JPH0572561B2 - - Google Patents
Info
- Publication number
- JPH0572561B2 JPH0572561B2 JP59170144A JP17014484A JPH0572561B2 JP H0572561 B2 JPH0572561 B2 JP H0572561B2 JP 59170144 A JP59170144 A JP 59170144A JP 17014484 A JP17014484 A JP 17014484A JP H0572561 B2 JPH0572561 B2 JP H0572561B2
- Authority
- JP
- Japan
- Prior art keywords
- optical
- optical waveguide
- germanium
- light
- waveguide region
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired - Lifetime
Links
- 230000003287 optical effect Effects 0.000 claims description 44
- 239000004065 semiconductor Substances 0.000 claims description 15
- 229910052732 germanium Inorganic materials 0.000 claims description 10
- 229910052710 silicon Inorganic materials 0.000 claims description 10
- 239000000758 substrate Substances 0.000 claims description 9
- XUIMIQQOPSSXEZ-UHFFFAOYSA-N Silicon Chemical compound [Si] XUIMIQQOPSSXEZ-UHFFFAOYSA-N 0.000 claims description 7
- 239000013078 crystal Substances 0.000 claims description 7
- GNPVGFCGXDBREM-UHFFFAOYSA-N germanium atom Chemical compound [Ge] GNPVGFCGXDBREM-UHFFFAOYSA-N 0.000 claims description 7
- 239000010703 silicon Substances 0.000 claims description 7
- 230000000694 effects Effects 0.000 description 4
- 229910013641 LiNbO 3 Inorganic materials 0.000 description 3
- 230000005540 biological transmission Effects 0.000 description 3
- 238000005516 engineering process Methods 0.000 description 3
- 239000000463 material Substances 0.000 description 3
- 229910000980 Aluminium gallium arsenide Inorganic materials 0.000 description 2
- 230000000903 blocking effect Effects 0.000 description 2
- 230000008878 coupling Effects 0.000 description 2
- 238000010168 coupling process Methods 0.000 description 2
- 238000005859 coupling reaction Methods 0.000 description 2
- 238000009792 diffusion process Methods 0.000 description 2
- 239000010408 film Substances 0.000 description 2
- 239000013307 optical fiber Substances 0.000 description 2
- 239000010409 thin film Substances 0.000 description 2
- 238000005773 Enders reaction Methods 0.000 description 1
- 229910003327 LiNbO3 Inorganic materials 0.000 description 1
- 238000004891 communication Methods 0.000 description 1
- 238000010586 diagram Methods 0.000 description 1
- 230000010365 information processing Effects 0.000 description 1
- 239000012212 insulator Substances 0.000 description 1
- 238000005468 ion implantation Methods 0.000 description 1
- 230000001678 irradiating effect Effects 0.000 description 1
- 238000004519 manufacturing process Methods 0.000 description 1
- 238000000034 method Methods 0.000 description 1
- 230000010355 oscillation Effects 0.000 description 1
- 238000001947 vapour-phase growth Methods 0.000 description 1
Classifications
-
- G—PHYSICS
- G02—OPTICS
- G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
- G02B6/00—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings
- G02B6/10—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings of the optical waveguide type
- G02B6/12—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings of the optical waveguide type of the integrated circuit kind
- G02B6/122—Basic optical elements, e.g. light-guiding paths
- G02B6/125—Bends, branchings or intersections
Landscapes
- Physics & Mathematics (AREA)
- Engineering & Computer Science (AREA)
- Microelectronics & Electronic Packaging (AREA)
- General Physics & Mathematics (AREA)
- Optics & Photonics (AREA)
- Optical Integrated Circuits (AREA)
Description
（発明の技術分野）
本発明は半導体から成る光スイツチや光変調器
等の光半導体素子に関するものである。
（従来技術とその問題点）
光スイツチや光変調器などの光半導体素子は光
フアイバ伝送の分野だけでなく、光交換あるいは
光情報処理の分野においても注目されつつあり、
一部開発が進められている。従来のこのような素
子は、LiNbO3、LiTaO3などの絶縁体、又は
AlGaAs系、InGaAsP系から成る半導体で構成さ
れていた。その理由は、例えば、LiNbO3などで
は電気光学効果が大きく、また、AlGaAs、
InGaAsP系などでは発光源や光検出器といつた
光素子としての開発がかなり進んでいることなど
である。しかしながら、これらの結晶材料は、価
格が高く例えば、光交換機のように大量の光スイ
ツチを必要とするものには適用が困難である。ま
た、光導波領域を再現性良く形成するのが難し
く、LiNbO3等では信頼性の点で問題があつた。
〔また、信頼性の面では大きな利点を有する半
導体材料については、特願昭49−22952号におい
てシリコン（Si）にゲルマニウム（Ge）を添加
した光波伝送路が開示されている。然るに、Siに
Geを拡散したり、Siの気相成長の際Geを添加す
るのでは、Siに対する屈折率は一般に少数点以下
２桁目が僅かに大きくなる程度であり、（例えば、
電子通信学会論文誌、vol.1， Ｊ−60−Ｃ No.
10，pp610−617にLiNbO3へのTi拡散の例が表示
されている。）、光波伝送路として機能するために
は、例えば光フアイバのコアのように導波路部分
の大きさが10μm乃至数10μmと大きくなり、半導
体の特徴である1μmあるいはそれ以下の薄膜を利
用した小型導波路を形成したことができない。従
つてSiにGeを添加した従来の光導波路は、半導
体技術の観点から見れば大きすぎてしかも極めて
高価となり、実用化ができないという欠点があつ
た。
（発明の目的と特徴）
本発明は、上述のような従来の光素子材料の有
する欠点を解決するためになされたもので、高い
製造精度で大量生産でき、かつ集積電子回路との
整合性も良い光スイツチや光変調器などの光半導
体素子を提供することを目的としており、シリコ
ン基板上の光導波領域をゲルマニウムの組成が16
％以上のシリコンとゲルマニウムの混晶を用いて
構成するところに特徴がある。
（発明の構成と作用）
以下に図面を用いて本発明を詳細に説明する。
(Technical Field of the Invention) The present invention relates to optical semiconductor devices such as optical switches and optical modulators made of semiconductors. (Prior art and its problems) Optical semiconductor devices such as optical switches and optical modulators are attracting attention not only in the field of optical fiber transmission but also in the field of optical switching and optical information processing.
Some development is underway. Conventional such elements are made of insulators such as LiNbO 3 , LiTaO 3 , or
It was composed of AlGaAs-based and InGaAsP-based semiconductors. The reason is that, for example, LiNbO 3 has a large electro-optic effect, and AlGaAs,
The development of InGaAsP systems as optical devices such as light emitting sources and photodetectors has progressed considerably. However, these crystal materials are expensive and difficult to apply to devices that require a large number of optical switches, such as optical exchangers. In addition, it is difficult to form the optical waveguide region with good reproducibility, and LiNbO 3 and the like have problems in terms of reliability. [Also, regarding semiconductor materials that have great advantages in terms of reliability, Japanese Patent Application No. 49-22952 discloses a light wave transmission line in which germanium (Ge) is added to silicon (Si). However, Si
When Ge is diffused or added during vapor phase growth of Si, the refractive index for Si is generally only slightly larger in the second digit after the decimal point (for example,
Journal of the Institute of Electronics and Communication Engineers, vol.1, J-60-C No.
10, pp610-617 shows an example of Ti diffusion into LiNbO3 . ), in order to function as a light wave transmission path, the size of the waveguide part, such as the core of an optical fiber, must be large, from 10 μm to several tens of μm, and it is necessary to use a thin film of 1 μm or smaller, which is a characteristic of semiconductors, to create a small waveguide. It is not possible to form a waveguide. Therefore, conventional optical waveguides made of Si doped with Ge have the drawback of being too large and extremely expensive from the perspective of semiconductor technology, making them impractical for practical use. (Objective and Features of the Invention) The present invention has been made to solve the above-mentioned drawbacks of conventional optical element materials, and it can be mass-produced with high manufacturing precision and has good compatibility with integrated electronic circuits. The aim is to provide optical semiconductor devices such as good optical switches and optical modulators, and the optical waveguide region on the silicon substrate is made of germanium with a composition of 16.
% or more of silicon and germanium. (Structure and operation of the invention) The present invention will be explained in detail below using the drawings.
【表】
表１はシリコン（Si）とゲルマニウム（Ge）
の格子定数ａ、屈折率ｎ、および禁制帯幅Egを
示したものである。SiとGeの混晶Si1-xGexの格
子定数、屈折率、および禁制帯幅は線形近似を用
いて、すなわち、SiからGeまでｘに対して直線
的に変化すると仮定して、推定できる。例えば、
ｘ＝0.1とすると、Si0.9Ge0.1の屈折率は3.56と見
積もることができる。逆に、Si1-xGexを光導波領
域として用いる場合、周囲のSiとの屈折率差Δn
が約0.1程度必要とすれば、ｘ0.16となり、そ
の時の格子不整合Δa／ａ（Si）は約0.6％、禁制
帯幅の差ΔEgは約0.07eVとなる。これらの諸定
数データをもとに、次に具体的な光半導体素子の
〔構造例〕について説明する。
第１図は本発明の〔原理的構成〕を示したもの
で、光スイツチや光変調器として作動する光方向
性結合器の模式図である。ｎ型Si基板１の表面
に、光導波領域となる場所に溝４が形成されてお
り、その上にｎ型のSiとGeの混晶Si1-xGex２、
およびn-型のSi３が積層されている。５および６
は電極であり、７は変調用信号電源を示してい
る。
第２図は第１図のＡ−Ｂ面に沿う断面を示した
もので、８はイオン打込み又は拡散によりｐ型と
なつた領域である。SiとGeの混晶比ｘを前述の
ように、例えば約0.16とすれば、Si0.84Ge0.16光導
波路２とSiとの屈折率差が約0.1となり、第２図
のような溝４を設けることにより、点線で示した
光導波領域９が容易に形成される。溝に沿つて導
びかれる光は、二つの溝４の間隔を適当に設定す
ることにより一方の溝から他方の溝へ移つてい
く。すなわち方向性結合器が生じる。ここで、例
えば変調信号源７から電極５およびｐ型Si領域８
を通して変調電流を溝と溝との間のSi1-xGex層２
に注入すると、その部分の屈折率がプラズマ振動
効果により変化する。従つて、二つの光導波領域
間の結合定数が変化するため、導波される光は変
調を受けることになる。
第３図は本発明の実施例を示したものである。
Si基板１０の表面に溝４が設けられており、その
上にSi1-xGexとSi1-yGeyとの超格子層１１および
Si１２が積層されている。ここで、０ｘ≠ｙ
１である。例えば、ｘ＝0.5、ｙ＝０とすれば、
１１はSi0.5Ge0.5とSiとの超格子層となる。１３
は光遮断膜、１４は変調光を示している。光はこ
の場合も第２図と同様に溝部の光導波領域９に沿
つて導波される。溝と溝との間の超格子部分に変
調光を照射することにより、その部分の屈折率が
変化し、二つの光導波路間の結合定数が変化す
る。従つて、導波される光は変調を受けることに
なる。
以上の説明では、光導波領域を形成するためSi
基板表面に溝が設けられていたが、例えばSi1-x
Gexの周囲が全てSiとなつているような埋込み型
の光導波路も可能である。また、方向性結合器型
の素子を例として説明したがマツハツエンダー干
渉器型の光変調素子あるいは受光素子など他の光
半導体素子も同様に実現されることは言うまでも
ない。
（発明の効果）
以上説明したように、本発明によれば、〔半導
体技術の特徴が十分に生かされ、薄膜の導波路を
用いた小型の〕光スイツチや光変調器等の光半導
体素子がプロセス技術の極めて進んでいるSi基板
を用いて実現されるため、安価にかつ精密に大量
生産することができる。また、同一のSi基板上
に、それらの光半導体素子を駆動させるための電
子回路を集積化することも可能であり、大規模な
集積光スイツチが実現されるので、光交換機にも
応用できその効果は極めて大である。[Table] Table 1 shows silicon (Si) and germanium (Ge)
The figure shows the lattice constant a, refractive index n, and forbidden band width Eg. The lattice constant, refractive index, and forbidden band width of Si and Ge mixed crystal Si 1-x Ge x are estimated using a linear approximation, i.e., assuming that they vary linearly with x from Si to Ge. can. for example,
When x=0.1, the refractive index of Si 0.9 Ge 0.1 can be estimated to be 3.56. Conversely, when Si 1-x Ge x is used as an optical waveguide region, the refractive index difference Δn with the surrounding Si
If approximately 0.1 is required, then x0.16 is obtained, the lattice mismatch Δa/a(Si) is approximately 0.6%, and the difference in forbidden band width ΔEg is approximately 0.07 eV. Based on these constant data, a specific example of a structure of an optical semiconductor element will be described next. FIG. 1 shows the [principle configuration] of the present invention, and is a schematic diagram of an optical directional coupler that operates as an optical switch or an optical modulator. A groove 4 is formed on the surface of the n-type Si substrate 1 at a location that will become an optical waveguide region, and on the groove 4 is formed an n-type Si and Ge mixed crystal Si 1-x Ge x 2,
and n - type Si3 are stacked. 5 and 6
is an electrode, and 7 indicates a signal power source for modulation. FIG. 2 shows a cross section taken along the line A-B in FIG. 1, and 8 is a region that has become p-type by ion implantation or diffusion. As mentioned above, if the mixed crystal ratio x of Si and Ge is about 0.16, the refractive index difference between the Si 0.84 Ge 0.16 optical waveguide 2 and Si is about 0.1, and the groove 4 as shown in Fig. 2 is provided. As a result, the optical waveguide region 9 shown by the dotted line can be easily formed. The light guided along the grooves is transferred from one groove to the other by appropriately setting the interval between the two grooves 4. In other words, a directional coupler is created. Here, for example, from the modulation signal source 7 to the electrode 5 and the p-type Si region 8
Modulate the current through the Si 1-x Ge x layer 2 between the grooves
When injected into a region, the refractive index of that region changes due to the plasma oscillation effect. Therefore, since the coupling constant between the two optical waveguide regions changes, the guided light will be modulated. FIG. 3 shows an embodiment of the present invention.
A groove 4 is provided on the surface of the Si substrate 10, and a superlattice layer 11 of Si 1-x Ge x and Si 1-y Ge y is formed on the groove 4.
Si12 is laminated. Here, 0x≠y
It is 1. For example, if x=0.5 and y=0,
11 is a superlattice layer of Si 0.5 Ge 0.5 and Si. 13
14 indicates a light blocking film, and 14 indicates modulated light. In this case as well, the light is guided along the optical waveguide region 9 of the groove as in FIG. By irradiating the superlattice portion between the grooves with modulated light, the refractive index of that portion changes, and the coupling constant between the two optical waveguides changes. Therefore, the guided light will be modulated. In the above explanation, Si is used to form the optical waveguide region.
Although grooves were provided on the substrate surface, for example, Si 1-x
A buried optical waveguide in which the entire area around Ge x is Si is also possible. Further, although the directional coupler type element has been described as an example, it goes without saying that other optical semiconductor elements such as a Matsuhatsu Ender interferometer type optical modulation element or a light receiving element can be similarly realized. (Effects of the Invention) As explained above, according to the present invention, optical semiconductor devices such as optical switches and optical modulators [which fully utilize the characteristics of semiconductor technology and are small-sized using thin-film waveguides] Since it is realized using a Si substrate with extremely advanced process technology, it can be mass-produced at low cost and with precision. It is also possible to integrate electronic circuits for driving these optical semiconductor elements on the same Si substrate, making it possible to realize large-scale integrated optical switches, which can also be applied to optical switching equipment. The effect is extremely large.
第１図は本発明の〔原理的構成を示す〕斜視
図、第２図は第１図Ａ−Ｂ部分の断面模式図、第
３図は本発明の実施例の断面模式図である。
１……ｎ型Si基板、２……Si1-xGex層、３……
n-Si層、４……溝、５，６……電極、７……変調
信号源、８……ｐ型Si、９……光導波領域、１０
……Si基板、１１……Si1-xGexとSi1-yGeyとの超
格子層、１２……Si層、１３……光遮断膜、１４
……変調光。
FIG. 1 is a perspective view showing the basic structure of the present invention, FIG. 2 is a schematic cross-sectional view taken along line AB in FIG. 1, and FIG. 3 is a schematic cross-sectional view of an embodiment of the present invention. 1...n-type Si substrate, 2...Si 1-x Ge x layer, 3...
n - Si layer, 4... Groove, 5, 6... Electrode, 7... Modulation signal source, 8... P-type Si, 9... Optical waveguide region, 10
...Si substrate, 11...Superlattice layer of Si 1-x Ge x and Si 1-y Ge y , 12... Si layer, 13... Light blocking film, 14
...Modulated light.
Claims (1)
以上のシリコンとゲルマニウムの混晶を用いた超
格子により光導波領域が形成されていることを特
徴とする光半導体素子。 ２ 前記光導波領域が混晶比の異なるシリコンと
ゲルマニウムの混晶の超格子から成ることを特徴
とする特許請求の範囲第１項記載の光半導体素
子。[Claims] 1. Germanium composition is 16% on a silicon substrate.
An optical semiconductor device characterized in that an optical waveguide region is formed by a superlattice using a mixed crystal of silicon and germanium as described above. 2. The optical semiconductor device according to claim 1, wherein the optical waveguide region is composed of a superlattice of mixed crystals of silicon and germanium having different mixed crystal ratios.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP17014484A JPS6147910A (en) | 1984-08-15 | 1984-08-15 | Optical semiconductor element |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP17014484A JPS6147910A (en) | 1984-08-15 | 1984-08-15 | Optical semiconductor element |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPS6147910A JPS6147910A (en) | 1986-03-08 |
| JPH0572561B2 true JPH0572561B2 (en) | 1993-10-12 |
Family
ID=15899483
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP17014484A Granted JPS6147910A (en) | 1984-08-15 | 1984-08-15 | Optical semiconductor element |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPS6147910A (en) |
Families Citing this family (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS61198212A (en) * | 1985-02-28 | 1986-09-02 | Tokyo Inst Of Technol | Optical circuit function element |
| US4861129A (en) * | 1987-04-17 | 1989-08-29 | Hoechst Celanese Corp. | Inorganic-organic composite compositions exhibiting nonlinear optical response |
| JP2901333B2 (en) * | 1990-10-12 | 1999-06-07 | 日本電気株式会社 | Active wavelength selective semiconductor device |
| JP2006133723A (en) * | 2004-10-08 | 2006-05-25 | Sony Corp | Light guide module and optoelectric hybrid device, and their manufacturing method |
Citations (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS4922952A (en) * | 1972-06-19 | 1974-02-28 |
-
1984
- 1984-08-15 JP JP17014484A patent/JPS6147910A/en active Granted
Patent Citations (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS4922952A (en) * | 1972-06-19 | 1974-02-28 |
Also Published As
| Publication number | Publication date |
|---|---|
| JPS6147910A (en) | 1986-03-08 |
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