JP3639275B2 - Method for manufacturing p-type boron phosphide semiconductor layer, compound semiconductor device, and light emitting diode - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a method of manufacturing a low-resistance p-type boron phosphide semiconductor layer, and a compound semiconductor device and a light-emitting diode each including the p-type boron phosphide semiconductor layer obtained by this manufacturing method.
[0002]
[Prior art]
Monomeric boron phosphide (chemical formula: BP) is known as one of group III-V compound semiconductors (see Non-Patent Document 1). Conventionally, a boron phosphide layer is formed by a halogen method (see Non-Patent Document 2), a hydride method (see Non-Patent Document 3), or a metal organic chemical vapor deposition (MOCVD) method (Patent Document 2). And vapor phase growth means such as chemical beam deposition (see Non-Patent Document 4). For example, in the hydride method, diborane (molecular formula: B ₂ H ₆ ) As a boron raw material and phosphine (molecular formula: PH) ₃ ) Is used as a phosphorus raw material, and a boron phosphide layer is vapor-phase grown (see Non-Patent Document 3). In the MOCVD method, triethylboron (molecular formula: (C ₂ H ₅ ) ₃ B) is a boron raw material, and phosphine (PH ₃ ) As a phosphorus raw material (see Patent Document 2).
[0003]
In the formation of the boron phosphide layer by the hydride method, a p-type boron phosphide layer is formed if the concentration ratio of the phosphorus material to the boron material supplied to the vapor phase growth region, that is, the so-called V / III ratio is set low. (See Non-Patent Document 5). Further, in the MOCVD method, boron phosphide has a large effective mass of electrons, so that it is said that a p-type conductive layer can be formed more easily than an n-type conductive layer (patent). Reference 1). In addition, according to the MOCVD method, p-type phosphorus can be formed by intentionally adding a group II element in the periodic table of elements such as zinc (element symbol: Zn) and magnesium (element symbol: Mg). It is said that a boron fluoride layer is formed (see Patent Document 2).
[0004]
[Patent Document 1]
JP-A-2-288388
[Patent Document 2]
US Pat. No. 6,069,021
[Non-Patent Document 1]
P. POPPER, "Boron Phosphide, a III-V Compound of Zinc-Blende Structure", Nature, 4569, May 25, 1957, (UK), p. 1075
[Non-Patent Document 2]
TL CHU, “Crystals and Epitaxial Layers of Boron Phosphide”, Journal of Applied Physics, Volume 42, No. 1, January 1971, (US), p. 420-424
[Non-Patent Document 3]
K. SHOHNO, “EPITAXIAL GROWTH OF BP COMPOUNDS ON Si SUBSTRATES USING THE B ₂ H ₆ -PH ₃ -H ₂ SYSTEM ”, Journal of Crystal Growth, 24/25, 1974, (Netherlands), p. 193-196.
[Non-Patent Document 4]
Wai Kumashiro, “Preparation and Electrical Properties of Boron and Boron Phosphide Films Obtained by Gas Source Molecula r Beam Deposition”, Journal of Solid State Chemistry, Vol. 133, 1997, (USA) , P. 269-272
[Non-Patent Document 5]
Shono Katsufusa, “Semiconductor Technology (above)”, 9th edition, June 25, 1992, The University of Tokyo Press, p. 76-77
[0005]
[Problems to be solved by the invention]
However, for example, in the conventional technique in which the p-type boron phosphide layer is formed by the hydride method, it is necessary to set the V / III ratio to a low ratio. _n There is a problem that boron multimers such as P (7 ≦ n ≦ 10) are formed (see Non-Patent Document 5).
On the other hand, in the vapor phase growth method such as MOCVD, the p-type boron phosphide layer is generally formed at a high temperature exceeding 1000 ° C. For this reason, volatilization of boron and phosphorus constituting the boron phosphide layer at a high temperature becomes remarkable, and a p-type boron nitride layer having a good surface state has not been obtained. In addition, when volatilization of phosphorus is more intense than boron, p-type conductivity is lost, and a high resistance boron phosphide layer having a deteriorated surface state is formed.
[0006]
The present invention has been made to overcome the above-mentioned drawbacks of the prior art, avoids deterioration of the surface state due to volatilization of boron or the like in vapor phase growth at high temperature, and has high resistance or conductivity type n. The present invention provides a method capable of stably forming a low-resistance p-type boron phosphide layer (p-type boron phosphide semiconductor layer) while preventing inversion to the shape, and forming the low-resistance p-type boron phosphide layer An object of the present invention is to provide a compound semiconductor element and a light emitting diode using a layer (p-type boron phosphide semiconductor layer).
[0007]
[Means for Solving the Problems]
That is, in the method (1) for producing a p-type boron phosphide semiconductor layer of the present invention, a boron phosphide (BP) semiconductor layer exhibiting p-type conductivity is formed on a crystal substrate or a crystal layer, and boron (B) is used. In a method for producing a p-type boron phosphide semiconductor layer formed by vapor phase growth using a compound containing phosphorus and a compound containing phosphorus (P) as raw materials, the crystal substrate or crystal layer is formed at 750 ° C. or higher and 1200 ° C. or lower. An amorphous layer rich in boron with respect to phosphorus is formed by a vapor phase growth method with the ratio of the concentration supplied to the vapor phase growth region of the phosphorus material with respect to the boron material as the first ratio at the first temperature of Then, the p-type boron phosphide semiconductor layer is formed on the formed amorphous layer at a second temperature higher than 750 ° C. and lower than the first temperature at a second ratio larger than the first ratio. It is characterized by forming.
Further, in the method (2) for producing a p-type boron phosphide semiconductor layer of the present invention, silicon (Si) is added while forming the p-type boron phosphide semiconductor layer on the amorphous layer. It is characterized by performing vapor phase growth.
Moreover, in the manufacturing method (3) of the p-type boron phosphide semiconductor layer of the present invention, the concentration of silicon atoms in the p-type boron phosphide semiconductor layer obtained in the manufacturing method of (2) is 1 × 10. ¹⁹ cm ^-3 1 × 10 ²⁰ cm ^-3 A p-type boron phosphide semiconductor layer is vapor-grown and formed on the amorphous layer so as to be in the following range.
In addition, the method (4) for producing a p-type boron phosphide semiconductor layer according to the present invention is characterized in that, in the above production method, the first ratio is 5 or more and 50 or less.
Moreover, in the manufacturing method (5) of the p-type boron phosphide semiconductor layer of the present invention, in the manufacturing method, the second ratio is set to 1 × 10 6. ³ 1 × 10 ⁴ It is characterized by the following.
Moreover, in the manufacturing method (6) of the p-type boron phosphide semiconductor layer of the present invention, the thickness of the amorphous layer is 2 nm or more and 50 nm or less in the manufacturing method.
[0008]
The compound semiconductor element (7) of the present invention is characterized by including a p-type boron phosphide semiconductor layer formed by the manufacturing method described in any one of (1) to (6) above.
In the compound semiconductor device (8) of the present invention, the resistivity of the p-type boron phosphide semiconductor layer at room temperature is 5 × 10 5. ^-2 It is characterized by being less than ohm · cm [Ω · cm].
In the compound semiconductor device (9) of the present invention, the resistivity of the p-type boron phosphide semiconductor layer at room temperature is 1 × 10 5. ^-2 It is characterized by being less than ohm · cm [Ω · cm].
The compound semiconductor device (10) of the present invention is characterized in that any one of the compound semiconductor devices (7) to (9) has a pn junction structure with the p-type boron phosphide semiconductor layer. Yes.
[0009]
In the light emitting diode (11) of the present invention, a p-type boron phosphide semiconductor layer formed by the manufacturing method according to any one of the above (1) to (6) is provided on the p layer side of the diode, A p-type ohmic electrode is connected to the p-type boron phosphide semiconductor layer.
The light emitting diode (12) of the present invention is characterized in that the light emitting diode (11) has a double heterojunction structure.
[0010]
DETAILED DESCRIPTION OF THE INVENTION
The present invention will be described in detail below.
In the present invention, a p-type boron phosphide layer (p-type boron phosphide semiconductor layer) is formed on a crystal substrate or a crystal layer. That is, it is deposited on a crystal substrate made of a single crystal to be described later, a metal film as a crystal layer formed on a general substrate, or a semiconductor layer (semiconductor crystal layer).
Specifically, as a crystal substrate or crystal layer, a III-V compound semiconductor single crystal such as gallium arsenide (chemical formula: GaAs), gallium phosphide (chemical formula: GaP), gallium nitride (chemical formula: GaN), sapphire ( α-Al ₂ O ₃ Single crystal) oxide single crystal, silicon (Si) single crystal (silicon), and group IV semiconductor single crystal such as cubic or hexagonal silicon carbide (chemical formula: SiC). In addition, crystal layers made of these materials, such as aluminum nitride, gallium, indium (Al _x Ga _y In _z N: 0 ≦ X, Y, Z ≦ 1, X + Y + Z = 1) Crystal layers can also be mentioned.
[0011]
The p-type boron phosphide semiconductor layer manufacturing method according to the present invention is characterized in that a p-type boron phosphide semiconductor layer is not directly deposited on the above crystal substrate or crystal layer as in the prior art, but an amorphous layer is formed. There is an intervening vapor phase growth. The amorphous layer to be formed is composed of a layer containing boron and phosphorus in order to avoid deterioration of the surface state due to vapor phase growth at a high temperature and to avoid high resistance. In particular, an amorphous layer containing boron stoichiometrically rich with respect to phosphorus is used. This makes it possible to form a p-type boron phosphide semiconductor layer that is excellent in surface state and low resistance, as will be described later.
[0012]
Such an amorphous layer containing boron stoichiometrically rich with respect to phosphorus has a temperature of 750 ° C. or higher and 1200 ° C. or lower, preferably 850 ° C. or higher and 1150 ° C. or lower. The ratio of the concentration (V / III ratio) supplied to the vapor phase growth region of the phosphorus raw material (Group V raw material) relative to the Group III raw material), that is, boron supplied to the region where the crystal layer is vapor grown (vapor phase growth region) It is efficiently obtained by setting the ratio of the phosphorus atom concentration to the atom concentration to 5 or more and 50 or less, and forming by the vapor phase growth method. Here, the vapor phase growth temperature is defined as the first temperature, and the concentration ratio of the raw material set and supplied here is defined as the first ratio.
A V / III ratio higher than the above range is not preferable because a polycrystalline layer is easily formed.
Further, when a boron raw material containing only boron atoms and a phosphorus raw material containing only phosphorus atoms are used, the V / III ratio is the ratio of the flow rates of both raw materials supplied to the vapor phase growth region per unit time. Given in.
[0013]
The thickness of the amorphous layer to be formed is preferably 2 nm or more and 50 nm or less. An ultra-thin film of less than 2 nm does not sufficiently cover the surface of the crystal substrate or crystal layer on which an amorphous layer is to be provided, which is inconvenient for obtaining a continuous p-type boron phosphide semiconductor layer. Because there is a fear. On the other hand, if the layer thickness exceeds 50 nm, it becomes easy to become a polycrystalline layer, and it becomes difficult to obtain an amorphous layer.
[0014]
The thickness of such an amorphous layer can be measured by, for example, observing the cross section of the amorphous layer with a cross-sectional TEM (transmission electron microscope) technique. Further, polycrystal or amorphous can be discriminated by electron beam diffraction means or X-ray diffraction means using a transmission electron microscope or the like. As for the stoichiometric composition of boron and phosphorus in the amorphous layer containing boron and phosphorus, for example, general secondary ion mass spectrometry (English abbreviation: SIMS) and Auger It can be known from the quantitative results obtained by elemental analysis such as electron spectroscopy (abbreviation: AES).
[0015]
The p-type boron phosphide semiconductor layer formed by bonding to this amorphous layer is vapor-phase grown at a second temperature which is not higher than the first temperature and not lower than 750 ° C. Specifically, after an amorphous layer is vapor-phase grown at 1050 ° C. on the surface of a {111} -silicon (Si) single crystal substrate, p-type boron phosphide is grown on the amorphous layer at 850 ° C. A preferred example is a method in which the semiconductor layer is vapor-phase grown.
When the p-type boron phosphide semiconductor layer is vapor-phase grown on the amorphous layer after the amorphous layer is formed at the first temperature, the p-type boron phosphide semiconductor layer is formed at a temperature exceeding the first temperature. When vapor-phase growth of p-type boron phosphide semiconductor layer at high temperature, boron and phosphorus are disproportionately volatilized from the amorphous layer, and the amorphous layer is not rich in boron. This is not preferable.
In forming the p-type boron phosphide semiconductor layer, the V / III ratio, that is, the ratio of the concentration supplied to the vapor phase growth region of the phosphorus material with respect to the boron material is made larger than the first ratio. This is because if a p-type boron phosphide semiconductor layer is formed at the same ratio as the first ratio, a single crystal p-type boron phosphide semiconductor layer cannot be obtained. A preferred range for the second ratio is 1 × 10 ³ 1 × 10 ⁴ It is as follows.
[0016]
As described above, on the amorphous layer obtained by vapor phase growth at the preferred first temperature and the first V / III ratio, the resistivity at room temperature (= specific resistance) is 5 × even in the undoped state. 10 ^-2 A p-type boron phosphide semiconductor layer having a low resistance of Ω · cm or less can be obtained.
Furthermore, according to the present invention, a p-type boron phosphide layer can be stably formed by adding silicon (Si) as an impurity together with boron and phosphorus raw materials during vapor phase growth of the p-type boron phosphide semiconductor layer. Vapor phase growth is used. Thus, by adding silicon, the resistivity at room temperature is 1 × 10 ^-2 A p-type boron phosphide semiconductor layer having a low resistivity of Ω · cm or less can be vapor-phase grown.
[0017]
As a doping source of silicon, silane (molecular formula: SiH ₄ ) And disilane (molecular formula: Si ₂ H ₆ ) Can be used. Regarding the concentration of silicon to be doped, the concentration of silicon atoms in the p-type boron phosphide semiconductor layer is 1 × 10 5. ¹⁹ cm ^-3 1 × 10 ²⁰ cm ^-3 The most preferable range is as follows. The concentration of silicon atoms inside the p-type boron phosphide semiconductor layer can be quantified by general secondary ion mass spectrometry (SIMS), Auger electron spectroscopy (AES), or the like. A p-type boron phosphide semiconductor layer can also be obtained by adding beryllium (element symbol: Be) belonging to Group II of the periodic table of elements together with silicon (Si). However, it is not preferable to use an element that combines with boron such as magnesium (element symbol: Mg) as a group II element that is doped simultaneously with silicon to produce a volatile boron compound.
[0018]
Since the p-type boron phosphide semiconductor layer formed according to the present invention has a low resistance and an excellent surface state, it can be effectively used as a p-type conductive layer for constituting various compound semiconductor elements. .
Further, although this p-type boron phosphide semiconductor layer contains stacking faults or twins, there are almost no misfit dislocations. Therefore, the p-type boron phosphide semiconductor layer can be used, for example, as a constituent layer of a pn junction structure having excellent breakdown voltage characteristics. If this pn junction structure is used, a compound semiconductor light emitting diode (LED) or a current confining type laser diode (LD) excellent in rectification can be formed.
Moreover, since the p-type boron phosphide semiconductor layer according to the present invention has a low misfit dislocation density, the p-type boron phosphide semiconductor layer is effective in constructing a pn junction solar cell with little leakage current.
[0019]
(Function)
Since an amorphous layer is formed so as to contain boron stoichiometrically rich with respect to phosphorus, it is vapor-phase grown at a higher temperature by interposing it, thereby forming a p-type boron phosphide semiconductor layer. The amorphous layer suppresses deterioration of the surface state of the obtained p-type boron phosphide semiconductor layer and avoids high resistance so that it becomes a low-resistance p-type boron phosphide semiconductor layer. Act on.
[0020]
Further, when vapor-phase-growing a p-type boron phosphide semiconductor layer on an amorphous layer containing boron and phosphorus, silicon is added together with boron and phosphorus raw materials. The boron semiconductor layer has a low resistivity with a stable resistivity.
[0021]
【Example】
(First embodiment)
The contents of the present invention will be specifically described by taking as an example a case where a p-type boron phosphide semiconductor layer is vapor-phase grown on a sapphire substrate by MOCVD. In FIG. 1, the cross-sectional schematic diagram of the laminated structure 10 as described in a present Example is shown.
[0022]
The substrate 101 constituting the laminated structure 10 has {0.0.0.1. } A sapphire single crystal having a crystal plane as a surface was used. On the (0.0.0.1.) Surface of the substrate 101, triethylboron ((C ₂ H ₅ ) ₃ B) / phosphine (PH ₃ ) The amorphous layer 102 was grown at 1025 ° C. by an atmospheric pressure MOCVD method using a raw material system. The amorphous layer 102 containing boron and phosphorus has a V / III ratio (= PH ₃ / (C ₂ H ₅ ) ₃ B) was grown as 16. The layer thickness of the amorphous layer 102 was 20 nm. In elemental analysis based on general SIMS, phosphorus ions ( ¹⁵ P ⁺ ) Boron ion () ⁵ B ⁺ ) Strength ratio was estimated to be about 1.01. That is, it was determined that the concentration of boron atoms was 1% higher than the atomic concentration of phosphorus.
[0023]
Next, on the amorphous layer 102, (C ₂ H ₅ ) ₃ B / PH ₃ / H ₂ An undoped boron phosphide crystal layer (p-type boron phosphide semiconductor layer) 103 was deposited at 850 ° C. by atmospheric pressure MOCVD using a raw material system. The layer thickness was 350 nm. The obtained p-type boron phosphide semiconductor layer 103 has a carrier concentration of 2 × 10 4 according to a general Hall effect measurement. ¹⁹ cm ^-3 And the resistivity is 2 × 10 ^-2 The p-type layer was Ω · cm. The p-type boron phosphide semiconductor layer 103 was a continuous film, and the surface thereof was flat.
[0024]
The crystallographic structures inside the amorphous layer 102 and the p-type boron phosphide semiconductor layer 103 were investigated by a cross-sectional TEM technique. From the limited-field electron diffraction method, only a halo diffraction pattern is obtained from the boron-rich amorphous layer provided on the surface of the (0.0.0.1.)-Sapphire substrate 101. It was.
The p-type boron phosphide semiconductor layer 103 was a single crystal layer. Further, the high-resolution bright-field contrast image shows that there are stacking faults or twinnings in the amorphous layer 102 and the p-type boron phosphide semiconductor layer 103 on the sapphire substrate 101. The presence of misfit dislocations was hardly observed.
[0025]
(Second embodiment)
The content of the present invention will be specifically described by taking as an example a case where a compound semiconductor LED is configured using a low-resistance p-type boron phosphide semiconductor layer that is vapor-phase grown while doping silicon. In FIG. 2, the cross-sectional schematic diagram of LED11 as described in a present Example is shown. In addition, about the component same as the element described in FIG. 1, the same code | symbol is attached | subjected and it shows in FIG.
[0026]
First, on the (0.0.0.1.)-Sapphire substrate 101, (CH ₃ ) ₃ Ga / NH ₃ / H ₂ A lower cladding layer 104 made of an n-type gallium nitride layer was deposited at 1050 ° C. by an atmospheric pressure MOCVD method using a raw material system. Carrier concentration is 3 × 10 ¹⁸ cm ^-3 And the layer thickness is 2.8 × 10 ^-4 cm.
Next, on the n-type lower cladding layer 104, (CH ₃ ) ₃ Ga / trimethylindium (molecular formula: (CH ₃ ) ₃ In) / NH ₃ / H ₂ According to atmospheric pressure MOCVD method using raw material system, Ga _0.90 In _0.10 The light emitting layer 105 made of N was vapor grown at 850 ° C. The layer thickness is 80 nm, and the carrier concentration is about 3 × 10. ¹⁸ cm ^-3 It was.
Next, the above (CH ₃ ) ₃ Ga / NH ₃ / H ₂ The upper cladding layer 106 made of p-type GaN was vapor grown at 1025 ° C. by atmospheric pressure MOCVD using a raw material system. The layer thickness of the p-type upper cladding layer 106 was 100 nm. The carrier concentration of the GaN layer forming the p-type upper cladding layer 106 is about 4 × 10 ¹⁷ cm ^-3 It was.
[0027]
After the vapor phase growth of the p-type upper cladding layer 106 was completed, the temperature of the sapphire substrate 101 was lowered to set the first temperature in the present invention to 1025 ° C.
Next, (C ₂ H ₅ ) ₃ B / PH ₃ / H ₂ An amorphous layer 102 containing boron and phosphorus was deposited by an atmospheric pressure MOCVD method using a raw material system. V / III ratio (= PH) as the first ratio in the present invention ₃ / (C ₂ H ₅ ) ₃ B) was set to 8. The layer thickness of the undoped amorphous layer was 10 nm.
[0028]
After the vapor phase growth of the amorphous layer 102 is completed, a boron raw material ((C ₂ H ₅ ) ₃ B) stop supplying while PH ₃ The second temperature in the present invention was set to 850 ° C. by lowering the temperature of the sapphire substrate 101 while continuing the distribution (supply).
Next, (C ₂ H ₅ ) ₃ B / PH ₃ / H ₂ The p-type boron phosphide crystal layer 103 doped with silicon (Si) was vapor-phase grown by an atmospheric pressure MOCVD method using a raw material system. Disilane (Si ₂ H ₆ : 10 volume parts per million (Vol. Ppm))-hydrogen (H ₂ ) A mixed gas was used.
[0029]
Silicon has a silicon atom concentration in the p-type boron phosphide crystal layer 103 of about 1 × 10 6. ¹⁹ Atom / cm ³ It added so that it might become. The V / III ratio during growth, that is, the second ratio in the present invention was 1250. The carrier concentration of the obtained p-type boron phosphide crystal layer 103 is 1 × 10 ¹⁹ cm ^-3 And the layer thickness was 100 nm. Also, the resistivity at room temperature is 5 × 10 ^-3 It was Ω · cm. Since the p-type boron phosphide semiconductor layer 103 was grown using the amorphous layer 102 as an underlayer, the p-type boron phosphide semiconductor layer 103 became a continuous layer having a flat surface without cracks.
Vapor phase growth of the p-type boron phosphide crystal layer 103 was completed by stopping the supply of the boron raw material to the vapor phase growth region. However, after that, until the temperature of the sapphire substrate 101 drops to about 600 ° C., PH ₃ Was continuously distributed. Then PH ₃ The flow of water was also stopped and the temperature dropped naturally to a temperature near room temperature.
[0030]
After cooling, the crystallographic structures of the p-type upper cladding layer 106, the amorphous layer 102, and the silicon-doped p-type boron phosphide crystal layer 103 were investigated by a cross-sectional TEM technique. From the limited-field electron diffraction technique, the p-type upper cladding layer 106 is composed of a (0.0.0.1.)-GaN layer, and the p-type boron phosphide crystal layer 103 is composed of a {111} -crystal layer. Turned out to be. Further, from the high-resolution bright-field contrast image, about 1 × 10 10 propagated mainly from the vicinity of the junction interface between the sapphire substrate 101 and the lower cladding layer 104 in the upper cladding layer 106. ¹⁰ cm ^-2 A large amount of misfit dislocations was observed. However, most of these dislocations are blocked at the bonding interface with the amorphous layer 102, and are prevented from entering the amorphous layer 102 and the boron phosphide layer 103. For this reason, almost no dislocation was observed in the amorphous layer 102 and the silicon-doped p-type boron phosphide semiconductor layer 103. On the other hand, stacking faults or twins along the {111} -crystal orientation were present inside the silicon-doped p-type boron phosphide semiconductor layer 103. It was determined that these stacking faults or twins absorbed dislocations, and the propagation of dislocations from the {0001} -GaN layer of the upper cladding layer 106 was suppressed.
[0031]
Using p-type boron phosphide crystal layer 103, amorphous layer 102, upper cladding layer 106, and n-type light emitting layer 105 in the region where n-type ohmic electrode 107 is to be formed using selective patterning technology and plasma etching technology And removed. As a result, the surface of the n-type lower cladding layer 104 was exposed.
Next, an n-type ohmic electrode 107 made of a gold / germanium alloy (Au 93 wt% / Ge 7 wt%) was disposed on the surface of the exposed n-type GaN layer. On the other hand, a p-type ohmic electrode 108 made of gold / beryllium alloy (Au 99 wt% / Be 1 wt%) was provided on the substantially central surface of the remaining p-type boron phosphide crystal layer 103. Thus, an LED 11 having a pn junction type DH structure (double hetero structure) was formed.
[0032]
An operating current of 20 milliamperes (mA) is passed in the forward direction between the n-type and p-type ohmic electrodes 107 and 108, and each side is about 3.5 × 10 ^-2 The light emission characteristics of the LED chip 11 cut into a square of cm were confirmed. The light emission characteristics obtained are summarized below.
(1) Luminous color: Blue purple
(2) Emission center wavelength: about 435 (nm)
(3) Brightness (chip state): about 8 (mcd)
(4) Forward voltage: Approximately 3.7 (V) (However, when the forward current is 20 mA)
(5) Reverse voltage: 11V (provided that the reverse current is 10 μA)
[0033]
Since the p-type ohmic electrode 108 is provided in contact with the p-type boron phosphide semiconductor layer 103 having a low resistivity and a low dislocation density, the input resistance is low and the lower p-type upper cladding layer 106 and the light emitting layer 105 are formed. Thus, the operating current can be diffused over a wide area of the light emitting layer 105 through the p-type upper cladding layer 105. For this reason, the near-field emission image of the LED 11 showed that light emission was brought about from substantially the entire surface of the light-emitting layer 105.
[0034]
【The invention's effect】
In accordance with the present invention, at a second temperature less than or equal to the first temperature, through an amorphous layer comprising boron and phosphorus vapor-grown at a first ratio at a first ratio, Since the p-type boron phosphide semiconductor layer is vapor-phase grown at a second ratio equal to or higher than the first ratio, a p-type boron phosphide semiconductor layer having excellent surface condition and low resistivity is formed. Excellent effect is achieved.
[0035]
According to the present invention, when vapor-phase-growing the p-type boron phosphide semiconductor layer on the amorphous layer, silicon is doped together with boron and phosphorus sources, so that the resistivity at room temperature is obtained. 1 × 10 ^-2 An excellent effect is obtained in that a p-type boron phosphide semiconductor layer having a low resistance of Ω · cm or less can be stably formed.
[0036]
In addition, according to the compound semiconductor device of the present invention, by using the low-resistance p-type boron phosphide semiconductor layer obtained by the above-described manufacturing method, for example, a pn junction structure layer excellent in breakdown voltage characteristics It can be used as an industrially effective one.
Further, according to the light emitting diode of the present invention, the low resistance p-type boron phosphide semiconductor layer obtained by the above manufacturing method is used, and the p-type ohmic electrode is connected to the p-type ohmic electrode. It is low and good and is therefore very effective in the industry.
[Brief description of the drawings]
FIG. 1 is a schematic cross-sectional view of a laminated structure according to the present invention.
FIG. 2 is a schematic cross-sectional view of an LED according to the present invention.
[Explanation of symbols]
10 Laminated structure, 11 LED, 101 Crystal substrate, 102 Amorphous layer
103 p-type boron phosphide semiconductor layer, 104 lower cladding layer, 105 light emitting layer
106 upper cladding layer, 107 n-type ohmic electrode,
108 p-type ohmic electrode

Claims (12)

Production of a p-type boron phosphide semiconductor layer by forming a boron phosphide semiconductor layer exhibiting p-type conductivity on a crystal substrate or a crystal layer by vapor phase growth using a compound containing boron and a compound containing phosphorus as raw materials In the method,
Boron is phosphorus on the crystal substrate or crystal layer at a first temperature not lower than 750 ° C. and not higher than 1200 ° C., with the ratio of the concentration supplied to the vapor phase growth region of the phosphorus source with respect to the boron source being the first ratio. A rich amorphous layer is formed by vapor phase growth,
Thereafter, a p-type boron phosphide semiconductor layer is formed on the amorphous layer at a second temperature higher than the first ratio at a second temperature of 750 ° C. or higher and lower than the first temperature. A method for producing a p-type boron phosphide semiconductor layer, wherein: 2. The production of a p-type boron phosphide semiconductor layer according to claim 1, wherein when forming the p-type boron phosphide semiconductor layer on the amorphous layer, vapor phase growth is performed while adding silicon. Method. The p-type boron phosphide semiconductor layer is formed on the amorphous layer so that the concentration of silicon atoms is in the range of 1 × 10 ¹⁹ cm ⁻³ to 1 × 10 ²⁰ cm ^−3. 3. The method for producing a p-type boron phosphide semiconductor layer according to claim 2, wherein the boron phosphide semiconductor layer is formed by vapor phase growth. The method for producing a p-type boron phosphide semiconductor layer according to any one of claims 1 to 3, wherein the first ratio is 5 or more and 50 or less. 5. The method of manufacturing a p-type boron phosphide semiconductor layer according to claim 1, wherein the second ratio is 1 × 10 ³ or more and 1 × 10 ⁴ or less. 6. The method for producing a p-type boron phosphide semiconductor layer according to claim 1, wherein the amorphous layer has a thickness of 2 nm to 50 nm. A compound semiconductor device comprising a p-type boron phosphide semiconductor layer formed by the manufacturing method according to claim 1. 8. The compound semiconductor device according to claim 7, wherein the resistivity of the p-type boron phosphide semiconductor layer at room temperature is 5 × 10 ⁻² ohm · centimeter or less. 8. The compound semiconductor device according to claim 7, wherein the resistivity of the p-type boron phosphide semiconductor layer at room temperature is 1 × 10 ⁻² ohm · centimeter or less. The compound semiconductor device according to claim 7, further comprising a pn junction structure with the p-type boron phosphide semiconductor layer. A p-type boron phosphide semiconductor layer formed by the manufacturing method according to claim 1 is provided on the p-layer side of the diode, and a p-type ohmic electrode is provided on the p-type boron phosphide semiconductor layer. A light emitting diode characterized by being connected. 12. The light emitting diode according to claim 11, wherein the light emitting diode has a double heterojunction structure.

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