JP2666888B2 - Optical device manufacturing method - Google Patents
Optical device manufacturing methodInfo
- Publication number
- JP2666888B2 JP2666888B2 JP808295A JP808295A JP2666888B2 JP 2666888 B2 JP2666888 B2 JP 2666888B2 JP 808295 A JP808295 A JP 808295A JP 808295 A JP808295 A JP 808295A JP 2666888 B2 JP2666888 B2 JP 2666888B2
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- Prior art keywords
- light
- thin film
- conductive thin
- optical window
- optical
- Prior art date
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- Optical Integrated Circuits (AREA)
- Light Receiving Elements (AREA)
Description
【０００１】[0001]
【産業上の利用分野】本発明は通信、情報処理分野にお
いて必要となる光素子、すなわち光信号を電気信号に変
換する受光素子、あるいは逆に電気信号を光信号に変換
する発光素子の製造方法上の改良に関する。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for manufacturing an optical element required in the field of communication and information processing, that is, a light receiving element for converting an optical signal into an electric signal or a light emitting element for converting an electric signal into an optical signal. Regarding the above improvement.
【０００２】[0002]
【従来の技術】本書では、受光素子における光信号を電
気信号に変換する機能も、また逆に発光素子における電
気信号を光信号に変換する機能も、これらをまとめて共
に「光電変換機能」と称するが、従来提供されている光
素子の中には、図６に符号50によって示すような断面構
造を必要とするものがある。すなわち、受光または発光
を司る光電変換機能部11の一表面上の一部の所定面積領
域が入射光を受けるか発光を出力する所定幅Ｗの光学窓
13となっており、その両側に光非透過導電性薄膜12，12
が形成され、その上に一連に光学窓保護絶縁層51が設け
られる。2. Description of the Related Art In this document, the function of converting a light signal in a light receiving element into an electric signal and the function of converting an electric signal in a light emitting element into an optical signal are collectively referred to as a "photoelectric conversion function". It should be noted that some of the conventionally provided optical elements require a cross-sectional structure as indicated by reference numeral 50 in FIG. That is, an optical window having a predetermined width W for receiving incident light or outputting light emission in a part of a predetermined area on one surface of the photoelectric conversion function unit 11 which controls light reception or light emission.
13 with light-impermeable conductive thin films 12 and 12 on both sides.
Is formed, and an optical window protection insulating layer 51 is provided thereon in a series.
【０００３】例えば受光素子においてこのような構造の
具体例を探すと、「IEEE Journal ofQUANTUM ELECTORONI
CS, Vol.28, pp.2358-2368, 1992」に開示された受光素
子がある。これは一般にＭＳＭ（金属／半導体／金属）
型の受光素子と呼ばれ、光非透過導電性薄膜12，12を一
対の電圧印加部材12，12として利用し、これらの間に適
当な電圧を印加した状態で光学窓13に光が入射すると、
光吸収部材として構成された光電変換機能部11中に励起
キャリア（電子及び正孔）が発生し、正孔は相対的に負
電位になる電圧印加部材12の方に、また電子は相対的に
正電位になる電圧印加部材12の方にそれぞれ引き込ま
れ、これにより一対の電圧印加部材12，12を介し光伝導
電流（光検出電流）が流れて、入射光のあったことが検
出される。実際にも、上記文献にて開示されている素子
では、パルス応答での出力半値全幅が 870fsと、それま
での従来素子に比せばかなりな高速動作が得られてい
る。また、この文献中では保護絶縁膜51は開示されてい
ないが、実用的な素子とするために従来の考え方に従い
こうした保護絶縁膜51を形成しようとすると、図６に示
されたような構造となる。For example, a search for a specific example of such a structure in a light receiving element is described in “IEEE Journal of QUANTUM ELECTORONI”.
CS, Vol. 28, pp. 2358-2368, 1992 ". This is generally MSM (metal / semiconductor / metal)
When the light enters the optical window 13 with an appropriate voltage applied between the light-impermeable conductive thin films 12 and 12 as a pair of voltage applying members 12 and 12 ,
Excited carriers (electrons and holes) are generated in the photoelectric conversion function unit 11 configured as a light absorbing member, and the holes are relatively directed to the voltage applying member 12 at which the potential becomes relatively negative. The voltage is applied to the voltage applying member 12 which becomes a positive potential, whereby a photoconductive current (light detection current) flows through the pair of voltage applying members 12 and 12, and the presence of incident light is detected. In fact, in the device disclosed in the above-mentioned document, the full width at half maximum of the output in the pulse response is 870 fs, which is considerably higher than that of the conventional device. Further, although the protective insulating film 51 is not disclosed in this document, in order to form such a protective insulating film 51 according to the conventional concept in order to make it a practical device, the structure shown in FIG. Become.
【０００４】[0004]
【発明が解決しようとする課題】しかるに、従来、図６
に示したような光素子を作製する場合、光電変換機能部
11の上に形成した光非透過導電性薄膜12の所定面積領域
を既存のリソグラフィ技術により除去し、光学窓13とな
る部分を露呈し、領域的に確定させた後、次の工程でス
パッタリング等の全面蒸着法により、光学窓保護絶縁膜
51を一連に形成していた。However, conventionally, FIG.
When producing an optical element as shown in the above, the photoelectric conversion function unit
A predetermined area region of the light-impermeable conductive thin film 12 formed on 11 is removed by an existing lithography technique, a portion to be an optical window 13 is exposed, and the region is fixed. Optical window protective insulating film
51 were formed in series.
【０００５】しかし、スパッタリング等を行なう高真空
蒸着装置は高価であり、これを採用しないで済めばそれ
に越したことはない。また、光学窓13の形成（領域確
定）のための光非透過導電性薄膜12のリソグラフィ工程
と光学窓13を保護するための保護絶縁膜51の形成工程と
は別の素工程であるが、これがもし、単一素工程で同時
に行なえるとしたら、それは光素子製造ライン上の大い
なる簡略化に繋がる。[0005] However, a high-vacuum vapor deposition apparatus for performing sputtering or the like is expensive, and if it is not used, it will not be better. Further, the lithography process of the light non-transmissive conductive thin film 12 for forming the optical window 13 (determining the region) and the forming process of the protective insulating film 51 for protecting the optical window 13 are separate element processes. If this can be done simultaneously in a single elementary process, it will lead to great simplification on the optical device manufacturing line.
【０００６】さらに、既存の微細加工技術では、電子ビ
ーム露光技術等、従来においては比較的高精度な微細加
工技術を適用しても、光非透過導電性薄膜12に開けられ
る開口の幅Ｗは 300nm程度までであり、これ以下にまで
微小な幅Ｗに光学窓13を精度良く形成することは極めて
困難である。Further, in the existing fine processing technology, even if a relatively high-precision fine processing technology such as an electron beam exposure technology is applied in the past, the width W of the opening formed in the light non-transmissive conductive thin film 12 can be increased. It is extremely difficult to form the optical window 13 with a very small width W up to about 300 nm.
【０００７】素子特性的に見ても、全面蒸着における面
内蒸着膜厚の不均一性により素子特性にばらつきが出た
り、誘電体蒸着による高周波特性劣化の問題等もある。
光学窓上に形成される絶縁膜の特性としても、光学窓が
微細化して来るとその上に高耐圧、高品質なものを作る
のは難しい。In terms of device characteristics, there are problems such as unevenness in device characteristics due to non-uniformity of the in-plane deposition film thickness in the entire surface deposition and deterioration of high frequency characteristics due to dielectric deposition.
Regarding the characteristics of the insulating film formed on the optical window, it is difficult to produce a high withstand voltage and high quality on the optical window as the window becomes finer.
【０００８】本発明は基本的にはこうした点に鑑みてな
されたもので、光学窓の領域的な確定と、当該光学窓の
表面を覆う保護部材との形成を同一の素工程で行ない得
るような製造方法の提供を主たる目的とし、さらに望ま
しくは、上述した種々の欠点が解消されるか少なくとも
緩和され、また要すれば従来よりも微細幅の光学窓をも
形成し得るような製造方法を提供せんとするものであ
る。The present invention has been basically made in view of the above points, and is intended to determine the area of an optical window and to form a protective member covering the surface of the optical window in the same elementary process. The main object of the present invention is to provide a manufacturing method which can eliminate or at least mitigate the above-mentioned various drawbacks, and which can also form an optical window having a finer width than before, if necessary. It will not be provided.
【０００９】[0009]
【課題を解決するための手段】本発明は上記目的を達成
するため、 (a) 発光または受光を司る光電変換機能部の一表面上に
光非透過導電性薄膜を形成する工程と； (b) 光非透過導電性薄膜の一部の領域を変成することに
より、所定の幅と長さを有する光透過性の光学窓保護絶
縁構造体を形成すると同時に、当該形成される光学窓保
護絶縁構造体の下の光電変換機能部表面における光学窓
の領域確定も行なう工程と； を含んで成る光素子の製造方法を提案する。In order to achieve the above object, the present invention provides: (a) a step of forming an optically non-transmissive conductive thin film on one surface of a photoelectric conversion function part for emitting or receiving light; A) forming a light-transmitting optical window protection insulating structure having a predetermined width and length by modifying a part of the region of the light-impermeable conductive thin film; A step of also determining the area of the optical window on the surface of the photoelectric conversion function part under the body.
【００１０】ここで、上記の光非透過導電性薄膜は、金
属または合金であっても良いし、半導体（一般に半絶縁
性と呼ばれるものも含む）であっても良い外、内部に半
導体超格子構造を含むものであっても本発明の適用を受
けることができる。Here, the light non-transmissive conductive thin film may be a metal or an alloy, or may be a semiconductor (including what is generally called semi-insulating), and also has a semiconductor superlattice inside. The present invention can be applied to a structure including a structure.
【００１１】また、本発明の特定の態様としては、上記
の光非透過導電性薄膜の変成は酸化であることを提案
し、特にこの場合、当該酸化は走査プローブ加工装置に
よりなすことも提案する。Further, as a specific embodiment of the present invention, it is proposed that the transformation of the light-impermeable conductive thin film is oxidation, and in this case, in particular, that the oxidation is performed by a scanning probe processing apparatus. .
【００１２】本発明のまた別な態様では、光非透過導電
性薄膜において上記変成される一部の領域は、当該光非
透過導電性薄膜にあって互いに離間した複数個所にあっ
ても良い。In still another aspect of the present invention, the partially modified region in the light-impermeable conductive thin film may be located at a plurality of locations in the light-impermeable conductive thin film that are separated from each other.
【００１３】さらに、より下位の構成として、本発明で
は、 ・上記の光電変換機能部は受光機能を司る光吸収部材で
あり、 ・上記変成されなかった光非透過導電性薄膜部分は光吸
収部材に対し電圧を印加する電圧印加部材として機能
し、 ・上記の光学窓保護絶縁構造体は光吸収部材に光を導入
する光ガイド部材として機能すること、 を特徴とする光素子の製造方法も提案する。[0013] Further, the present invention provides, as a lower-level structure, the following: In the present invention, the above-mentioned photoelectric conversion function part is a light absorbing member which performs a light receiving function; The optical window protective insulating structure functions as a light guide member for introducing light into the light absorbing member, and a method for manufacturing an optical element, characterized in that: I do.
【００１４】なお、上記したいずれの態様の場合にも、
本発明により形成される立体構造体としての光学窓保護
絶縁構造体の厚さは、望ましくはその両側にあって変成
されずに残る光非透過導電性薄膜の厚さよりも厚くする
と、当該変成されずに残る光非透過導電性薄膜を一対の
電圧印加部材として利用する場合、それらの間の沿面距
離を長くすることができるので、結果として絶縁破壊に
対する耐性を高めることができる。In any of the above embodiments,
The thickness of the optical window protective insulating structure as a three-dimensional structure formed according to the present invention is desirably thicker than the thickness of the light-impermeable conductive thin film remaining on both sides thereof without being denatured. When the remaining light-impermeable conductive thin film is used as a pair of voltage applying members, the creepage distance between them can be increased, and as a result, the resistance to dielectric breakdown can be increased.
【００１５】[0015]
【実施例】図１には、本発明の光素子製造方法の基本的
な実施例が示されている。図中において、既に図６に即
し説明した従来素子50の各構成要素に付した符号は、理
解をたやすくするため、本実施例中でも対応するものに
同じく付している。また、後述する他の実施例において
も、対応する構成要素には同じ符号を付す。FIG. 1 shows a basic embodiment of the optical device manufacturing method of the present invention. In the figure, the reference numerals given to the respective components of the conventional element 50 already described with reference to FIG. 6 are also given to the corresponding elements in the present embodiment in order to facilitate understanding. Also, in other embodiments described later, corresponding components are denoted by the same reference numerals.
【００１６】まず、図１(A) に示すように、受光または
発光を司る光電変換機能部11の一表面上に一連に、光非
透過性で導電性の薄膜12を形成する。ただし、光電変換
機能部11の具体的な内部構成自体は本発明が直接に規定
するものではなく、任意既存のデバイス構造原理に従っ
て構築されたものであって良い。既に説明した従来のＭ
ＳＭ型受光素子のような場合には、この光電変換機能部
11は光吸収部材として機能するが、物としては半絶縁性
GaAs基板等、単なる半導体バルク基板であることもあ
る。また、光非透過導電性薄膜12は適当なる金属（合金
を含む）の外、半導体であっても良いし、デバイス構築
上の必要から超格子構造を含む半導体等であっても良
い。少なくとも受光素子であれば検出対象の光に対し、
また発光素子であれば出力光に対し、透過性がないか極
めて乏しく、しかし電気的には有意の導電性を有するも
のであれば、なべて本発明の適用対象とすることができ
る。First, as shown in FIG. 1A, a light non-transmissive and conductive thin film 12 is formed on one surface of a photoelectric conversion function portion 11 which controls light reception or light emission. However, the specific internal configuration of the photoelectric conversion function unit 11 is not directly defined by the present invention, but may be configured according to any existing device structure principle. The conventional M already described
In the case of an SM type light receiving element, this photoelectric conversion function unit
11 functions as a light absorbing member, but is semi-insulating as an object
It may be a simple semiconductor bulk substrate such as a GaAs substrate. In addition, the light-impermeable conductive thin film 12 may be a semiconductor other than a suitable metal (including an alloy), or may be a semiconductor having a superlattice structure if necessary for device construction. At least for the light receiving element,
In addition, a light-emitting element having no or very low transmittance with respect to output light, but any element having significant electrical conductivity can be applied to the present invention.
【００１７】図１(A) に示す上記のような出発構造に対
し、次いで図１(B) に示すように、最終的に光学窓を形
成したい形成予定領域13’に対応する光非透過導電性薄
膜12の一部の領域の物性を変成し、光透過性を有する
（すなわち検出対象または発光対象の光に対して透明で
あるか少なくとも半透明の）立体構造としての絶縁体を
形成する。これには、望ましくは走査プローブ加工装置
を利用しての酸化処理がある。走査プローブ加工装置と
は、トンネル顕微鏡（ＳＴＭ：Scanning TunnelMicrosc
ope）とか原子間力顕微鏡（ＡＦＭ：Atomic Force Micr
oscope)を試料加工装置として利用するもので、基板に
相当する光電変換機能部11上に形成された光非透過導電
性薄膜12に対し、例えばＳＴＭの走査プローブＰの尖端
を近付け、電源Ｖにより当該プローブ尖端と光非透過導
電性薄膜12間に高電界を印加しながらプローブＰを矢印
Ｓで示すように相対走査すると、その軌跡に従い光非透
過導電性薄膜12が電気化学反応によって変成、酸化さ
れ、光透過性を有する変成絶縁細線15’が形成される。
本出願人においても、こうした手法により、GaAs上に最
高分解能で18nm幅の酸化チタン細線の形成に成功してい
る。ＡＦＭを用いても同様の結果が得られる。なお、本
発明には直接の関係はないが、ＡＦＭの場合、加工対象
薄膜は導電性薄膜に限定されない。In contrast to the above-mentioned starting structure shown in FIG. 1 (A), as shown in FIG. 1 (B), a light-impermeable conductive material corresponding to a region 13 'to be finally formed with an optical window is to be formed. The physical properties of some regions of the conductive thin film 12 are altered, and an insulator is formed as a three-dimensional structure having light transmittance (that is, transparent or at least translucent to light to be detected or emitted). This includes an oxidation treatment, preferably utilizing a scanning probe processing device. The scanning probe processing device is a scanning microscope (STM: Scanning TunnelMicrosc).
ope) or atomic force microscope (AFM)
A probe is used as a sample processing apparatus. For example, the tip of a scanning probe P of an STM is brought close to a light non-transmissive conductive thin film 12 formed on a photoelectric conversion function section 11 corresponding to a substrate, and a power supply V is used. When the probe P is relatively scanned as shown by an arrow S while applying a high electric field between the probe tip and the light-impermeable conductive thin film 12, the light-impermeable conductive thin film 12 is transformed and oxidized by an electrochemical reaction according to the locus. As a result, a modified insulating thin wire 15 'having light transmittance is formed.
The present applicant has also succeeded in forming a titanium oxide fine line with a maximum resolution of 18 nm on GaAs by such a method. Similar results are obtained using AFM. Although there is no direct relationship with the present invention, in the case of AFM, the thin film to be processed is not limited to a conductive thin film.
【００１８】このようにして変成絶縁細線15’を所定の
長さに形成し終えると、図１(C) に示すように、所定の
幅と長さを有する光透過性の立体構造体である光学窓保
護絶縁構造体15の形成と、この構造体の下の光電変換機
能部の表面における光学窓13の領域の確定とが同一の素
工程で行なわれたことになる。従来におけるように、光
学窓の形成素工程の後工程として、別途に光学窓を保護
する保護膜を全面蒸着する必要はなくなり、工程の簡略
化が果たされる。When the modified insulated wire 15 'is formed to a predetermined length in this way, as shown in FIG. 1C, a light-transmitting three-dimensional structure having a predetermined width and length is obtained. This means that the formation of the optical window protection insulating structure 15 and the determination of the area of the optical window 13 on the surface of the photoelectric conversion function portion below this structure were performed in the same elementary process. As in the related art, it is not necessary to separately deposit the entire surface of a protective film for protecting the optical window as a post-process of the optical window forming element process, thereby simplifying the process.
【００１９】また、本発明に従って作製された光素子10
では、光学窓保護絶縁構造体15の両側にあって変成され
ずに残った光非透過導電性薄膜12，12を一対の電圧印加
部材として利用する場合、当該一対の電圧印加部材12，
12間に光学窓保護絶縁構造体15が絶縁構造体として介在
するため、沿面距離が長くなって絶縁破壊に対する耐性
が高まる。もちろん、光学窓保護絶縁構造体15の厚みが
ある程度以上に厚い程にその絶縁能力も高まる。従っ
て、従来と同程度の離間距離Ｗで良ければ一対の電圧印
加部材12，12間にはより高い電圧を印加でき、逆に同じ
程度の印加電圧であっても要すれば一対の電圧印加部材
12，12間をもっと近付けることで光電変換機能部11の表
面近傍における電界強度を高めることができる。これ
は、既述したＭＳＭ型受光素子の作製に本発明を適用し
た場合に極めて有利に働く。特に、光非透過導電性薄膜
12の変成に走査プローブ加工装置を利用するならば、光
学窓13の幅Ｗ（すなわち一対の電圧印加部材12，12間の
離間距離Ｗ）は最高で十数nmにまで短縮でき、しかも、
そのような状態でも同時に酸化形成される光学窓保護絶
縁構造体15は特性の良好な高耐圧、高品質絶縁体とな
る。そこで、図２に即し、より具体的な実施例として、
本発明の製造方法でＭＳＭ型受光素子を作製した場合に
つき説明する。Further, the optical device 10 manufactured according to the present invention
In the case where the light non-transmissive conductive thin films 12 and 12 remaining on both sides of the optical window protective insulating structure 15 without being denatured are used as a pair of voltage applying members, the pair of voltage applying members 12 and 12 are used.
Since the optical window protective insulating structure 15 is interposed between the 12 as an insulating structure, the creepage distance is increased and the resistance to dielectric breakdown is increased. Of course, as the thickness of the optical window protection insulating structure 15 is greater than a certain level, the insulating ability thereof is increased. Therefore, a higher voltage can be applied between the pair of voltage applying members 12 and 12 if the same separation distance W as in the related art is sufficient.
The electric field strength in the vicinity of the surface of the photoelectric conversion function unit 11 can be increased by making the distance between 12 and 12 closer. This works extremely advantageously when the present invention is applied to the fabrication of the above-described MSM light receiving element. In particular, light-impermeable conductive thin films
If a scanning probe processing apparatus is used for the transformation of 12, the width W of the optical window 13 (that is, the separation distance W between the pair of voltage applying members 12, 12) can be reduced to a maximum of over ten nm, and
Even in such a state, the optical window protective insulating structure 15 formed by oxidation at the same time becomes a high withstand voltage and high quality insulator having good characteristics. Therefore, according to FIG. 2, as a more specific embodiment,
A case where an MSM type light receiving element is manufactured by the manufacturing method of the present invention will be described.
【００２０】まず、図２(A) に示すように、光電変換機
能部11に相当する光吸収部材11として半絶縁性GaAs基板
11を選び、この上に、光非透過導電性薄膜12としてチタ
ン薄膜12を蒸着した。このチタン薄膜12の所定部分の表
面にＳＴＭの走査プローブＰを近付け、図２(B) に示す
ように大気環境下（すなわち水分を含む環境下）でプロ
ーブＰとチタン薄膜12間に5Vの電位を印加し、トンネル
電流を流しながら図面紙面と直交する走査方向に沿って
プローブＳを相対走査した。このとき、プローブ走査速
度は形成される酸化チタン細線15の幅が100nm になるよ
うにした。ちなみに印加電圧や走査速度を調整すること
により、形成される酸化チタンの幅や厚みをかなり自由
に調整することができる。広幅の酸化チタン細線15を得
たい場合には、横方向にプローブＰをずらしながら繰返
し走査を行なえば良い。First, as shown in FIG. 2A, a semi-insulating GaAs substrate is used as a light absorbing member 11 corresponding to the photoelectric conversion function portion 11.
11, a titanium thin film 12 was deposited thereon as a light non-transmissive conductive thin film 12. An STM scanning probe P is brought close to the surface of a predetermined portion of the titanium thin film 12, and a potential of 5 V is applied between the probe P and the titanium thin film 12 under an atmospheric environment (ie, under an environment containing moisture) as shown in FIG. , And the probe S was relatively scanned along a scanning direction orthogonal to the plane of the drawing while flowing a tunnel current. At this time, the scanning speed of the probe was set so that the width of the formed titanium oxide fine wire 15 was 100 nm. Incidentally, by adjusting the applied voltage and the scanning speed, the width and thickness of the formed titanium oxide can be adjusted quite freely. When it is desired to obtain a wide titanium oxide thin wire 15, the scanning may be repeatedly performed while shifting the probe P in the horizontal direction.
【００２１】このようにして形成された酸化チタン細線
15は、既述した光学窓保護絶縁構造体15となり、同時に
その下に、光学窓（本図では幅狭なため、図面を簡明化
する意味から符号を付していない）の領域が確定的に形
成されると共に、その両側にあって酸化されずに残った
チタン薄膜部分12，12は一対の電圧印加部材12，12とな
る。換言すると、この手法は、光学窓の領域確定のみな
らず、一対の電圧印加部材12，12とその間に設けられる
べき光学窓保護絶縁構造体15とを一遍に作る合理的な手
法とも言える。The titanium oxide fine wire thus formed
Reference numeral 15 designates the optical window protection insulating structure 15 described above, and at the same time, the area of the optical window (not denoted by a reference numeral for simplicity of the drawing in this drawing, which is narrow in this drawing) is deterministic. The titanium thin film portions 12, 12 remaining on both sides thereof without being oxidized become a pair of voltage applying members 12, 12. In other words, this method can be said to be a rational method not only for determining the area of the optical window but also for uniformly forming the pair of voltage applying members 12 and the optical window protection insulating structure 15 to be provided therebetween.
【００２２】この後、図２(C) に示す通り、必要に応じ
外部回路と電気的接続を取るのに便利なように、一対の
電圧印加部材12，12の所望の面積部分上に例えばTi／Au
取り付け電極14，14を形成する。さらに、実用的な素子
とするために、図２(D) に示すように、電圧印加部材1
2，12と光学窓保護絶縁構造体15を含むストライプと平
行に例えばTi／Au接地用電極14’，14’を形成する。各
ストライプの幅と隣接するストライプ間の寸法は本試作
素子ではそれぞれ 5μm とした。これにより、一対の電
圧印加部材12，12の一方に対してはバイアス電圧Vbを印
加するバイアス線Lbを、他方の電圧印加部材12に対して
は抵抗Ｒで模式的に示した負荷Ｒへの信号線Lrを接続す
ることができ、その脇でシールド構造を形成する一対の
接地用電極14’，14’にはそれぞれ接地線Leを接続する
ことができる。Thereafter, as shown in FIG. 2 (C), for example, Ti is placed on a desired area of the pair of voltage applying members 12 and 12 so that it is convenient to make an electrical connection with an external circuit if necessary. / Au
The mounting electrodes 14 are formed. Further, in order to make the element practical, as shown in FIG.
For example, Ti / Au ground electrodes 14 ′, 14 ′ are formed in parallel with the stripes including the optical window protection insulating structures 15, 2 and 12. The width of each stripe and the dimension between adjacent stripes were 5 μm in this prototype device. As a result, the bias line Lb for applying the bias voltage Vb is applied to one of the pair of voltage applying members 12, 12 and the load R is schematically indicated by the resistor R to the other voltage applying member 12. A signal line Lr can be connected, and a ground line Le can be connected to a pair of grounding electrodes 14 ', 14' forming a shield structure beside the signal line Lr.
【００２３】作製した試作素子の評価には電気光学サン
プリング法を用いた。これは、被測定回路上に置かれた
電気光学結晶中の電界変化に比例したレーザ光の偏光変
化を検出することにより、電気信号をフェムト秒(fs)領
域の時間分解能で計測し得る手法であるが、本試作素子
10の評価には図３に示すような測定システムを構築し
た。An electro-optic sampling method was used to evaluate the fabricated prototype device. This is a method that can measure electrical signals with time resolution in the femtosecond (fs) region by detecting the polarization change of laser light in proportion to the electric field change in the electro-optic crystal placed on the circuit under test. There is a prototype element
For the evaluation of 10, a measurement system as shown in FIG. 3 was constructed.
【００２４】光源はアルゴンイオンレーザ21から入力光
を受ける衝突モード同期（ＣＰＭ：Colliding Pulse Mo
de-locked)色素レーザ22であって、レーザ出力は約10m
W、出力パルス幅は40fs、波長は620nm である。この波
長620nm の光に対し、試作素子における酸化チタン製の
光学窓保護絶縁構造体15は十分な透明性を示して光ガイ
ド部材として機能し、かつ電気的には満足な絶縁体であ
る。ＣＰＭ色素レーザ22の出力はビームスプリッタ23に
より９：１に分割し、前者を励起ビームIp、後者をサン
プリングビームIsとして、励起ビームIpをサンプリング
ビームIs側との光路差調整用の可変遅延装置32に通した
後、本発明素子の光学窓保護絶縁構造体15に入射させ、
一方、サンプリングビームIsは偏光方向調整のための2/
λ波長板24を介し偏光子25に入射させた後、電気光学
（ＥＯ：Electro-Optical)プローブ31に入射させる。Ｅ
Ｏプローブ31は電気光学係数が35.8pm/VのLiTaO3板で、
試作受光素子側に接する結晶裏面には誘電体多層膜の反
射コーティングが施され、大きさは縦 300μm 、横 250
μm 、厚さ50μm である。また、このＥＯプローブ31の
結晶方位とサンプリングビームIsの偏光方向は、ストラ
イプ線路上における横方向電界に対して感度が最大にな
るように設定した。The light source is a collision mode locked (CPM) which receives input light from the argon ion laser 21.
de-locked) dye laser 22, laser output about 10m
W, output pulse width is 40fs, and wavelength is 620nm. With respect to the light having the wavelength of 620 nm, the optical window protective insulating structure 15 made of titanium oxide in the prototype device exhibits sufficient transparency, functions as a light guide member, and is an electrically satisfactory insulator. The output of the CPM dye laser 22 is split 9: 1 by the beam splitter 23, and the former is used as the excitation beam Ip and the latter is used as the sampling beam Is, and the excitation beam Ip is used as a variable delay device 32 for adjusting the optical path difference with the sampling beam Is. After passing through, incident on the optical window protection insulating structure 15 of the element of the present invention,
On the other hand, the sampling beam Is is 2 /
After being incident on the polarizer 25 via the λ wavelength plate 24, the incident light is incident on an electro-optical (EO) probe 31. E
The O probe 31 is a LiTaO 3 plate having an electro-optic coefficient of 35.8 pm / V,
The reflective surface of the dielectric multilayer film is coated on the backside of the crystal that is in contact with the prototype photodetector, and is 300 μm long and 250 μm wide.
μm and a thickness of 50 μm. Further, the crystal orientation of the EO probe 31 and the polarization direction of the sampling beam Is are set so that the sensitivity to the horizontal electric field on the stripe line is maximized.
【００２５】ＥＯプローブ31中へのしみ出し電界により
位相変調を受けて反射されたサンプリングビームIsはソ
レイユ・バビネ位相補償板26により位相補償を受けた
後、偏光ビームスプリッタ27を介し一対の受光器28a,b
により強度変調に置き換えられて受光され、受光器出力
は差動増幅器29を介した後、試作素子に印加すると同じ
1MHzの周期でロックイン増幅器34によりロックイン検波
される。The sampling beam Is, which has been phase-modulated and reflected by the electric field leaking into the EO probe 31, has been phase-compensated by a Soleil-Babinet phase compensating plate 26 and then passed through a polarizing beam splitter 27 to a pair of photodetectors. 28a, b
The light is replaced by intensity modulation, and the light is received.
Lock-in detection is performed by the lock-in amplifier 34 at a cycle of 1 MHz.
【００２６】ロックイン増幅器34の出力に基づきプロッ
トされた測定結果は図４に示されている。測定は試作素
子10から70μm 離れた地点で行なったが、電気パルスの
半値全幅としては570fs を得るに成功した。これは 3dB
帯域として790GHzに相当し、この種の光導電型受光素子
として、間違いなく現時点における世界最高速の値であ
る。The measurement results plotted based on the output of the lock-in amplifier 34 are shown in FIG. The measurement was performed at a point 70 μm away from the prototype device 10, and the full width at half maximum of the electric pulse was 570fs. This is 3dB
It corresponds to a band of 790 GHz, and is undoubtedly the world's fastest value of this type of photoconductive photodetector at present.
【００２７】以上のように、本発明に従うと、光学窓の
領域確定と光学窓の保護用構造体の形成が単一素工程で
同時に行なえるという基本的な効果に加え、例えば 100
nm程度というように、対象光波長以下の極めて微細な寸
法の光学窓の形成とその上の高耐圧、高品質保護絶縁構
造体15の形成とが可能になる。その結果、ＭＳＭ型受光
素子等では高速、高感度な素子を作製し得る。As described above, according to the present invention, in addition to the basic effect that the area of the optical window is determined and the structure for protecting the optical window can be formed simultaneously in a single elementary process, for example, 100
It is possible to form an optical window having an extremely fine dimension of not more than the wavelength of the target light, such as about nm, and to form a high-voltage, high-quality protective insulating structure 15 thereon. As a result, a high-speed, high-sensitivity element can be manufactured as an MSM-type light receiving element or the like.
【００２８】すなわち、一対の電圧印加部材12，12間に
規定される光学窓13の幅Ｗを検出対象の光の波長以下と
すると、光吸収部材11に入射する光は近接光電界（エバ
ネッセントな光電界）で表されることになり、光吸収部
材11の表面近傍のみ、光電界強度が高くなって、入射光
は光吸収部材11の当該表面近傍で吸収されることにな
る。そこで、本発明により高耐圧、高品質絶縁構造体15
が設けられることにより一対の電圧印加部材12，12間に
従来よりも大きな電圧を印加できるようになった素子に
おいては、光の入射により光吸収部材11の表面近傍に発
生した励起キャリア（電子及び正孔）は、電圧印加部材
12，12に近いことで内部よりも高電界強度になっている
表面電界により、電子は相対的に正電位側の電圧印加部
材12に、また正孔は相対的に負電位側の電圧印加部材12
に、それぞれ高速で引き抜かれるようになる。これは言
い換えれば、従来よりも高速な光電変換動作（光検出動
作）が可能なことを意味し、また、高電圧の印加により
励起キャリアの寿命よりも高速に引き抜くことができも
するので、当該励起キャリア対の再結合の影響も低減す
ることができ、これも高感度化、高出力化に寄与する。
しかし、この効果を逆に言うと、従来素子における 300
nm程度よりも、検出対象の光の波長以下という限定の下
で一対の電圧印加部材12，12間の離間距離Ｗをむしろ大
きくしても、本発明素子では絶縁破壊の恐れが少ないの
で当該一対の電圧印加部材12，12間にはより大きな電圧
を印加できるため、結果として従来素子より高速、高感
度な受光素子を提供できるとも言える。そして、この場
合には製造工程に係る負担が軽くなり、光学窓保護絶縁
構造体15の形成に上記した走査プローブ加工法を援用し
ても良いことはもちろんである（例えば既述のように、
プローブＰの走査を横方向に少しずらしながら繰返すこ
とで任意の広幅酸化線路を描くこともできる）が、そう
でなく、他の選択酸化法等を利用することもできる。That is, if the width W of the optical window 13 defined between the pair of voltage applying members 12, 12 is set to be equal to or less than the wavelength of the light to be detected, the light incident on the light absorbing member 11 will be in the proximity optical electric field (evanescent electric field). Therefore, the intensity of the light electric field is increased only near the surface of the light absorbing member 11, and the incident light is absorbed near the surface of the light absorbing member 11. Therefore, according to the present invention, a high withstand voltage and high quality insulating structure 15 is provided.
Is provided, the element capable of applying a higher voltage between the pair of voltage applying members 12 and 12 than in the prior art has the excited carriers (electrons and electrons) generated near the surface of the light absorbing member 11 due to the incidence of light. Hole) is a voltage applying member
Due to the surface electric field that is higher than the inside due to the proximity to 12, 12, electrons are applied to the voltage applying member 12 on the relatively positive potential side, and holes are applied to the voltage applying member on the relatively negative potential side. 12
In each case, they will be pulled out at high speed. In other words, this means that the photoelectric conversion operation (light detection operation) can be performed at a higher speed than in the past, and it is possible to extract the excited carriers faster than the life of the excited carriers by applying a high voltage. The effect of the recombination of the excited carrier pair can also be reduced, which also contributes to higher sensitivity and higher output.
However, to put this effect in reverse, the 300
Even if the distance W between the pair of voltage applying members 12, 12 is rather large under the limitation that the wavelength is smaller than the wavelength of the light to be detected than about nm, the element of the present invention is less likely to cause dielectric breakdown. Since a larger voltage can be applied between the voltage applying members 12 and 12, it can be said that as a result, a light receiving element with higher speed and higher sensitivity than the conventional element can be provided. In this case, the burden on the manufacturing process is reduced, and the above-described scanning probe processing method may be used to form the optical window protection insulating structure 15 (for example, as described above,
An arbitrary wide oxidized line can be drawn by repeating the scanning of the probe P while being slightly shifted in the horizontal direction), but other selective oxidizing methods and the like can also be used.
【００２９】図５は本発明の他の適用例を示している。
説明するに、光非透過導電性薄膜12には、図示の場合は
二つしか示していないが二つ以上の光学窓保護絶縁構造
体15が本発明に従う変成処理で形成されている。このよ
うな構造を既述したＭＳＭ型受光素子に適用した場合、
検出対象の光の波長以下の幅寸法を有する光学窓保護絶
縁構造体15が複数個ある分、検出感度を上げることがで
きる。もちろん、光学窓保護絶縁構造体15の数（ひいて
はその下の光学窓の数）は任意である。FIG. 5 shows another application example of the present invention.
For explanation, the optically non-transmissive conductive thin film 12 has two or more optical window protective insulating structures 15 formed by a transformation process according to the present invention, although only two are shown in the figure. When such a structure is applied to the above-described MSM light receiving element,
Since there are a plurality of optical window protective insulating structures 15 having a width dimension equal to or smaller than the wavelength of light to be detected, detection sensitivity can be increased. Of course, the number of the optical window protection insulating structures 15 (and, consequently, the number of optical windows thereunder) is arbitrary.
【００３０】以上、本発明の幾つかの実施例に即し説明
したが、本発明の要旨構成に即する限り、当業者にとっ
て任意の改変は自由である。Although the present invention has been described with reference to several embodiments, any modifications can be freely made by those skilled in the art as long as they conform to the gist of the present invention.
【００３１】[0031]
【発明の効果】本発明によると、受光または発光を司る
光電変換機能部の一表面上の一部の所定面積領域が入射
光を受けるか発光を出力する所定幅の光学窓となってお
り、その両側に光非透過導電性薄膜が形成される必要の
ある光素子を製造するに際し、当該光学窓の領域確定と
光学窓の保護のための保護絶縁構造体の形成とが単一の
素工程で行なうことができ、極めて合理的である。保護
膜全面形成のための高価な高真空蒸着装置も不要にな
る。また、本発明の走査プローブ加工装置を用いる態様
においては、要すれば検出対象の光の波長以下の幅寸法
の光学窓とその保護絶縁のための高耐圧、高品位な構造
体が同一素工程で形成し得るので、高電界印加による光
励起キャリアの高速な引き抜きが可能となり、励起キャ
リアの再結合の影響も低減するため、高速かつ高感度な
受光素子を提供することができる。According to the present invention, a part of a predetermined area on one surface of a photoelectric conversion function part for receiving or emitting light is an optical window having a predetermined width for receiving incident light or outputting light. In manufacturing an optical element in which a light non-transmissive conductive thin film needs to be formed on both sides thereof, defining the area of the optical window and forming a protective insulating structure for protecting the optical window are a single elementary process. It is very reasonable. An expensive high vacuum deposition apparatus for forming the entire protective film is not required. Further, in the aspect using the scanning probe processing apparatus of the present invention, if necessary, an optical window having a width dimension equal to or smaller than the wavelength of light to be detected and a high withstand voltage, high quality structure for protective insulation thereof are formed in the same elementary process. Therefore, photoexcited carriers can be extracted at high speed by applying a high electric field, and the effect of recombination of excited carriers can be reduced. Therefore, a high-speed and high-sensitivity light-receiving element can be provided.
【図１】本発明製造方法の基本的な一実施例の概略構成
図である。FIG. 1 is a schematic configuration diagram of a basic embodiment of a manufacturing method of the present invention.
【図２】本発明製造方法に従いＭＳＭ型受光素子を作製
する場合の工程群に関する説明図である。FIG. 2 is an explanatory diagram relating to a process group in the case of manufacturing an MSM light receiving element according to the manufacturing method of the present invention.
【図３】図２の工程群によって試作された受光素子の測
定システムの説明図である。FIG. 3 is an explanatory diagram of a measuring system of a light receiving element prototyped by the process group of FIG. 2;
【図４】試作された本発明受光素子を測定した結果の説
明図である。FIG. 4 is an explanatory diagram of a result of measuring a prototype light-receiving element of the present invention.
【図５】本発明により作製される他の光素子の概略構成
図である。FIG. 5 is a schematic configuration diagram of another optical element manufactured according to the present invention.
【図６】従来における光素子の概略構成図である。FIG. 6 is a schematic configuration diagram of a conventional optical element.
10 本発明に従って作製された光素子， 11 光電変換機能部（光吸収部材）， 12 光非透過導電性薄膜（電圧印加部材）， 13 光学窓， 15 光学窓保護絶縁構造体（光ガイド部材）． 10 Optical element manufactured according to the present invention, 11 Photoelectric conversion function part (light absorbing member), 12 Non-light-transmitting conductive thin film (voltage applying member), 13 Optical window, 15 Optical window protective insulating structure (Light guide member) .
───────────────────────────────────────────────────── フロントページの続き (72)発明者 中川 格 茨城県つくば市梅園１丁目１番４ 工業 技術院電子技術総合研究所内 (72)発明者 杉山 佳延 茨城県つくば市梅園１丁目１番４ 工業 技術院電子技術総合研究所内 (56)参考文献 特開 平６−302843（ＪＰ，Ａ) 特開 平４−171405（ＪＰ，Ａ) 特開 昭61−183609（ＪＰ，Ａ) 特開 昭62−232602（ＪＰ，Ａ) ──────────────────────────────────────────────────続 き Continuing from the front page (72) Inventor Tadashi Nakagawa 1-1-4 Umezono, Tsukuba, Ibaraki Pref. Within the Research Institute of Electronics and Technology (72) Yoshinobu Sugiyama 1-1-4 Umezono, Tsukuba, Ibaraki (56) References JP-A-6-302284 (JP, A) JP-A-4-171405 (JP, A) JP-A-61-183609 (JP, A) JP-A 62 −232602 (JP, A)
Claims (8)
一表面上に光非透過導電性薄膜を形成する工程と；該光
非透過導電性薄膜の一部の領域を変成することにより、
所定の幅と長さを有する光透過性の光学窓保護絶縁構造
体を形成すると同時に、該形成される光学窓保護絶縁構
造体の下の上記光電変換機能部の表面における光学窓の
領域確定も行なう工程と；を含んで成る光素子の製造方
法。A step of forming a light non-transmissive conductive thin film on one surface of a photoelectric conversion function part which controls light emission or light reception; and denaturing a partial region of the light non-transmissive conductive thin film,
At the same time as forming the light-transmitting optical window protective insulating structure having a predetermined width and length, the area of the optical window on the surface of the photoelectric conversion function portion below the formed optical window protective insulating structure is also determined. Performing an optical device.
光非透過導電性薄膜は金属または合金であること；を特
徴とする光素子の製造方法。2. The method according to claim 1, wherein said non-light-transmitting conductive thin film is made of a metal or an alloy.
光非透過導電性薄膜は半導体であること；を特徴とする
光素子の製造方法。3. The method according to claim 1, wherein the non-light-transmitting conductive thin film is a semiconductor.
光非透過導電性薄膜は内部に半導体超格子構造を含むこ
と；を特徴とする光素子の製造方法。4. The method according to claim 1, wherein the light-impermeable conductive thin film includes a semiconductor superlattice structure therein.
法であって；上記変成は酸化であること；を特徴とする
光素子の製造方法。5. The method of manufacturing an optical device according to claim 1, wherein the modification is oxidation.
酸化は走査プローブ加工装置によりなされること；を特
徴とする光素子の製造方法。6. The manufacturing method according to claim 5, wherein said oxidation is performed by a scanning probe processing apparatus.
光非透過導電性薄膜において上記変成される上記一部の
領域は、該光非透過導電性薄膜にあって互いに離間した
複数個所にあること；を特徴とする光素子の製造方法。7. The manufacturing method according to claim 6, wherein the part of the modified region in the light-impermeable conductive thin film is located at a plurality of positions separated from each other in the light-impermeable conductive thin film. A method for manufacturing an optical element.
記載の製造方法であって；上記光電変換機能部は受光機
能を司る光吸収部材であり；上記変成されなかった上記
光非透過導電性薄膜部分は、上記光吸収部材に対し電圧
を印加する電圧印加部材として機能し；上記光学窓保護
絶縁構造体は該光吸収部材に光を導入する光ガイド部材
として機能すること；を特徴とする光素子の製造方法。8. The method of claim 1, 2, 3, 4, 5, 6, or 7.
The method according to claim 1, wherein the photoelectric conversion function part is a light absorbing member that performs a light receiving function; and the light non-transmissive conductive thin film portion that is not modified is a voltage that applies a voltage to the light absorbing member. A method for producing an optical element, wherein the optical window protective insulating structure functions as a light guide member for introducing light into the light absorbing member.
Priority Applications (8)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP808295A JP2666888B2 (en) | 1995-01-23 | 1995-01-23 | Optical device manufacturing method |
| EP99200499A EP0926742B1 (en) | 1995-01-23 | 1996-01-22 | Method of fabricating a photo-receiving device |
| EP96300405A EP0723302B1 (en) | 1995-01-23 | 1996-01-22 | Photo-receiving device |
| DE69614583T DE69614583T2 (en) | 1995-01-23 | 1996-01-22 | Light-sensitive device |
| DE69636016T DE69636016T2 (en) | 1995-01-23 | 1996-01-22 | Verharen to produce a light receiving device |
| US08/590,345 US5661328A (en) | 1995-01-23 | 1996-01-23 | Photo-receiving device, and method of fabricating a photo-device |
| US08/863,632 US5895227A (en) | 1995-01-23 | 1997-05-27 | Method of fabricating a photo-device |
| US08/900,826 US5945720A (en) | 1995-01-23 | 1997-07-25 | Photo-receiving device with light guide |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP808295A JP2666888B2 (en) | 1995-01-23 | 1995-01-23 | Optical device manufacturing method |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPH08204225A JPH08204225A (en) | 1996-08-09 |
| JP2666888B2 true JP2666888B2 (en) | 1997-10-22 |
Family
ID=11683420
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP808295A Expired - Lifetime JP2666888B2 (en) | 1995-01-23 | 1995-01-23 | Optical device manufacturing method |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JP2666888B2 (en) |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2007105593A1 (en) | 2006-03-13 | 2007-09-20 | Nec Corporation | Photodiode, method for manufacturing such photodiode, optical communication device and optical interconnection module |
| WO2008075542A1 (en) | 2006-12-20 | 2008-06-26 | Nec Corporation | Photodiode, optical communication device, and optical interconnection module |
Families Citing this family (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| KR100853067B1 (en) | 2004-04-05 | 2008-08-19 | 닛본 덴끼 가부시끼가이샤 | Photodiode and method for manufacturing same |
| JPWO2008136479A1 (en) | 2007-05-01 | 2010-07-29 | 日本電気株式会社 | Waveguide-coupled photodiode |
| US8269303B2 (en) | 2008-03-07 | 2012-09-18 | Nec Corporation | SiGe photodiode |
-
1995
- 1995-01-23 JP JP808295A patent/JP2666888B2/en not_active Expired - Lifetime
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2007105593A1 (en) | 2006-03-13 | 2007-09-20 | Nec Corporation | Photodiode, method for manufacturing such photodiode, optical communication device and optical interconnection module |
| US7800193B2 (en) | 2006-03-13 | 2010-09-21 | Nec Corporation | Photodiode, method for manufacturing such photodiode, optical communication device and optical interconnection module |
| WO2008075542A1 (en) | 2006-12-20 | 2008-06-26 | Nec Corporation | Photodiode, optical communication device, and optical interconnection module |
Also Published As
| Publication number | Publication date |
|---|---|
| JPH08204225A (en) | 1996-08-09 |
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