JP3449698B2 - Photonic crystal structure and fabrication method - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention constitutes a photonic crystal structure and a manufacturing method, more specifically, various optical devices such as lasers, optical waveguides and optical integrated circuits used for optical information processing, optical transmission and the like. The present invention relates to a basic structure and a manufacturing method thereof.

[0002]

2. Description of the Related Art It is known that light is periodically perturbed in a dielectric periodic structure and that the frequency dispersion has a band structure similar to that of electrons in a crystal. The structure is called a photonic crystal. Since the propagation of light in a photonic crystal is determined by the band structure, its optical properties can be freely designed by controlling the crystal structure and the magnitude of periodic perturbation.

The usefulness of such a photonic crystal was first described by Yablonovitch in 1987.
It has been pointed out that light can be completely confined by using a photonic crystal (photonic bandgap material) having a three-dimensionally open bandgap (E. Yablono).
vitch, Phys. Rev. Lett. 58205
9 (1987)).

Although the three-dimensional photonic crystal has a submicron three-dimensional periodic structure and is not easy to manufacture, several methods have been proposed and attempts have been made so far.

Two typical three-dimensional photonic crystal manufacturing methods will be described. The structure shown in FIG. 15 is a block-like structure formed by stacking rods 1 arranged at regular intervals by rotating them 90 degrees while shifting their phases by a half cycle. This structure is a method (S
-Y. Lin et al. , Nature394, 2
51 (1998)) and a method of repeating wafer attachment (S. Noda et al. IEEE J. Light).
twew Technol. LT17, 1948 (1
999)), an attempt has been made to produce crystals, but since the production process is complicated and the number of processes is large, and accurate alignment is required in each process, crystals of sufficient size have not yet been produced.

As a manufacturing method different from this, first, referring to FIG.
It is said that the three-dimensional periodic structure shown in FIG. 16 (b) is produced by alternately laminating layers 4 and 4'having different dielectric constants on the substrate 3 having the two-dimensional periodic groove 2 shown in FIG. 6 (a). There is a way. This method itself was pointed out by Yablonovitch in the above-mentioned paper of 1987, but when the normal lamination conditions are used, the surface 5 is rapidly planarized, so that the structure actually produced is as shown in FIG. And
A three-dimensional periodic structure cannot be produced by this method.

However, after that, a shape-preserving mode (automatic cloning mode) for preserving the irregularities of the substrate was found by using a specific mode of bias sputtering, and the fabrication of a three-dimensional periodic structure using this was reported (S. Ka
wakami, Electronics Letter
s 33, 1260, 1997). When the alternate multilayer film 8 is stacked in this shape preservation mode on the substrate 7 ((a) of FIG. 18) on which the two-dimensional periodic structure 6 is formed, (b) of FIG.
As shown in FIG. 5, the alternating multilayer film 8 having the shape in which the two-dimensional periodic structure 6 of the substrate 7 is preserved is formed. The process of forming the three-dimensional periodic structure by this method will be specifically described.

First, a three-dimensional periodic structure is formed by forming a two-dimensional periodic hole structure by lithography and dry etching and stacking an alternating laminated structure of Si / SiO ₂ on this two-dimensional periodic structure by an auto cloning mode. It is made. It has already been confirmed that the flattening of the surface does not occur even in the lamination of 40 layers or more and the shape preservation is maintained.

This method has a feature that the manufacturing process is far simpler than that of the above-mentioned method, and a three-dimensional photonic crystal having a large film thickness can be manufactured relatively easily. However, the structure manufactured by this method has a problem that it is difficult to open the band gap in all directions, although a large gap opens in the stacking direction.

On the other hand, the two-dimensional photonic crystal is shown in FIG.
As shown in (a), (b), and (c), it can be produced by transferring by dry etching with good verticality using a mask pattern 9 by lithography, and is produced in comparison with a three-dimensional photonic crystal. It's easy. That is, a mask pattern 9 is formed by lithography (see FIG.
(A)), the vertical hole 10 is formed by vertical etching (FIG. 19 (b)), and the mask pattern 9 is removed to obtain the two-dimensional photonic crystal of FIG. 19 (c). 19 (a) and 19 (b) are side views of the crystal.
The upper view of (c) is a side view, and the lower view is a plan view.

Attempts have been made to fabricate two-dimensional and three-dimensional photonic crystals by the above-mentioned method. However, when the photonic crystal is applied to a device, the above defect-free crystal structure alone is sufficient. It cannot have a function. In order to have a function and operate the device, it is necessary to artificially introduce structural defects into the photonic crystal.

When a line defect is formed in a photonic crystal with an open band gap, a waveguide 11 capable of propagating light is formed in that part (FIG. 20 (a)), and when a point defect is formed, it is formed in that part. The light is confined to form the resonator 12 ((b) of FIG. 20).

In the waveguide 11 and the resonator 12 formed in this way, the defective portion is surrounded by a photonic crystal which is not allowed to enter light, so that light confinement is realized, and a normal light guide is performed. Waveguide 11 and optical resonator 12
Remarkably stronger confinement can be realized compared to.

In the case where the single defect waveguide 11 in the two-dimensional square lattice photonic crystal as shown in FIG.
Numerical calculations have shown that the scattering loss and the reflection loss can be almost zero (Mekis et a.
l. Phys. Rev. Lett. 77, 3787 (1
996)). When an optical circuit is configured by a waveguide or a resonator due to such a defect in the photonic crystal, each size can be on the order of wavelength, and therefore the size of the circuit can be significantly reduced.

When aiming at miniaturization of such an optical circuit, it is technically difficult to realize a circuit configuration including a complicated defect because it is difficult to produce a defect-free periodic structure of a three-dimensional photonic crystal. Very difficult.

On the other hand, an integrated circuit, which is usually an electronic device or an optical device, is often closed in a two-dimensional plane. Therefore, the circuit configuration itself can be realized by a two-dimensional photonic crystal. The two-dimensional photonic crystal is considerably easier to manufacture than the three-dimensional photonic crystal, and it is not so difficult to introduce defects. For the above reasons
At present, waveguides and resonators are mostly researched using two-dimensional photonic crystals.

In the numerical calculation of Mekis et al., The calculation is performed in an ideal two-dimensional system, which corresponds to the case of the infinitely long two-dimensional photonic crystal 14 (FIG. 21). However, in reality, since the two-dimensional photonic crystal is manufactured by a processing technique such as dry etching, the maximum length in the direction perpendicular to the two-dimensional surface is at most several times the wavelength, and the photonic crystal is infinitely long. Cannot be regarded as

In order to effectively form a circuit with such a finite thickness photonic crystal, it is very important how to deal with the upper and lower confinement structures. In many cases, the two-dimensional photonic crystal that has been actually manufactured has a slab structure in which the upper and lower sides of the two-dimensional photonic crystal 14 are sandwiched by air and a low refractive index material 15 such as SiO ₂ (see FIG. Two
2). In addition, 16 is a semiconductor substrate.

In a simple straight waveguide, a lossless waveguide mode may exist in this slab type two-dimensional photonic crystal, but in the case of a bent waveguide, the radiation loss is the most serious.
Although it is possible to prevent the loss in the dimensional plane, radiation loss occurs in an oblique direction deviating from the two-dimensional plane. This problem is the same in the case of a resonator composed of point defects, and the performance as a resonator is deteriorated due to leakage to the obliquely upper surface.

[0020]

SUMMARY OF THE INVENTION According to the present invention, when an optical circuit is composed of a photonic crystal, it is difficult to build a circuit with only a three-dimensional photonic crystal, and a two-dimensional photonic crystal is confined. Solves the problem that is insufficient.

[0021]

In order to solve the above problems, the photonic crystal structure according to the present invention comprises a first three-dimensional photonic crystal, a two-dimensional photonic crystal and a second three-dimensional photonic crystal. It is characterized by having a laminated structure.

Further, the method for producing a photonic crystal structure according to the present invention is a three-dimensional photonic crystal formed by alternately laminating two or more kinds of materials having different refractive indexes on a substrate having a two-dimensional periodic structure. Forming a structure,
By processing the two-dimensional periodic structure by lithography, 2
A step of forming a three-dimensional photonic crystal structure, and subsequently forming a three-dimensional photonic crystal structure formed by alternately laminating two or more kinds of materials having different refractive indexes on the two-dimensional periodic structure. To do.

Further, in the second method for producing a photonic crystal structure according to the present invention, a two-dimensional periodic structure is formed on the first substrate by processing a two-dimensional periodic structure on the first substrate by lithography. Forming a three-dimensional photonic crystal structure, forming a three-dimensional photonic crystal structure by alternately laminating two or more kinds of materials having different refractive indexes on the two-dimensional periodic structure on the surface, the three-dimensional photonic crystal The step of providing a second substrate on the structure, the step of removing the first substrate, and the two-dimensional periodic structure on the back surface of the two-dimensional photonic crystal structure are alternately laminated with two or more kinds of materials having different refractive indexes. Thereby forming a three-dimensional photonic crystal structure.

In the present invention, a structure in which the two-dimensional photonic crystal 14 as shown in FIG. 1 is sandwiched by the three-dimensional photonic crystals 17 is produced. In this figure, the two-dimensional photonic crystal 14 serves as a core, and the three-dimensional photonic crystal 17 serves as a clad for confining light. In this structure, light is basically confined in the two-dimensional photonic crystal part, and the optical circuit is formed in the two-dimensional photonic crystal part. Therefore, all complicated structures such as defects are created in the two-dimensional photonic crystal portion, and the three-dimensional photonic crystal portion has a simple defect-free periodic structure. The fabrication process is relatively simple because it is not necessary to create defects in the three-dimensional photonic crystal.

Since the circuit is formed in a two-dimensional plane, the largest gap must be opened in this two-dimensional plane. In this structure, a large gap due to the two-dimensional photonic crystal is formed in this direction. Is open. It is desirable that the three-dimensional photonic crystal has a full band gap, but it is not always necessary. Especially 2
Since the radiation is suppressed by the two-dimensional photonic crystal in the in-plane direction, it is not necessary to open the gap as the three-dimensional photonic crystal.

Regarding the radiation loss in the oblique direction with respect to the two-dimensional surface, which is a problem in the bending waveguide, etc., the three-dimensional photonic crystal has a large gap in the direction deviating from the two-dimensional surface. Therefore, this radiation loss can be suppressed.

In the present invention, the three-dimensional photonic crystal part is produced by the self-cloning mode of bias sputtering, and the two-dimensional photonic crystal part is produced by lithography and etching.

As a manufacturing process, as shown in the embodiment, a three-dimensional photonic crystal, a two-dimensional photonic crystal and a three-dimensional photonic crystal are manufactured in this order, and a two-dimensional photonic crystal, a three-dimensional photonic crystal and a three-dimensional photonic crystal. Although it may be considered that photonic crystals are produced in this order, in any case, the process of producing a three-dimensional photonic crystal on a two-dimensional photonic crystal is technically the most difficult.

However, in the method for producing a three-dimensional photonic crystal by the self-cloning mode of bias sputtering used here, the three-dimensional photonic crystal is produced by using the period of the underlying two-dimensional photonic crystal as a template, and thus the process is very difficult. To be simplified. Moreover, it is possible to stack the three-dimensional photonic crystal portion without filling the holes of the two-dimensional photonic crystal in the process, and even if a defect such as a waveguide is made in the two-dimensional photonic crystal portion, The three-dimensional photonic crystal produced in step 1 is characterized by being a uniform defect-free photonic crystal.

[0030]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the photonic crystal structure fabrication of the present invention will be described below with reference to the drawings.

[0031]

[Embodiment 1] FIGS. 2 to 6 show a photonic crystal manufacturing process of the present invention in a first embodiment. First, FIGS. 2 to 4 show the same three-dimensional photonic crystal manufacturing process by the self-cloning mode of bias sputtering as has been conventionally reported.

First, a resist pattern is formed on the Si substrate 18 by electron beam exposure, and dry etching is performed using this as a mask to form the two-dimensional periodic structure 6 on the Si substrate (FIG. 2).

Subsequently, an alternate multilayer film 8 of a Si layer 81 and a SiO ₂ layer 82 is laminated on this groove structure by bias sputtering. Here, by using the self-cloning mode, the first two-dimensional periodic structure is preserved in the stacking process, and as a result, the three-dimensional periodic structure shown in the figure is formed (FIG. 3).

The Si layer 81 is also stacked on the three-dimensional periodic structure in the self-cloning mode (FIG. 4). This Si layer 8
A two-dimensional periodic mask pattern is formed on 1 again by electron beam exposure. Dry etching is performed on the mask to form periodic holes 19 in the Si layer 81, and this portion is used as the air hole type two-dimensional photonic crystal 14 (FIG. 5).

Then, Si / Si was again formed on the two-dimensional photonic crystal by self-cloning of bias sputtering.
The SiO ₂ alternating multilayer film 8 is laminated (FIG. 6). This stacking is basically the same process as the stacking of the three-dimensional photonic crystal on the two-dimensional periodic groove in the process b, and the three-dimensional photonic crystal is formed on the two-dimensional photonic crystal as in FIG. It

The above is the outline of the manufacturing process. The most important point in such a manufacturing process is a step of stacking a three-dimensional photonic crystal on a two-dimensional photonic crystal.

First, in this step, the air holes (periodic holes 19) of the two-dimensional photonic crystal are changed to Si or SiO _2.
As a result, the in-plane refractive index modulation of the two-dimensional photonic crystal portion becomes weak, the in-plane gap becomes narrow, and the gap disappears in some cases.

However, in the manufacturing method by bias sputtering used here, the three-dimensional photonic crystal can be formed promptly without depositing Si and SiO ₂ in the periodic holes 19 by selecting the conditions of the self-cloning mode. It is possible.

Specifically, by using the self-cloning condition in which the directivity of the sputtered particles incident on the film is weak, the particles are not incident on the deep part of the hole, and the film is deposited on the edge of the hole, thereby promptly The hole can be closed and the self-cloning mode can be continued.

Further, line defects and point defects are formed in the two-dimensional photonic crystal portion in order to realize a circuit, but if a three-dimensional photonic crystal cannot be formed above this defect, the confinement is weakened accordingly. . In simple terms, in the ideal self-cloning mode, the stacking is performed by tracing the base, so that the defective 3D photonic crystal is stacked on the defective 2D photonic crystal. However, in reality, it is possible to form a defect-free three-dimensional photonic crystal on a defective two-dimensional photonic crystal by the mechanism described below.

In FIG. 4, the uppermost surface of the Si layer 81 laminated in the self-cloning mode on the three-dimensional photonic crystal is
It has the same two-dimensional periodic structure as the upper surface of the three-dimensional photonic crystal part (FIG. 3), and if the alternating multilayer film 8 is stacked on this in the self-cloning mode, the same three-dimensional photonic crystal as in FIG. To be done.

On the other hand, when a defective waveguide is manufactured,
In this step, the shape is formed when the second lithography is performed, and the shape of the structure formed after etching is as shown in FIG. 7A instead of FIG.

In this example, a defect waveguide having a bend of 60 degrees is formed. As can be seen from this figure, since the defective waveguide portion is not etched, the same unevenness as in FIG. 4 remains, and a three-dimensional photonic crystal can be formed on this as well.

Here, by appropriately selecting the bias sputtering conditions in the initial stage of the second self-cloning stacking process, a stable shape appears promptly regardless of the depth of the hole, so that the two-dimensional photonic crystal portion is eventually obtained. The same three-dimensional photonic crystal is formed on the upper portion of both the portion with and without the defect (FIG. 7).
(B)).

In this example, the waveguide portion is not etched at all, but the waveguide can be formed, for example, by making the etching hole diameter of the defective portion smaller than that of the other portions. . Also in this case, it is obvious that a defect-free three-dimensional photonic crystal can be produced on the two-dimensional photonic crystal with defects by the same mechanism as described here.

[0046]

Second Embodiment In order to form a defect-free three-dimensional photonic crystal on a defect by the mechanism described in the first embodiment, the in-plane periodic structure of the lower three-dimensional photonic crystal and the two-dimensional periodic structure are formed on it. The pattern of the two-dimensional photonic crystal must not be misaligned.

In order to prevent this deviation in the method of the first embodiment, it is necessary to secure sufficient alignment accuracy in the lithography process of FIG. 2 and the lithography process of FIG. If the alignment is performed only once as in this case, this alignment is not impossible with the current technology, but it is possible to eliminate the alignment as described below by changing the manufacturing process. .

8 to 13 show the manufacturing process in the second embodiment. In this method, InGa is formed on the GaAs substrate 20.
P layer 21 and GaAs layer (or GaAs / AlGaA
s semiconductor quantum well structure or InGaAs / GaAs semiconductor quantum well structure) 22 is formed on the structure epitaxially grown to form a mask pattern by lithography.
2 on the top GaAs layer 22 by dry etching
A three-dimensional photonic crystal 14 is produced (FIG. 8).

Then, Si / Si is formed by the same method as in the first embodiment.
Three-dimensional photonic crystal 1 by stacking O ₂ alternating multilayer films 8
7 is produced (FIG. 9). Another Si substrate 18 is attached on the surface of the three-dimensional photonic crystal 17 of this substrate by using a wafer bonding technique (FIG. 10). At this time, the unevenness of the upper surface of the three-dimensional photonic crystal may cause a problem when sticking the substrate, but by sticking a soft material such as a polymer on the substrate 18, the sticking can be performed without any problem. .

Subsequently, the GaAs substrate 20 on the back surface is replaced with InGa.
The two-dimensional photonic crystal 14 is removed from the three-dimensional photonic crystal 17 by removing the InGaP layer 21 with another etching solution having a selectivity for P (FIG. 11). The resulting structure is formed (FIG. 12). This structure is structurally almost the same as the structure of FIG. 5 in Example 1 (actually, the symmetry of the lower three-dimensional photonic crystal is reversed). Then, the same structure as that of FIG. 6 is produced by laminating the three-dimensional photonic crystal 17 thereon by self-cloning lamination as in Example 1 (FIG. 13).

In this method, the lithography is performed only once, and therefore, alignment is unnecessary. Also,
In the first embodiment, there is a limitation on the material that the layer (the Si layer in the case of the first embodiment) that will be the two-dimensional photonic crystal portion must be formed by bias sputtering.
Although it was impossible to use a compound semiconductor such as s, in the method of Example 2, the two-dimensional photonic crystal portion was formed prior to the bias sputtering process, so that the material was freely formed regardless of the bias sputtering. You can choose.

Therefore, for example, InGaAs / InGaAs /
It is also possible to use a two-dimensional photonic crystal having a GaAs strained quantum well structure or a GaAs / AlGaAs superlattice structure, and the two-dimensional photonic crystal part can have various active functions. There is.

However, according to this method, since the two-dimensional photonic crystal is first formed, the defective portion has neither the origin of the self-cloning nor the unevenness. For that purpose,
When a defect is created as in (a), a three-dimensional photonic crystal is not formed on it.

However, if a defect due to a difference in hole diameter is used as the defect, a defect-free three-dimensional photonic crystal is formed thereon for the same reason as described in the first embodiment. Actually, if a very small hole is drawn in the defect portion at the stage of lithography, the portion having a small hole diameter can be etched only shallowly due to the loading effect at the time of etching, so that the shape is almost the same as that of the first embodiment. Is created.

[0055]

[Third Embodiment] In the first and second embodiments, all the waveguides are provided in the two-dimensional photonic crystal. However, in the configuration of the present invention, the waveguide is formed in the direction perpendicular to the plane of the two-dimensional photonic crystal. It is also possible to couple the waveguide in the two-dimensional plane with the waveguide perpendicular to the waveguide. 2 like this
The waveguide perpendicular to the plane of dimension is particularly useful as an input / output unit for light.

This structure is shown in FIG. First, the point defects 23 are provided when the two-dimensional periodic groove is formed on the substrate (FIG. 14A). When a multilayer film is stacked on this by self-cloning, a one-dimensional periodic structure is formed in this point defect portion instead of a three-dimensional periodic structure, and this portion becomes a vertical waveguide (FIG. 14A). ).

Thereafter, as in the case of the first embodiment, a two-dimensional photonic crystal 14 having a defect waveguide is formed thereon, and the defect waveguide in this two-dimensional plane and the first point defect overlap. (FIG. 14B). If a three-dimensional photonic crystal 17 is further formed on this (FIG.
A waveguide structure having a vertical extraction waveguide as shown in (c) is produced.

In the first, second, and third embodiments described above, Si and Si are used as the material of the portion produced by bias sputtering.
Although O ₂ was used, it is clear that basically the same effect can be expected in this portion as long as it is a material capable of forming a film by bias sputtering.

Although the GaAs layer having the InGaP layer as the etching stop layer and the quantum well structure are used as the two-dimensional photonic crystal portion in the second embodiment, any combination of the etching stop layer and the material that can be etched can be used. The same effect can be expected with any material.

For example, InGaAsP / I is formed on an InP substrate.
It is obvious that the same effect can be expected with a combination of an InP-based quantum well structure such as nGaAs and an InP or InGaAs etching stop layer. Further, the two-dimensional photonic crystal portion has an air hole square lattice structure, but the same effect can be obtained with a pillar structure or a triangular lattice structure.

[0061]

As described above, in the photonic crystal structure according to the present invention, the three-dimensional photonic crystal is formed on the front and back surfaces of the two-dimensional photonic crystal. It is possible to solve the problem that it is difficult to build a circuit only with the two-dimensional photonic crystal, and the confinement is insufficient with the two-dimensional photonic crystal. Further, according to the method for producing a photonic crystal structure of the present invention, a three-dimensional photonic crystal having an alternating multilayer film can be obtained by self-cloning on a two-dimensional periodic structure. Therefore, the photonic crystal structure can be easily produced. can do.

[Brief description of drawings]

FIG. 1 is a schematic diagram showing a photonic crystal structure proposed by the present invention.

FIG. 2 is a schematic view showing a photonic crystal structure manufacturing process in Embodiment 1 of the present invention, which is a perspective view and a sectional view of a substrate having a two-dimensional periodic structure.

3A and 3B are schematic views showing a photonic crystal structure manufacturing process according to the first embodiment of the present invention, which are a perspective view and a cross-sectional view when an alternate multilayer film is laminated on the substrate.

FIG. 4 is a schematic view showing a photonic crystal structure manufacturing process in Example 1 of the present invention, which is a perspective view and a cross-sectional view of manufacturing a two-dimensional photonic crystal.

5A and 5B are schematic views showing a photonic crystal structure manufacturing process according to the first embodiment of the present invention, which are a perspective view and a sectional view when two-dimensional photonic crystals are stacked.

FIG. 6 is a schematic view showing a photonic crystal structure manufacturing process in Example 1 of the present invention, and is a perspective view and a sectional view when a three-dimensional photonic structure is laminated on the secondary photonic crystal structure.

FIG. 7 is a schematic diagram showing a photonic crystal structure manufacturing process with line defects in the present invention.

8A and 8B are schematic views showing a photonic crystal structure manufacturing process in Example 2 of the present invention, and are perspective views and cross-sectional views when a two-dimensional photonic crystal is manufactured on a substrate.

FIG. 9 is a schematic view showing a photonic crystal structure manufacturing process in Example 2 of the present invention, and is a perspective view and a sectional view when a three-dimensional photonic crystal is manufactured on a two-dimensional photonic crystal.

FIG. 10 is a schematic view showing a photonic crystal structure manufacturing process in Example 2 of the present invention, and is a perspective view and a sectional view when a second substrate is manufactured on a three-dimensional photonic crystal.

FIG. 11 is a schematic view showing a photonic crystal structure manufacturing process in Embodiment 2 of the present invention, which is a perspective view and a sectional view when the first substrate is removed.

12A and 12B are schematic views showing a photonic crystal structure manufacturing process according to a second embodiment of the present invention, showing a perspective view and a sectional view when the first substrate is removed.

FIG. 13 is a schematic view showing a photonic crystal structure manufacturing process in Example 2 of the present invention, which is a perspective view and a sectional view when a three-dimensional photonic crystal is formed on the back surface of the two-dimensional photonic crystal.

FIG. 14 is a schematic diagram showing a photonic crystal structure manufacturing process having a vertical optical waveguide and an in-plane optical waveguide by introducing line defects and point defects in the third embodiment of the present invention.

FIG. 15 is a schematic diagram showing a method for manufacturing a rod-stacked three-dimensional photonic crystal.

FIG. 16a is a schematic view showing a substrate on which two-dimensional periodic grooves are formed by lithography and etching.

16b is a schematic diagram showing a three-dimensional photonic crystal structure produced by performing ideal alternate stacking on the structure of FIG. 16a.

FIG. 17 is a schematic view showing a structure actually manufactured when stacking is performed under normal stacking conditions.

Fig. 18 Shape storage mode (automatic cloning mode)
FIG. 3 is a schematic view showing a process of alternately stacking a substrate having a periodic structure using the above method and a three-dimensional periodic structure actually formed.

FIG. 19 is a schematic diagram showing a method for producing a two-dimensional photonic crystal on a semiconductor substrate by lithography and dry etching.

FIG. 20 is an optical waveguide structure (a) due to a line defect provided in a two-dimensional photonic crystal, an optical resonator (b) due to a point defect, and a right-angled bend waveguide (c) due to a curved line defect.
FIG.

FIG. 21 is a schematic diagram showing an ideally long two-dimensional photonic crystal.

FIG. 22 is a schematic diagram showing the structure of a slab type two-dimensional photonic crystal.

[Explanation of symbols]

1 rod 2 two-dimensional periodic groove 3 substrates 4 Layers with different permittivity 4'Layer with different permittivity 5 surface 6 Two-dimensional periodic structure 7 substrate 8 Alternate multilayer film 9 Mask pattern 10 vertical holes 11 Waveguide 12 point defect 13 Bend 14 Two-dimensional photonic crystal 15 Low refractive index material 16 Semiconductor substrate 17 Three-dimensional photonic crystal 18 Si substrate 19 periodic holes 20 GaAs substrate 21 InGaP layer 22 GaAs layer 23 point defects

─────────────────────────────────────────────────── ─── Continuation of front page (51) Int.Cl. ⁷ Identification code FI G02B 6/12 M (72) Inventor Toshiaki Tamamura 2-3-1, Otemachi, Chiyoda-ku, Tokyo Nippon Telegraph and Telephone Corporation (72 ) Inventor Chiharu Takahashi 2-3-1 Otemachi, Chiyoda-ku, Tokyo Inside Nippon Telegraph and Telephone Corporation (72) Inventor Akihiko Shinya 2-3-1 Otemachi, Chiyoda-ku, Tokyo Inside Nippon Telegraph and Telephone Corporation (72 ) Inventor Shojiro Kawakami, 236, Tohigai, Wakabayashi-ku, Sendai-shi, Miyagi (72) Inventor, Takayuki Kawashima 45-5 Kawauchi, Sanju-cho, Aoba-ku, Sendai-shi, Miyagi 203 (56) References 11-218627 (JP, A) JP 10-335758 (JP, A) (58) Fields investigated (Int.Cl. ⁷ , DB name) G02B 6/12 C23C 14/06 G02B 6/13 H01S 5 / 20 H01S 5/343

Claims (9)

(57) [Claims] 1. A photonic crystal structure having a structure in which a first three-dimensional photonic crystal, a two-dimensional photonic crystal and a second three-dimensional photonic crystal are laminated. 2. The photonic crystal structure according to claim 1, wherein the two-dimensional photonic crystal has periodic periodic holes. 3. The photonic crystal structure according to claim 2, wherein the two-dimensional photonic crystal has a waveguide due to defects of periodic periodic holes. 4. The photonic crystal structure according to claim 1, wherein the two-dimensional photonic crystal has a semiconductor well structure or a semiconductor hetero structure. 5. The photonic crystal structure according to claim 1, wherein the three-dimensional photonic crystal has an input / output waveguide in the stacking direction. 6. A substrate on which a two-dimensional periodic structure is formed, 2
A step of forming a three-dimensional photonic crystal structure formed by alternately laminating materials of different types or more having different refractive indexes, a step of forming a two-dimensional photonic crystal structure by processing a two-dimensional periodic structure by lithography, Then, a method for producing a photonic crystal structure, which comprises forming a three-dimensional photonic crystal structure by alternately laminating two or more kinds of materials having different refractive indexes on the two-dimensional periodic structure. 7. A lithographically formed 2 layer on the first substrate.
Process of three-dimensional periodic structure to form a two-dimensional photonic crystal structure in which two-dimensional periodic structures are formed on the front and back surfaces, and two or more kinds of materials having different refractive indices are formed on the two-dimensional periodic structure A step of forming a three-dimensional photonic crystal structure by alternately stacking, a step of providing a second substrate on the three-dimensional photonic crystal structure, a step of removing the first substrate, the two-dimensional photonic crystal structure And a step of forming a three-dimensional photonic crystal structure by alternately laminating two or more kinds of materials having different refractive indices on the two-dimensional periodic structure on the back surface of the above. 8. The method for producing a photonic crystal structure according to claim 7, wherein the three-dimensional photonic crystal is produced by a shape preservation mode (self-cloning mode) in bias sputtering. 9. The method for producing a photonic crystal structure according to claim 6, wherein point defects are provided in the two-dimensional periodic structure of the substrate.