JP2005024827A - Semiconductor multilayered film reflection mirror and optical semiconductor device including the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a semiconductor multilayered film reflection mirror which is made of a material mild to an environment, in which refractive index difference between a high refractive index layer and a low refractive index layer is larger than 0.6, current can also be made to flow, and which can realize a planar optical device operating especially at 1,300nm band or at 1,550nm band being a communication wavelength band, and to provide an optical semiconductor device including the same. <P>SOLUTION: The semiconductor multilayered film reflection mirror is constituted by alternatively laminating a first layer of a fullerene film such as a C<SB>60</SB>fullerene film 6 and a second layer of a group IV semiconductor such as a Si film 4. Moreover the semiconductor multilayered film reflection mirror is constituted by forming the second layer of group II1 to V semiconductor such as a GaP film or of a fullerene film such as a C<SB>90</SB>fullerene film. The optical semiconductor device such as a wavelength variable filter, a face emission type laser, a photodiode or an optical modulator is constituted by using these semiconductor multilayered film reflection mirrors. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a semiconductor multilayer film reflecting mirror having fullerene and an optical semiconductor device including the same.
[0002]
[Prior art]
A conventional flag reflector having a semiconductor multilayer film structure is manufactured as a part of a reflector of a surface emitting laser by epitaxial growth by changing the Al composition of semiconductor AlGaAs. However, since the refractive index difference between AlAs and GaAs is about 0.6, about 20 pairs of a high refractive index layer and a low refractive index layer are required to obtain a reflectivity of 99%. There have been problems such as an increase in thickness and deterioration of the crystal state, high resistance, and a high light absorption ratio (for example, see Non-Patent Document 1 below).
[0003]
In some cases, an oxide was introduced to increase the difference in refractive index between the high-refractive index layer and the low-refractive index layer. However, since the oxide does not pass current, the manufacturing process is complicated, such as current injection from the side. (For example, see Non-Patent Document 2 below).
[0004]
In addition, since the reflecting mirror of the surface emitting laser is made of AlGaAs, GaInAsP, or the like, it contains a large amount of In and toxic As that have few resources (see Non-Patent Document 3 below).
[0005]
[Non-Patent Document 1]
K. Kurihara, et al. , V. Appl. Phys. 73 (1993) 21
[Non-Patent Document 2]
M.M. H. MacDougal, et al. , IEEE Photonics Technol. Lett. 8 (1996) 310
[Non-Patent Document 3]
Makita et al., Materials Science vol. 37, 2000, p-1
[0006]
[Problems to be solved by the invention]
In view of the above problems, the present invention is made of an environmentally friendly material, the refractive index difference between the high-refractive index layer and the low-refractive index layer is larger than 0.6, and can pass current, particularly in the communication wavelength band. It is an object to provide a semiconductor multilayer film reflecting mirror capable of realizing a planar optical device operating in a certain 1300 nm or 1550 nm band and an optical semiconductor device including the same.
[0007]
[Means for Solving the Problems]
The semiconductor multilayer film reflecting mirror according to the first aspect of the present invention for solving the above-mentioned problems is composed of a first layer (refractive index n0) made of fullerene (Cn1) and fullerene (Cn2) having a refractive index different from that of the first layer. The second layer (refractive index n1) is alternately and repeatedly stacked, and the thickness of the first layer is m0 · λ / where m0 is a positive integer with respect to the acting light (wavelength λ). (4 · n0), and the thickness of the second layer is m1 · λ / (4 · n1), where m1 is a positive integer.
[0008]
The semiconductor multilayer film reflecting mirror of the second invention is a first layer (refractive index n0) made of fullerene (Cn1) and a second layer made of a group IV semiconductor having a refractive index different from that of the first layer. (Refractive index n1) is alternately and repeatedly stacked, and with respect to the acting light (wavelength λ), the thickness of the first layer is m0 · λ / (4 · n0) where m0 is a positive integer. ), And the thickness of the second layer is m1 · λ / (4 · n1), where m1 is a positive integer.
[0009]
The semiconductor multilayer film reflecting mirror of the third invention is the semiconductor multilayer film reflecting mirror of the second invention, wherein the group IV semiconductor is Si.
[0010]
The semiconductor multilayer mirror according to the fourth aspect of the invention is a first layer (refractive index n0) made of fullerene (Cn1) and a second layer made of a II1-V group semiconductor having a refractive index different from that of the first layer. Of layers (refractive index n1) are alternately and repeatedly stacked,
For the acting light (wavelength λ), the thickness of the first layer is m0 · λ / (4 · n0), where m0 is a positive integer, and the thickness of the second layer is m1 as a positive integer. It is m1 * λ / (4 * n1).
[0011]
According to a fifth aspect of the semiconductor multilayer film reflecting mirror of the fourth aspect of the present invention, the III-V group semiconductor is GaP.
[0012]
Further, the semiconductor multilayer film reflector according to the sixth invention is characterized in that, in the semiconductor multilayer film reflector according to the fourth invention, the contents of As, Sb and In of the group III-V semiconductor are all 1% or less. To do.
[0013]
The semiconductor multilayer film reflecting mirror of the seventh invention is the semiconductor multilayer film reflecting mirror of the first invention, wherein each order of the first layer made of fullerene (Cn1) and the second layer made of fullerene (Cn2). n1 and n2 are both 60 or more and 200 or less.
[0014]
An eighth aspect of the semiconductor multilayer reflector according to the second aspect is the semiconductor multilayer reflector according to any one of the second to sixth aspects, wherein the order n1 of the first layer made of fullerene (Cn1) is 60 or more and 200 or less. It is characterized by being.
[0015]
The semiconductor multilayer mirror of the ninth invention is the semiconductor multilayer mirror of any of the first to eighth inventions, wherein both the first layer and the second layer are p-type or n-type. It is characterized by being doped with impurities.
[0016]
The semiconductor multilayer film reflector according to a tenth aspect of the present invention is the semiconductor multilayer film reflector according to any one of the first to ninth aspects of the present invention, by passing a current or applying a voltage, By changing the refractive index of the second layer, the wavelength that becomes the peak reflectance can be changed.
[0017]
An optical semiconductor device including the semiconductor multilayer reflector according to the eleventh aspect of the invention is an optical semiconductor device including the semiconductor multilayer reflector according to any of the first to ninth aspects, wherein the upper semiconductor multilayer reflector is provided. An intermediate layer has a vertical resonator structure composed of the lower semiconductor multilayer reflector, and a current is passed through the upper semiconductor multilayer reflector and the lower semiconductor multilayer reflector, or voltage The function of the wavelength tunable filter is provided by applying.
[0018]
An optical semiconductor device including the semiconductor multilayer reflector according to the twelfth aspect of the invention is an optical semiconductor device including the semiconductor multilayer reflector according to any of the first to ninth inventions, wherein at least one semiconductor multilayer reflector is provided. It has a vertical cavity structure constituted by having a mirror and a light emitting layer, and has a function of a surface emitting laser.
[0019]
An optical semiconductor device including the semiconductor multilayer reflector according to the thirteenth aspect of the present invention is the optical semiconductor device including the semiconductor multilayer reflector according to any of the first to ninth inventions, wherein at least one semiconductor multilayer reflector is provided. And a light receiving layer, and has a photodiode function.
[0020]
An optical semiconductor device including the semiconductor multilayer reflector according to the fourteenth aspect of the invention is an optical semiconductor device including the semiconductor multilayer reflector according to any of the first to ninth aspects, wherein at least one semiconductor multilayer reflector is provided. And a light modulation layer, and has a function of a light modulator.
[0021]
DETAILED DESCRIPTION OF THE INVENTION
[First Embodiment]
A first embodiment of the present invention will be described. In the first embodiment, a C ₆₀ fullerene film was deposited on a Si substrate using a K cell.
[0022]
1 shows a wavelength dispersion of the refractive index and the absorption coefficient of the C ₆₀ fullerene film. From Figure _{1, C 60} fullerene film, the absorption coefficient at 1300nm or 1550nm band communication wavelength region (extinction coefficient in the drawing) is small, it can be seen that transparent. Further, it can be seen from FIG. 1 that the C ₆₀ fullerene film has a very large refractive index difference with Si of about 1.5.
[0023]
From the hole measurement, the C ₆₀ fullerene film was an n-type semiconductor and showed a carrier concentration of 10 ¹⁰ cm ⁻³ .
[0024]
Further, a thin film of C ₈₄ and C ₉₀ was deposited on the Si substrate, and the refractive indexes of these C ₈₄ fullerene film and C ₉₀ fullerene film were measured. The refractive index of the C ₈₄ fullerene film and C ₉₀ fullerene film was 1550 nm. in the 3.0,3.4, _{respectively,} greater than the refractive index of the _{C 60} fullerene film, the refractive index difference was confirmed to be a refractive index difference of the GaAs / AlAs (0.6) or more.
[0025]
In the present invention, the order n (defined by n of Cn) of fullerene, which is a higher-order compound of carbon, is 60 or more and 200 or less.
[0026]
[Second Embodiment]
A second embodiment of the present invention will be described with reference to FIGS.
[0027]
When a resonator structure is manufactured using a semiconductor multilayer mirror, first, as shown in FIGS. 2A to 2C, an SiO ₂ film 3 and an Si film 4 are formed on an Si substrate 2. C ₆₀ and Al are vapor-deposited simultaneously on the Si film 4 of the n-type SOI substrate 1 and the n-type Si substrate 5 to form a C ₆₀ fullerene film 6. The reason why Al is co-deposited is to make the C ₆₀ fullerene film 6 conductive.
[0028]
Thereafter, as shown in FIG. 2 (e), and _{C 60} fullerene film 6 formed on the SOI substrate 1, superimposed substrate 1,5 so as to contact the _{C 60} fullerene film 6 formed on the Si substrate 5 The substrates are heated to 350 ° C. in a vacuum atmosphere, and the C ₆₀ fullerene films 6 are bonded to each other, thereby firmly bonding the substrates 1 and 5 to each other.
[0029]
Subsequently, the Si substrate 2 and the SiO ₂ film 3 constituting the SOI substrate 1 are removed by polishing and wet etching on the substrates 1 and 5 bonded together.
As a result, as shown in FIG. 3B, a laminate in which the C ₆₀ fullerene film 6 as the first layer and the Si film 3 of the IV group semiconductor as the second layer are laminated on the Si substrate 5. Structure 7 is assumed.
[0030]
Further, using the newly prepared SOI substrate 1 as shown in FIG. 3A and the laminated structure 7 in FIG. 3B, the same procedure as described above is repeated. That is, C ₆₀ and Al are vapor-deposited simultaneously on the Si film 4 of the SOI substrate 1 and the Si film 4 of the laminated structure 7 to form the C ₆₀ fullerene film 6, and these C ₆₀ fullerene films 6 are in contact with each other. In this way, the layers are superposed and heated to 350 ° C. in a vacuum atmosphere to be bonded. Then, the C ₆₀ fullerene film 6 and the Si film 4 are formed on the Si substrate 5 by removing the Si substrate 2 and the SiO ₂ film 3 constituting the SOI substrate 1 by polishing and wet etching. It is set as the laminated structure laminated | stacked alternately.
[0031]
By repeating such a procedure, a structure in which the C ₆₀ fullerene film 6 and the Si film 4 are alternately and repeatedly stacked is manufactured. Thus, as shown in FIG. 3C, two pairs of semiconductor multilayer film reflecting mirrors 8 in which the pair of C ₆₀ fullerene film 6 and Si film 4 is 6 pairs were produced. At this time, with respect to light having a wavelength λ = 1550 nm, the thickness of each layer of the semiconductor multilayer mirror 8 is set to λ / (4n) where n is the refractive index of each layer. That is, the thickness of the C ₆₀ fullerene film 6 which is the first layer with respect to the light having the wavelength λ = 1550 nm acting on the semiconductor multilayer film reflecting mirror 8 is set such that the refractive index of the C ₆₀ fullerene film 6 is n 0 and m 0 is As a positive integer (here 1), m0 · λ / (4 · n0), the thickness of the Si film 4 as the second layer, the refractive index of the Si film 4 is n1, and m1 is a positive integer (1 here) is m1 · λ / (4 · n1).
[0032]
Next, as shown in the cross-sectional structure of FIG. 3D, a resonator structure 10 is formed by sandwiching a Si film 9 between these two sets of semiconductor multilayer film reflecting mirrors 8. For light having a wavelength λ = 1550 nm, the thickness of the Si film 8 is λ / n, where n is the refractive index of the Si film 9. The Si film 8 is formed by laminating the C ₆₀ fullerene film 6 and the Si film 4 on the outermost side (sixth pair counted from the Si substrate 5 side) when the lower semiconductor multilayer mirror 8 is manufactured. At this time, the Si film 4 of the SOI substrate 1 is formed by keeping the thickness of the Si film 8 as described above. Further, the Si substrate 5 of the upper semiconductor multilayer film reflecting mirror 8 is removed by polishing or the like.
[0033]
Finally, as shown in FIG. 3E, electrodes 11 are attached to the front and back surfaces of the resonator structure 10 to form a wavelength tunable filter 12. A DC power source 13 is connected to the electrode 11. In FIG. 3E, L1 is incident light incident on the wavelength tunable filter 12, and L2 is transmitted light transmitted through the wavelength tunable filter 12.
[0034]
The reflection spectrum of this resonator structure 10 is shown in FIG. By supplying a current to the resonator structure 10 by the DC power source 13, the refractive index of the C ₆₀ fullerene film 6 is changed mainly in a change in the resonant frequency as shown in FIG. That is, it was found that the position of the dip in the reflection spectrum changes according to the current value (0 mA, 5 mA, 10 mA), and the frequency of the transmission band changes.
[0035]
Here, a part of the semiconductor multilayer reflector is a semi-insulating layer or a pn diode structure that allows only a small current to flow, and a structure that changes light absorption or refractive index by changing the semiconductor band structure by applying voltage. Also, an optical modulator having the same effect can be manufactured.
[0036]
Further, instead of the Si film, a GaP film or a III-V group compound semiconductor film in which As, Sb, and In are all 1% or less can be used.
[0037]
[Embodiment 3]
A third embodiment of the present invention will be described with reference to FIG. In the third embodiment, a surface emitting laser structure 21 was produced as shown in FIG.
[0038]
Specifically, a C ₆₀ fullerene film 23 as a first layer and a C ₉₀ fullerene film 24 as a second layer are alternately and repeatedly stacked on an n-type Si substrate 22 using a K cell. Two pairs of semiconductor multilayer film reflecting mirrors 25 having 6 pairs of fullerene films 23 and 24 were produced. Here, in order to make the C ₆₀ fullerene film 23 and the C ₉₀ fullerene film 24 conductive, vapor deposition was performed simultaneously with C ₆₀ or C ₉₀ and Al to form respective fullerene films 23 and 24. By co-evaporating Al, the C ₆₀ fullerene film 23 and the C ₉₀ fullerene film 24 changed in carrier concentration from n 10 -type 10 ¹⁰ cm ⁻³ to 10 ¹⁸ cm ⁻³ and became low resistance.
[0039]
Further, as shown in FIG. 5C, after a GaInAs layer 28 lattice-matched to InP is laminated on the InP substrate 27 by 1 μm, an n-InP layer 29 having a layer thickness of 170 nm and a light emission of 1400 nm are formed on the GaInAs layer 28. A repetitive multilayer film of GaInAsP and 1200 nm light-emitting GaInAsP, a quantum well structure 30 having a total thickness of 50 nm that emits light of 1300 nm, a p-InP layer 31 having a layer thickness of 50 nm, an n-InP layer 32 having a layer thickness of 170 nm, and Were continuously grown.
[0040]
Thereafter, this is bonded to a pair of semiconductor multilayer film reflectors (fullerene reflectors) 25, and then the GaInAs layer 28 and the InP substrate 27 are removed to form a light emitting layer 33 as shown in FIG. did. Then, another set of semiconductor multilayer mirrors (fullerene reflectors) 25 was bonded to the light emitting layer 33 to produce the structure of the tunnel diode type surface emitting laser 21 shown in FIG. 5B.
[0041]
In this case, with respect to light of a wavelength λ that act, the thickness of the C ₆₀ fullerene film 23 is a first layer, the refractive index of the C ₆₀ fullerene film 23 and n0, the m0 is a positive integer (e.g. 1) , M0 · λ / (4 · n0), and the thickness of the C ₉₀ fullerene film 24 as the second layer is such that the refractive index of the C ₉₀ fullerene film 24 is n1 and m1 is a positive integer (eg, 1). , M1 · λ / (4 · n1).
[0042]
The light emitting layer 33 is sandwiched between the C ₆₀ fullerene films 23 of the upper and lower semiconductor multilayer mirrors 25. That is, the C ₉₀ fullerene film 24 on the outermost side (sixth pair counted from the Si substrate 22 side) of the upper and lower semiconductor multilayer film reflecting mirrors 25 is removed by polishing or the like to remove the sixth pair of C ₆₀ fullerene film 23. After the outermost layer is formed, the light emitting layer 33 is sandwiched between the C ₆₀ fullerene films 23. Further, the Si substrate 22 of the upper semiconductor multilayer film reflecting mirror 25 is thinned by polishing or the like to have a predetermined thickness (for example, a wavelength of λ, a refractive index of n and a thickness of λ / (4n)) It has become.
[0043]
Then, Al electrodes 34 are formed on the front and back surfaces of the structure of the surface emitting laser 21, and a current is passed through the surface emitting laser 21 by a DC power source 35 connected to these electrodes 34, as shown in FIG. Laser oscillation was confirmed. L3 in FIG. 5B is a laser beam output from the surface emitting laser 21.
[0044]
Here, the reflecting mirrors on both sides of the light emitting layer 33 constituting the vertical resonator structure are all semiconductor multilayer film reflecting mirrors 25. However, the reflecting mirror is not necessarily limited to this, and the reflecting mirror on one side is not the other reflecting mirror. It may be a mirror (for example, a dielectric multilayer film reflecting mirror).
[0045]
Although fullerenes are C ₆₀ and C ₉₀ here, the same effect can be obtained with metal-encapsulated fullerenes such as metal-encapsulated Er @ C ₈₄ , Er ₂ @C ₈₅ , and Y @ C ₈₂ . The same effect can be obtained by using p-type fullerene doped with nitrogen or phosphorus, or substituted with C of fullerene. Furthermore, it is possible to incorporate such a fullerene semiconductor multilayer mirror as a part of a surface photodiode, a surface modulator, a surface filter, or the like.
[0046]
【The invention's effect】
Thus, by using the semiconductor multilayer film reflecting mirror of the present invention, since it is less toxic, an environment-friendly and high-performance surface optical device is manufactured. This is particularly effective for inexpensive and good surface emitting lasers. In addition, since an abundant resource is used on the earth, an inexpensive optical communication system that greatly reduces manufacturing and disposal costs is provided. It also eliminates the anxiety that can bring so much poison to society.
[Brief description of the drawings]
FIG. 1 is a graph showing the refractive index and absorption wavelength dispersion of Si and C ₆₀ fullerenes.
FIG. 2 is a diagram illustrating a manufacturing procedure of a resonator structure.
FIG. 3 is a diagram showing a manufacturing procedure of a resonator structure.
FIG. 4 is a diagram showing a change in resonance frequency due to current injection in a reflection spectrum.
FIG. 5 is a view showing a surface emitting laser using fullerene.
FIG. 6 is a diagram showing light output with respect to current injection of a surface emitting laser.
[Explanation of symbols]
1 SOI substrate 2 Si substrate 3 SiO ₂ film 4 Si film 5 Si substrate 6 _{C 60} fullerene film 7 laminated structure 8 semiconductor multilayer reflection mirror 9 Si film 10 cavity structure 11 electrode 12 tunable filter 13 DC power supply 21 side emitting laser 22 Si substrate 23 C ₆₀ fullerene film 24 C ₉₀ fullerene film 25 Semiconductor multilayer mirror 27 InP substrate 28 GaInAs layer 29 n-InP layer 30 GaInAsP quantum well structure 31 p-InP layer 32 n-InP layer 33 light emitting layer 34 Al Electrode 35 DC power supply

Claims (14)

A first layer (refractive index n0) made of fullerene (Cn1) and a second layer (refractive index n1) made of fullerene (Cn2) having a refractive index different from that of the first layer are alternately laminated. Composed of
For the acting light (wavelength λ), the thickness of the first layer is m0 · λ / (4 · n0), where m0 is a positive integer, and the thickness of the second layer is m1 as a positive integer. m1 · λ / (4 · n1), a semiconductor multilayer mirror. A first layer (refractive index n0) made of fullerene (Cn1) and a second layer (refractive index n1) made of a group IV semiconductor having a refractive index different from that of the first layer were alternately stacked. Composed of structure,
For the acting light (wavelength λ), the thickness of the first layer is m0 · λ / (4 · n0), where m0 is a positive integer, and the thickness of the second layer is m1 as a positive integer. m1 · λ / (4 · n1), a semiconductor multilayer mirror. The semiconductor multilayer film reflector according to claim 2,
A semiconductor multilayer film reflecting mirror, wherein the group IV semiconductor is Si. A first layer (refractive index n0) made of fullerene (Cn1) and a second layer (refractive index n1) made of a II1-V group semiconductor having a refractive index different from that of the first layer are alternately stacked. Constructed with
For the acting light (wavelength λ), the thickness of the first layer is m0 · λ / (4 · n0), where m0 is a positive integer, and the thickness of the second layer is m1 as a positive integer. m1 · λ / (4 · n1), a semiconductor multilayer mirror. The semiconductor multilayer mirror according to claim 4,
A semiconductor multilayer reflector, wherein the III-V semiconductor is GaP. The semiconductor multilayer mirror according to claim 4,
A semiconductor multilayer film reflecting mirror characterized in that the contents of As, Sb, and In of group III-V semiconductors are all 1% or less. The semiconductor multilayer mirror according to claim 1, wherein
A semiconductor multilayer mirror, wherein the orders n1 and n2 of the first layer made of fullerene (Cn1) and the second layer made of fullerene (Cn2) are both 60 or more and 200 or less. The semiconductor multilayer film reflecting mirror according to any one of claims 2 to 6,
An order n1 of a first layer made of fullerene (Cn1) is 60 or more and 200 or less. The semiconductor multilayer film reflector according to any one of claims 1 to 8,
A semiconductor multilayer film reflecting mirror, wherein impurities are doped so that both the first layer and the second layer are p-type or n-type. The semiconductor multilayer reflector according to any one of claims 1 to 9,
The wavelength that becomes the peak reflectance can be changed by changing the refractive index of the first layer or the second layer by applying a current or applying a voltage. Semiconductor multilayer film reflector. An optical semiconductor device comprising the semiconductor multilayer reflector according to any one of claims 1 to 9,
A vertical resonator structure composed of the upper semiconductor multilayer reflector, an intermediate layer, and the lower semiconductor multilayer reflector;
A semiconductor multilayer film having a function of a wavelength tunable filter by applying a current to the semiconductor multilayer film reflector on the upper side and the semiconductor multilayer film reflector on the lower side or applying a voltage. An optical semiconductor device including a reflector. An optical semiconductor device comprising the semiconductor multilayer reflector according to any one of claims 1 to 9,
A vertical resonator structure having at least one semiconductor multilayer reflector and a light emitting layer;
An optical semiconductor device including a semiconductor multilayer mirror, which has a surface emitting laser function. An optical semiconductor device comprising the semiconductor multilayer reflector according to any one of claims 1 to 9,
And comprising at least one semiconductor multilayer film reflector and a light receiving layer,
An optical semiconductor device including a semiconductor multilayer mirror, characterized by having a photodiode function. An optical semiconductor device comprising the semiconductor multilayer reflector according to any one of claims 1 to 9,
And comprising at least one semiconductor multilayer film reflector and a light modulation layer,
An optical semiconductor device including a semiconductor multilayer film reflecting mirror, which has a function of an optical modulator.

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