mica substrate on which the III-V group compound semiconductor layer is grown.
In another embodiment of the present invention, the mica substrate is made of crystal having a composition of &agr;
1−x
&bgr;
3−y
(&ggr;
4
O
10
)&dgr;
2
, wherein
O≦x≦0.5;
O≦y≦1;
&agr; is selected from the group consisting of K, Ca, Na, Ba, NH
4
, and H
3
O;
&bgr; is selected from the group consisting of Al, Fe, Mg, Mn, Li, Zn, V, Cr, and Ti;
&ggr; is one or more element selected from the group consisting of Si, Al, Be, and Fe; and
&dgr; is F or OH.
In another embodiment of the present invention, the mica substrate is made of crystal having a composition of KMg
3
(Si
3
AlO
10
)F
2
.
In another embodiment of the present invention, the mica substrate is made of crystal having a composition of KMg
3
(Si
3
AlO
10
)(OH)
2
.
A method for producing a compound semiconductor substrate of the present invention, includes the step of growing a III-V group compound semiconductor layer containing nitrogen as its main component on a mica substrate.
In one embodiment of the present invention, the above-mentioned method for producing a compound semiconductor substrate further includes the step of providing an intermediate layer between the mica substrate and the III-V group compound semiconductor layer.
In another embodiment of the present invention, the above-mentioned method for producing a compound semiconductor substrate further includes the step of providing a mask pattern layer on a side of the mica substrate on which the III-V group compound semiconductor layer is grown.
In another embodiment of the present invention, the above-mentioned method for producing a compound semiconductor substrate further includes the step of peeling the mica substrate from the III-V group compound semiconductor layer.
In another embodiment of the present invention, the mica substrate is made of crystal having a composition of a &agr;
1−x
&bgr;
3−y
(&ggr;
4
O
10
)&dgr;
2
, wherein
O≦x≦0.5;
O≦y≦1;
&agr; is selected from the group consisting of K, Ca, Na, Ba, NH
4
, and H
3
O;
&bgr; is selected from the group consisting of Al, Fe, Mg, Mn, Li, Zn, V, Cr, and Ti;
&ggr; is one or more element selected from the group consisting of Si, Al, Be, and Fe; and
&dgr; is F or OH.
In another embodiment of the present invention, the mica substrate is made of crystal having a composition of KMg
3
(Si
3
AlO
10
)F
2
.
In another embodiment of the present invention, the mica substrate is made of crystal having a composition of KMg
3
(Si
3
AlO
10
)(OH)
2
.
In another embodiment of the present invention, the step of growing the III-V group compound semiconductor layer on the mica substrate includes the steps of: forming a mask pattern layer on the mica substrate; forming an intermediate layer in a region of the mica substrate where the mask pattern layer is not formed; growing a first III-V group compound semiconductor layer containing nitrogen as its main component on the intermediate layer by a first growth method; and growing a second III-V group compound semiconductor layer having the same composition as the composition of the first III-V group compound semiconductor layer on the first III-V group compound semiconductor layer by a second growth method, and the method further includes the step of peeling the mica substrate from the first and second III-V group compound semiconductor layers.
A light-emitting element of the present invention includes a semiconductor layered structure including at least a light-emitting layer on the above-mentioned III-V group compound semiconductor layer.
A method for producing a light-emitting element of the present invention includes the step of providing a semiconductor layered structure including at least a light-emitting layer on a III-V group compound semiconductor layer, wherein the III-V group compound semiconductor layer is produced during the above-mentioned step of growing the III-V group compound semiconductor layer.
According to the present invention, a compound semiconductor substrate including a III-V group compound crystal layer with high crystallinity containing nitrogen as its main component can be obtained by applying a mica substrate to a substrate for growing a III-V group compound semiconductor containing nitrogen as its main componen
Ogawa Atsushi
Yuasa Takayuki
Duong Khanh
Jr. Carl Whitehead
Morrison & Foerster / LLP
Sharp Kabushiki Kaisha
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