JP2003229599A - Boron phosphide type semiconductor device, method of manufacturing it, light-emitting diode and boron phosphide type semiconductor layer - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a boron phosphide type semiconductor device, in which a characteristic is advanced, providing a polycrystalline boron phosphide type semiconductor layer stably including twins which have twin faces having specific crystal directions. <P>SOLUTION: A substrate is formed with (111) Si single crystals having surfaces constructed with (111) crystal faces, a laminated boron phosphide type semiconductor layer is constructed with a polycrystal layer in which a plurality of single crystal body, which has a bottom face formed with (111) the crystal face and also is surrounded by a face equivalent to (111) the crystal face, constructed with square spindle shape boron phosphide type semiconductor crystals are got together; further, the single crystal body has a twin boundary surface having a tilt angle of 60 degrees against (110) a crystal orientation of the substrate. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a crystal structure of a boron phosphide-based semiconductor layer, which is formed on a silicon (Si) single crystal (silicon) substrate and is suitable for obtaining a boron phosphide-based semiconductor element, and the same. The present invention relates to a boron phosphide-based semiconductor device having:

[0002]

2. Description of the Related Art Conventionally, boron (B) and phosphorus (P)
A light emitting diode (LE) is formed by using boron phosphide (BP), which is a kind of boron phosphide-based semiconductor containing
D) or a technique for forming a semiconductor light emitting device such as a laser diode (LD) is known (US Pat. No. 6,063).
9, 021). A conventional boron phosphide-based semiconductor light emitting device is configured using, for example, a laminated structure including a boron phosphide layer formed on a substrate made of silicon single crystal (silicon) as a buffer layer (see the above US Patent No. 6,06
9, 021). Recently, a laminated structure for a semiconductor light emitting device having a pn junction type double hetero structure having a wide bandgap boron phosphide layer as a barrier (cladding) layer has been also invented (Japanese Patent Application No. 2001-2001). 1582
82).

It has been conventionally known that a single crystal layer of boron phosphide having the same crystal plane as that of the substrate surface grows on a silicon substrate. For example, the surface is {1
It is known that a boron phosphide single crystal layer composed of {100} crystal planes stacked in parallel to the substrate surface grows on a {100} -Si single crystal substrate having a {00} crystal plane (Katsu Shono). Fusa, "Semiconductor Technology (above)" (June 25, 1992)
(See page 77, 9th edition, published by The University of Tokyo Press).
In addition, twinning on the silicon substrate
It is also known to be able to grow a boron phosphide single crystal layer that does not contain any element (see "Semiconductor Technology (above)", page 98). On the other hand, it is known that a {100} -boron phosphide single crystal layer containing twins can be obtained (see "Semiconductor Technology (above)", pages 99 to 100).

[0004]

The prior art discloses that the twin crystals contained in the boron phosphide layer have a characteristic of relaxing the mismatch rate between the crystal lattices (the above-mentioned " Semiconductor Technology (above) ", p. 100). Therefore, the use of the boron phosphide-based semiconductor layer containing twins can contribute to obtaining an LED having excellent characteristics, for example, light emission intensity. However, as disclosed in the prior art, it is difficult to stably obtain a boron phosphide-based semiconductor layer containing twins. That is, conventionally, the requirements for producing a boron phosphide-based semiconductor layer that stably contains twins have not been clarified, so that, for example, it is difficult to stably obtain a light-emitting element having excellent emission intensity. Is coming.

An object of the present invention is to provide a boron phosphide-based semiconductor layer having a crystal structure capable of stably containing twins. The present invention also provides a boron phosphide-based semiconductor device having improved characteristics by including a polycrystalline boron phosphide-based semiconductor layer that stably contains twins having twin planes in a specific crystal direction. . Here, the boron phosphide-based semiconductor layer having a crystal structure, which is the object of the present invention, does not consist of a conventional film-like single crystal, but a twin boundary surface (twin crystal surface) (CW Van. , "Chemical Crystallography" (1965
(See page 75-76, the first edition published by Baifukan Co., Ltd. on March 15th.)
Is a boron phosphide-based semiconductor layer composed of a polycrystal formed by assembling single crystal bodies having different crystal directions.

[0006]

Means for Solving the Problems That is, the present invention provides (1)
A substrate made of silicon (Si) single crystal, and a boron phosphide-based semiconductor layer formed of a boron phosphide-based semiconductor crystal formed on the surface of the substrate and having the same crystal plane as the crystal plane constituting the surface of the substrate In a boron phosphide-based semiconductor device having a surface of the substrate, the surface of the substrate is a {111} crystal plane {1
11} -Si single crystal, wherein the boron phosphide-based semiconductor layer has a bottom surface composed of the {111} crystal planes of the boron phosphide-based semiconductor crystal arranged in parallel with the {111} crystal planes of the substrate, Further, it is composed of a polycrystalline layer in which a plurality of tetragonal pyramidal boron phosphide-based semiconductor crystal single crystals are surrounded by a plane equivalent to the {111} crystal plane, and the single crystal is
A boron phosphide-based semiconductor device having a twin boundary surface inclined at an angle of 60 degrees with respect to the <110> crystal direction of the substrate. Is.

The present invention also includes (2) a heterojunction formed by laminating a III-V group compound semiconductor layer on the boron phosphide-based semiconductor layer, wherein the III-V group compound is used. The semiconductor layer is composed of crystal planes arranged at an interval corresponding to the interplanar spacing (lattice spacing) of the crystal planes intersecting the surface of the single crystal body forming the boron phosphide-based semiconductor layer. ).
(3) The single crystal of the boron phosphide-based semiconductor crystal is a monomer boron phosphide (boron monophosphi).
de) A boron phosphide-based semiconductor device as described in (1) or (2) above, which is made of a crystal.

The present invention also provides (4) the above-mentioned boron phosphide-based semiconductor layer on a {111} -Si single crystal substrate at a temperature of 950 ° C. or higher and 1100 ° C. or lower, and a metalorganic pyrolysis vapor phase epitaxy method. (MOCVD method), the growth rate is 20n / min
The method for manufacturing a boron phosphide-based semiconductor device according to any one of the above (1) to (3), characterized in that the boron phosphide-based semiconductor device is formed to have a thickness of m or more and 60 nm or less. (5) The boron phosphide-based semiconductor layer is replaced with {1
1125-Si single crystal substrate 1025 ° C or more 1075 ° C
Metalorganic pyrolysis vapor phase epitaxy (MO
The growth rate is 30 nm or more per minute and 40 n
The method for producing a boron phosphide-based semiconductor device according to (4) above, wherein the boron phosphide-based semiconductor device is formed with a thickness of m or less. Is.

The present invention also provides (6) a light emitting diode comprising the boron phosphide-based semiconductor device according to any one of (1) to (3) above. Is.

Further, according to the present invention, (7) a boron phosphide-based semiconductor crystal formed on a surface of a substrate made of silicon (Si) single crystal and having the same crystal plane as the crystal plane constituting the surface of the substrate In the boron phosphide-based semiconductor layer, the substrate is {111} -Si having a surface of {111} crystal face.
The boron phosphide-based semiconductor layer is made of a single crystal, and has a bottom surface composed of the {111} crystal planes of the boron phosphide-based semiconductor crystal arranged in parallel with the {111} crystal plane of the substrate, and {111}. It is composed of a polycrystalline layer in which a plurality of quadrangular pyramid-shaped boron phosphide-based semiconductor crystal single crystals are surrounded by a plane equivalent to the crystal plane, and the single crystal is further provided with <1
10> A boron phosphide-based semiconductor layer having a twin boundary surface inclined at an angle of 60 degrees with respect to the crystal direction. Is.

[0011]

BEST MODE FOR CARRYING OUT THE INVENTION In the present invention, a boron phosphide-based semiconductor layer has a Si single crystal substrate having a {111} crystal face as a surface (in this specification, described as a {111} -Si single crystal substrate). It can be suitably formed on top. Diamond
on) In the {111} crystal plane of the Si single crystal of the crystal structure type, silicon atoms are denser than in the {100} or {110} crystal plane. Therefore, the {111} -Si single crystal substrate has the advantage of being able to suppress the diffusion and permeation of the constituent elements of the boron phosphide-based semiconductor layer deposited thereon into the substrate, and is effective in forming a clear bonding interface. Play. In the conductive {111} -Si single crystal substrate, an ohmic electrode having positive or negative polarity or any polarity can be laid as a back electrode on the back surface, and for example, it is effective to easily configure a light emitting element. Can be raised. In particular, a conductive single crystal substrate having a low specific resistance (resistivity) of 1 milliohm (mΩ) or less, and more preferably 0.1 mΩ or less has a low forward voltage (so-called Vf). To contribute.
In addition, the LD that has excellent heat dissipation provides stable oscillation.
Is effective in configuring.

Preferably on the surface of the {111} -Si substrate
The boron phosphide-based semiconductor layer of the polycrystalline layer to be laminated is boron.
Containing (B) and phosphorus (P) as constituent elements, for example, B
_αAl_βGa_γIn_{1- α - β - γ}P_{1- δ}As_δLayer (0 <α
≦ 1, 0 ≦ β <1, 0 ≦ γ <1, 0 <α + β + γ ≦ 1,
0 ≦ δ <1). Also, for example, B_αAl_βGa_γ
In _{1- α - β - γ}P_{1- δ}N_δ(0 <α ≦ 1, 0 ≦ β <1,
0 ≦ γ <1, 0 <α + β + γ ≦ 1, 0 ≦ δ <1)
To achieve. Monomeric boron phosphide (boron monop)
The constituent element of phosphide (BP) is boron (B).
Only phosphorus (P), with less constituent elements than multi-element mixed crystals
It is particularly preferable because it has the advantage of easy film formation.
Yes. In addition, for example, metal organic pyrolysis vapor deposition (MOCV)
D) Depending on the means, the growth rate is 2 nm per minute or more and 30 nm
The following is defined as a group V element such as phosphorus and a group III element such as boron.
Raw material supply ratio (so-called V / III ratio) of 15 or more is 6
Boron phosphide grown as a range of 0 or less is prohibited at room temperature.
Wide bandgap (wid) with a band width of about 3 eV
e bandgap) semiconductor. Bandwidth like this
For example, a wide boron phosphide semiconductor layer is used in a light emitting device.
And can be used as a clad layer for the light emitting layer.
It

In the present invention, the boron phosphide-based semiconductor layer of the polycrystal layer is formed by assembling a single crystal body composed of a plurality of boron phosphide-based semiconductor crystals. The shape of the single crystal body forming the polycrystalline layer according to the present invention is schematically shown in FIG. {11
Each single crystal body 13 on the 1} -Si single crystal substrate 11 has a regular tetragonal pyramid 13b or a top portion of the regular tetragonal pyramid having a periphery equivalent to the {111} crystal plane of the boron phosphide-based semiconductor crystal. It has an outer shape of a quadrangular pyramid 13c having a {111} crystal face. The bottom surface 13a of each single crystal body 13 is {111}-
It is composed of a {111} crystal plane of a boron phosphide-based semiconductor crystal arranged parallel to the {111} crystal plane of the Si single crystal substrate.
The bottom surface 13a is a crystal surface that is grounded on the surface of the {111} -Si single crystal substrate 11.

As shown in the schematic plan view of FIG. 2, the polycrystalline layer of the present invention is formed by bonding the above-mentioned plurality of quadrangular pyramid-shaped single crystal bodies 13 to each other. The single crystal bodies 13 are connected to each other via the joint surface 16. Twins 15 are present inside each single crystal body 13. Since the directions in which the twin planes 14 included in each single crystal body 13 exist are not uniformly uniform, each single crystal body 13 is composed of the single crystal bodies 13 containing twins in different crystal directions. The boron phosphide-based semiconductor layer is referred to as a polycrystalline layer in the present invention. In the present invention, in particular, <110} of the {111} -Si single crystal forming the substrate is <110.
> A single crystal body 13 having twin planes regularly included in a direction of 60 degrees (°) with respect to the crystal direction is assembled to form a polycrystalline layer. The twin plane referred to here is specifically a plane equivalent to the {111} crystal plane of the boron phosphide-based semiconductor crystal. That is, {111}, {-1. -1. -1. },
{1. -1.1. } And other crystal planes. Further, the twin plane is characterized in that it is parallel to any {111} crystal plane of the boron phosphide-based semiconductor crystal forming the periphery of the quadrangular pyramid-shaped single crystal body 13. Due to the generation of twins 15 having the {111} crystal planes of the boron phosphide-based semiconductor crystal as twin planes 14, a mismit dislocation resulting from a lattice mismatch between the Si single crystal substrate and the boron phosphide-based semiconductor crystal It is possible to effectively suppress the occurrence and propagation of. In a boron phosphide-based semiconductor crystal, a twin crystal having a {111} crystal plane as a twin plane can be formed more stably and easily than a twin crystal having another crystal plane as a twin plane. . Therefore, if a polycrystal layer is formed by assembling single crystal bodies containing twins having the {111} crystal planes of the boron phosphide-based semiconductor crystal as twin planes, the propagation of misfit dislocations can be suppressed stably. Can be effective.

The presence of twins is known, for example, from the presence or absence of anomalous diffraction spots on an electron beam diffraction pattern (pattern) imaged by an electron beam diffraction technique (Kankyu Saka, “Crystal Electron Microscopy”, (November 25, 1997, Uchida Old Crane Farm, First Edition, pp. 111-113). Also,
The angle formed between the <110> crystal direction on the diffraction pattern and the diffraction spots caused by twinning on the diffraction pattern obtained by imaging the incident electron beam parallel to the <110> crystal direction of the boron phosphide-based semiconductor layer is <110>. The angle between the crystal direction and the twin can be known. By the way, twins are also a kind of stacking fault (st
acking fault) (see "Crystal Electron Microscopy", page 112, above).

In order to obtain a polycrystalline layer in which single crystals containing twin crystals according to the present invention are assembled, it is necessary to precisely control the conditions during film formation. In particular, a tetragonal pyramidal single crystal made of a boron phosphide-based semiconductor crystal containing twins having a {111} crystal plane as a twin plane is, for example, triethylboron ((C ₂ H ₅ ) ₃
B) / Phosphine (PH ₃ ) / Hydrogen (H ₂ ) is used as a raw material system by a normal pressure metalorganic pyrolysis vapor phase epitaxy method (MOCVD method) while precisely controlling the growth temperature. MO above
In the CVD method, a temperature range suitable for obtaining a boron phosphide-based semiconductor polycrystalline layer, particularly a monomer boron phosphide polycrystalline layer, is 950 ° C. or more and 1100 ° C. or less, and more preferably 1025 ° C. or less. It is in the range of 1075 ° C. A lower temperature of about 950 ° C. to about 1000 ° C. is suitable for forming the boron phosphide-based semiconductor polycrystalline layer containing indium (In). The boron phosphide-based semiconductor polycrystalline layer containing aluminum (Al) as a constituent element has a relatively high temperature of about 1050 ° C.
~ 1100 ° C is preferred. At a high temperature exceeding about 1200 ° C., boron phosphide multimers such as BP ₆ and B ₁₃ P ₂ are easily generated, which is inconvenient to obtain a compositionally homogeneous boron phosphide-based semiconductor layer.

In order to efficiently form a single crystal body containing twins, the growth rate is 20 nm / min to 60 min / min.
It is desirable to set it in the range of nm. For monomeric boron phosphide (BP), a growth rate of 30 nm to 40 nm per minute is particularly suitable. A single crystal grown at a rate of more than 60 nm has excellent crystallinity because a large amount of twin crystals (stacking faults) and the density of other crystal defects such as point defects and dislocations are rapidly increased. It is difficult to obtain a polycrystalline layer. On the contrary, when the growth rate is reduced, that is, when it takes a longer time to obtain a boron phosphide-based semiconductor layer having a desired layer thickness, the opportunity for the constituent element phosphorus (P) to volatilize during the growth increases. . Therefore, at a small growth rate of less than 20 nm / min, a chemical equivalence ratio imbalance between the constituent elements of the boron phosphide-based semiconductor layer suddenly occurs due to evaporation and volatilization of phosphorus (P). The boron phosphide-based compound semiconductor layer having a stoichiometrically imbalanced composition is not suitable for the polycrystalline layer according to the present invention because it contains a large amount of point defects.

The twin crystals contained in the single crystal body cause the propagation of misfit dislocations caused by the lattice mismatch between the Si single crystal of the substrate and the boron phosphide-based semiconductor forming the single crystal body. Has a suppressing effect. For example, S
Misfit dislocations generated from the bonding interface between the i substrate and the single crystal body are absorbed by twins inside the single crystal body,
It has the effect of suppressing upward propagation. As a result, the density of threading dislocations penetrating to the top of the single crystal body is reduced.

In order to obtain a single crystal body with few misfit dislocations, the technical means of providing a buffer layer between the Si single crystal substrate and the boron phosphide-based semiconductor layer is also effective. The buffer layer is preferably composed of an amorphous or polycrystalline boron phosphide-based compound semiconductor layer. The amorphous or polycrystalline buffer layer is effective in relaxing the lattice mismatch with the Si single crystal that forms the substrate and providing a boron phosphide-based semiconductor layer with a low density of crystal defects such as misfit dislocations. To do. Further, in particular, when the buffer layer is composed of a boron phosphide-based semiconductor, since boron and phosphorus act as “growth nuclei” for promoting growth, it is necessary to form a continuous boron phosphide-based semiconductor layer thereon. Produce an effect. When the buffer layer is composed of boron phosphide, the layer thickness is about 1 nm or more and 50 nm or less,
Further, it is preferable that the thickness is 2 nm or more and 15 nm or less.

The surface layer portion of the polycrystalline layer formed by assembling single crystal bodies containing twins has a small amount of misfito dislocations penetrating from the side of the Si single crystal substrate below and is a region having excellent crystallinity. . Therefore, a deposited layer having excellent crystallinity can be grown on the boron phosphide-based semiconductor polycrystalline layer having the structure of the present invention. In particular, a crystal composed of crystal planes in which the deposited layer is arranged at the same spacing as the lattice spacing of the crystal lattice intersecting the surface of the single crystal body of the boron phosphide-based semiconductor forming the surface of the polycrystalline layer. When the layer is used, it is possible to obtain an effect of obtaining a crystal layer having few misfit dislocations and excellent crystallinity. As shown schematically in FIG. 3, the single crystal {11
Low-order Miller index {hkl} planes intersecting the surface 17 made of 1} crystal planes include {110} and {100} crystal planes in addition to {111} where h = k = 1 = 1. The spacing (= d) in the {111} crystal plane surface of these {hkl} crystal plane single crystals is d (Å) = in the boron phosphide-based semiconductor crystal of cubic zinc blende crystal. a / {(h ² +
k ² + l ² ) ^1/2 · sin θ}. a (Å) is the lattice constant of the boron phosphide-based semiconductor crystal, and θ is {11
1} is the angle (°) formed by the crystal surface 17 and the crystal plane intersecting it. For example, on the surface of a boron phosphide (BP) polycrystal layer, {1 of the BP single crystal 13 constituting the surface is formed.
Hexagonal (1.0.11) that matches the lattice spacing (≈3.21Å) with the {110} crystal plane that intersects the 11} crystal plane at a right angle.
0.0. ) Wurtzite crystal type (Wurt)
Zite) gallium nitride / indium mixed crystal (Ga _0.94)
An example of depositing an In _0.06 N) crystal layer is given. Such a crystal layer having excellent crystallinity can be suitably used, for example, in a light emitting device as a light emitting layer that provides high intensity light emission.

By using the polycrystalline layer of the boron phosphide-based semiconductor according to the present invention, for example, an LED can be constructed as a boron phosphide-based semiconductor element. LEDs are, for example, p-type {11
1} -Si single crystal substrate and p-type boron phosphide (BP) polycrystalline layer according to the present invention grown on the substrate through an amorphous buffer layer containing boron (B) and phosphorus (P) And a n-type light emitting layer on the polycrystalline layer, and an n-type boron phosphide (BP) polycrystalline layer according to the present invention grown on the light emitting layer. A polycrystalline layer composed of a single crystal of boron phosphide having a bandgap of about 3 eV at room temperature can be used as a clad layer sandwiching a light emitting layer. The light emitting layer is a single layer provided with a well layer made of Ga _x In _{1 -X} N (0 ≦ X ≦ 1) or gallium phosphide nitride (GaN _1-Y P _Y : 0 <Y ≦ 1), or a single layer. It may be composed of a multiple quantum well structure. By the way, the barrier against the well layer (barri)
er) layer is aluminum gallium nitride (Al _X Ga _1-X)
N: 0 ≦ X ≦ 1) or GaN _1-Z P _Z (0 ≦ Z <1, Z <
Y) or the like. An n-type ohmic (Ohmi) layer is formed on the n-type boron phosphide polycrystal layer forming the surface layer of the above laminated structure.
c) An electrode is provided, and a p-type Si single crystal substrate is provided with a p
A pn junction type heterostructure LED can be constructed by arranging the ohmic ohmic electrodes.

In addition, an undoped and high resistance {111} -Si single crystal substrate and oxygen grown on the substrate through a polycrystalline buffer layer containing boron (B) and phosphorus (P) ( O) -doped high-resistance boron phosphide polycrystal layer, and high-purity n-type gallium nitride (Ga) on the polycrystal layer.
The heterojunction field effect transistor (FE) is formed from the laminated structure including the N) layer as an active layer (electron transit layer).
An electronic device such as T) can be configured. The FET has a Schottky junction type gate electrode on the active layer, and a source and a source on opposite sides of the gate electrode on the surface of an n-type contact layer laminated on the active layer. A drain ohmic electrode is provided and configured.

[0023]

The single crystal body containing a twin crystal of the boron phosphide-based semiconductor crystal of the present invention suppresses upward propagation of misfit dislocations due to lattice mismatch between the Si single crystal substrate and the boron phosphide-based semiconductor. Has the effect of

[0024]

EXAMPLES The present invention will be concretely described below by using an example in which an LED was produced from a laminated structure having a boron phosphide (BP) layer formed of a polycrystalline layer on a {111} -Si single crystal substrate. Explained.

FIG. 4 shows a schematic plan view of the LED 1B according to this embodiment. Further, FIG. 5 shows a schematic cross-sectional view of the LED 1B taken along the broken line XX ′ shown in FIG.

The laminated structure 1A used for the LED 1B is boron (B) -doped and is 2 ° off (of) from the p-type (111) plane.
The Si single crystal having the surface f) was formed as the substrate 101. On the substrate 101, triethyl boron ((C ₂ H ₅ )
₃ B) / phosphine (PH ₃ ) / hydrogen (H ₂ ) system normal pressure MO
A buffer layer 102 made of boron phosphide mainly composed of amorphous material was deposited in an as-grown state at 350 ° C. by the CVD method. The layer thickness of the buffer layer 102 was about 10 nm.

The above MOCV is formed on the surface of the buffer layer 102.
D from the polycrystalline layer at 1050 ° C using vapor phase growth means
Then, a p-type boron phosphide (BP) layer 103 is laminated. Success
The long speed was set to 40 nm / min. p-type boron phosphide layer 1
03 carrier concentration is 1 x 10 ¹⁹cm^-3And also layer
The thickness was about 400 nm. Chamber for p-type boron phosphide layer 103
The band gap at high temperature was about 3.0 eV.

A p-type boron phosphide layer 1 was obtained from a cross-sectional TEM image and an electron diffraction pattern using a transmission electron microscope (TEM).
The internal crystal structure of 03 was analyzed. FIG. 6 shows a copy of a diffraction pattern of the p-type boron phosphide layer 103 obtained by making an electron beam incident parallel to the <110> crystal direction of the Si single crystal substrate 101. As shown in FIG. 6, {111} of each single crystal body 103a forming the p-type boron phosphide layer 103 composed of a polycrystalline layer
The diffraction spots 19 originating from the crystal plane were located parallel to the <111> crystal direction and adjacent to the diffraction spots 20 originating from the (111) crystal face of the Si single crystal substrate 101. As a result, the single crystal body 103a has a surface roughness of <11
It was shown that the {111} crystal faces of boron phosphide were stacked in parallel with the 1> crystal direction. Further, as shown in the diffraction pattern of FIG. 6, <111 of Si single crystal of the substrate 101 is formed.
> Diffraction spots 21 from twins having a {111} crystal plane as a twin plane were also confirmed in the vicinity with the diffraction spots of the single crystal body 103a aligned in the crystal direction as the center of point symmetry. Than this,
It was confirmed that the single crystal body 103a contained a twin crystal having a {111} crystal plane as a twin crystal plane. From the position of the diffraction spots 21 caused by twinning, it was shown that the twinning plane exists in the direction of 60 degrees in the angle with respect to the <110> crystal direction of the BP crystal.

On the surface of the p-type boron phosphide layer 103, trimethylgallium ((CH ₃ ) ₃ Ga) / trimethylindium ((CH ₃ ) ₃ In / ammonia (NH ₃ ) / H ₂ system atmospheric pressure MOCVD method is used. , the layer thickness of the laminated light-emitting layer 104 made of hexagonal n-type gallium indium nitride crystallization (Ga _{0. 90} in _0.10 n) at 850 ° C.. emitting layer 104 is about 10
nm.

An undoped n-type boron phosphide layer 105 made of a polycrystalline layer was laminated on the surface of the light emitting layer 104. The n-type boron phosphide layer 105 was deposited at 1050 ° C. using the MOCVD vapor phase growth means described above. The growth rate was set to 30 nm / min. n-type boron phosphide layer 105
Is a regular tetrahedral single crystal 105 composed of the (111) crystal plane of BP, like the p-type boron phosphide layer 103.
It is composed of the aggregate of a. The carrier concentration of the n-type boron phosphide layer was 8 × 10 ¹⁸ cm ^−3, and the layer thickness was about 300 nm. The band gap of the n-type boron phosphide layer 105 at room temperature was about 3.0 eV.

From the electron diffraction pattern, the n-type boron phosphide layer 1
The {111} crystal face of each single crystal body 105a forming
They were arranged in parallel with the <111> crystal direction of the (111) -Si single crystal substrate 101. In addition, it was confirmed that twin crystals having a {111} crystal plane of the BP crystal as a twin plane were present inside the single crystal body 105a. Twin plane is <110> of BP crystal
It was present in a direction of 60 degrees with respect to the crystal direction.

P at which the room temperature bandgap is approximately 3.0 eV
-Type boron phosphide layer 103 and n-type boron phosphide layer 105,
A light emitting layer 1 made of a material having the same lattice spacing
04 to form a light emitting portion 106 having a pn junction double hetero (DH) structure.

At the center of the surface of the n-type boron phosphide layer 105, a circular n-type ohmic electrode 107 also serving as a pedestal electrode is formed.
Was placed. The n-type ohmic electrode 107 is gold (Au)
A multilayer structure in which vacuum-deposited films of germanium (Ge) alloy / nickel (Ni) / gold are stacked. The diameter of the n-type ohmic electrode 107 was about 120 μm. In addition, on the substantially entire back surface of the p-type Si single crystal substrate 101,
The LED 1B was constructed by arranging the p-type ohmic electrode 108. The p-type ohmic electrode 108 was composed of an aluminum (Al) vacuum deposition film. Si single crystal substrate 10
Cut 1 in the direction parallel and perpendicular to the [211] direction,
A square LED 1B having a side of about 300 μm was used.

After connecting a gold (Au) wire to the n-type ohmic electrode 107, a forward working current of 20 milliamperes (mA) is passed between the n-type ohmic electrode 107 and the p-type ohmic electrode 108 to emit light. The characteristics were investigated. The emission center wavelength was about 420 nm. The full width at half maximum (FWHM) of the emission spectrum was 32 nm. In the present invention,
P-type boron phosphide layer 103 having a low density of misfit dislocations
Since the light emitting layer 104 is formed using as a base layer, a non-light emitting dark line is formed in the light emitting region.
(Yonezu, Hiroo, "Optical Communication Device Engineering-Light-Emitting / Light-Receiving Device"
(May 20, 1995, Engineering Book Co., Ltd. 5th edition, 15
(See pages 5 to 156) was not visually recognized, and light emission of approximately uniform intensity was provided from the entire surface of the light emitting region. Therefore, the luminance in a chip state measured by using a general integrating sphere is 8 millicandelas (mcd), and an LED with high emission intensity is provided. In addition, LED1
In the current-voltage (IV) characteristic of B, no local breakdown voltage failure (local breakdown) due to the influence of dislocation was observed, and from the configuration of the present invention, good pn junction characteristics (rectifying property) were obtained. It is shown that a pn junction type light emitting unit 106 exhibiting The forward voltage (so-called Vf) obtained from the IV characteristic is 3.6 V (forward current = 20).
mA, and the reverse voltage is 6 V (reverse current = 10
μA) and a high withstand voltage LED is provided.

[0035]

INDUSTRIAL APPLICABILITY According to the present invention, a twin phosphide capable of absorbing misfit dislocations and suppressing the propagation of dislocations in a boron phosphide-based semiconductor layer provided on a Si single crystal substrate whose surface is a {111} -crystal plane. Since it is composed of a polycrystal layer in which single crystal bodies containing is included, it is possible to form a boron phosphide-based semiconductor layer having low dislocation density and excellent crystallinity. There is an effect that a boron phosphide-based semiconductor light emitting device, for example, a boron phosphide-based semiconductor light emitting device excellent in light emission intensity, rectifying property, and pressure resistance can be provided.

[Brief description of drawings]

FIG. 1 is a schematic view showing a shape of a single crystal body forming a polycrystalline layer according to the present invention.

FIG. 2 is a schematic plan view showing the structure of a polycrystalline layer according to the present invention.

FIG. 3 shows the boron phosphide-based semiconductor layer according to the present invention {11.
It is a schematic diagram showing the crystal plane which intersects a 1} crystal plane.

FIG. 4 is a schematic plan view of an LED according to an example of the present invention.

5 is a schematic cross-sectional view of the LED taken along the broken line XX ′ of FIG.

FIG. 6 is a copy of an electron diffraction pattern of a boron phosphide layer according to an example of the present invention.

[Explanation of symbols]

1A laminated structure 1B LED 11 Si single crystal substrate 12 Boron phosphide-based semiconductor polycrystalline layer 13 Single crystal 13a Bottom surface of single crystal body 14 twin planes 15 twins 16 Bonding surface of single crystal 17 {111} crystal face of single crystal 18 {hkl} plane 19 Boron phosphide single crystal diffraction spot 20 Si single crystal substrate diffraction spot 21 twinned diffraction spot 101 Si single crystal substrate 102 buffer layer 103 p-type boron phosphide layer 103a single crystal 104 light emitting layer 105 n-type boron phosphide layer 105a single crystal 106 light emitting unit 107 n-type ohmic electrode 108 p-type ohmic electrode

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Claims (7)

[Claims] 1. A phosphor made of a substrate made of silicon (Si) single crystal and a boron phosphide-based semiconductor crystal formed on the surface of the substrate and having the same crystal plane as the crystal plane constituting the surface of the substrate. In a boron phosphide-based semiconductor device including a boron phosphide-based semiconductor layer, the substrate comprises a {111} -Si single crystal having a surface of {111} crystal face, and the boron phosphide-based semiconductor The layer has a plurality of bases each having a bottom surface composed of {111} crystal planes of a boron phosphide-based semiconductor crystal arranged parallel to the {111} crystal planes of the substrate and surrounded by a plane equivalent to the {111} crystal planes. Of a quadrangular pyramid-shaped boron phosphide-based semiconductor crystal, which is composed of a polycrystalline layer in which the single crystals are tilted at an angle of 60 degrees with respect to the <110> crystal direction of the substrate. Boron phosphide-based semiconductor element characterized by having twin boundaries . 2. III- on the boron phosphide-based semiconductor layer
It has a heterojunction formed by stacking group V compound semiconductor layers, and the group III-V compound semiconductor layer has a crystal plane intersecting the surface of a single crystal body forming a boron phosphide-based semiconductor layer. 2. The boron phosphide-based semiconductor device according to claim 1, wherein the boron phosphide-based semiconductor device is composed of crystal planes arranged at intervals corresponding to the interplanar spacing (lattice spacing). 3. A single crystal of the boron phosphide-based semiconductor crystal is a monomeric boron phosphide (boron monopho).
A sphere) crystal.
Alternatively, the boron phosphide-based semiconductor device according to item 2. 4. The boron phosphide-based semiconductor layer is {111}
On a -Si single crystal substrate at a temperature of 950 ° C or higher and 1100 ° C or lower, a metalorganic thermal decomposition vapor deposition method (MOCVD).
4. The method for producing a boron phosphide-based semiconductor device according to claim 1, wherein the growth rate is 20 nm or more and 60 nm or less per minute by the method). 5. The boron phosphide-based semiconductor layer is {111}
On a -Si single crystal substrate at a temperature of 1025 ° C or higher and 1075 ° C or lower, a metalorganic thermal decomposition vapor deposition method (MOCVD).
5. The method for producing a boron phosphide-based semiconductor device according to claim 4, wherein the growth rate is 30 nm or more and 40 nm or less per minute. 6. A light emitting diode comprising the boron phosphide-based semiconductor device according to claim 1. 7. A boron phosphide-based semiconductor formed of a boron phosphide-based semiconductor crystal, which is formed on the surface of a substrate made of silicon (Si) single crystal and has the same crystal plane as the crystal plane constituting the surface of the substrate. In the layer, the substrate has a surface of {11
The boron phosphide-based semiconductor layer is made of a {111} -Si single crystal having a 1} crystal face, and the boron phosphide-based semiconductor layer is arranged in parallel to the {111} crystal face of the substrate.
It is composed of a polycrystal layer which has a bottom surface composed of crystal planes and is surrounded by a plane equivalent to a {111} crystal plane, and which is an aggregate of a plurality of quadrangular pyramidal boron phosphide-based semiconductor crystal single crystals. ,
Further, the boron phosphide-based semiconductor layer, wherein the single crystal body has a twin boundary surface inclined at an angle of 60 degrees with respect to the <110> crystal direction of the substrate.