JPH0766978B2 - Photoelectric conversion element and manufacturing method - Google Patents
Photoelectric conversion element and manufacturing methodInfo
- Publication number
- JPH0766978B2 JPH0766978B2 JP1040226A JP4022689A JPH0766978B2 JP H0766978 B2 JPH0766978 B2 JP H0766978B2 JP 1040226 A JP1040226 A JP 1040226A JP 4022689 A JP4022689 A JP 4022689A JP H0766978 B2 JPH0766978 B2 JP H0766978B2
- Authority
- JP
- Japan
- Prior art keywords
- photoelectric conversion
- conversion element
- groove
- angle
- back surface
- 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 - Fee Related
Links
Classifications
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
- Y02E10/00—Energy generation through renewable energy sources
- Y02E10/50—Photovoltaic [PV] energy
- Y02E10/547—Monocrystalline silicon PV cells
Description
【発明の詳細な説明】 〔産業上の利用分野〕 本発明は光電変換素子、特に薄型化した光電変換素子の
光吸収効率の向上に関する。DETAILED DESCRIPTION OF THE INVENTION [Industrial field of application] The present invention relates to improvement of light absorption efficiency of a photoelectric conversion element, particularly a thinned photoelectric conversion element.
従来の光電変換素子は、ソーラ・セルズ（Solar Cell
s）、17（1986）p.75〜83に示されているように、光電
変換素子の表面または裏面に形成された、上記素子の厚
みに較べて比較的凹凸が小さいＶ字形溝構造などの表面
凹凸及び表面または裏面に形成された電極などの構造物
を除いて、ほぼ平板上の断面形状をしている。The conventional photoelectric conversion element is the Solar Cell
s), 17 (1986) p.75-83, a V-shaped groove structure formed on the front surface or the back surface of the photoelectric conversion element having relatively small unevenness as compared with the thickness of the element. Except for the surface irregularities and structures such as electrodes formed on the front or back surface, the cross-sectional shape is almost flat.
上記従来技術では、光電変換作用を行う基板の厚みが数
百μｍ以上ないと機械的に脆弱になり、素子を数cm〜数
十cmに大きくする事が困難である。そこで、基板を波板
状に加工することにより、光電変換作用を行う基板の実
質的な厚みを数十μｍ程度に小さくする事を考えた。し
かし、基板の厚みが小さくなると入射光を十分に吸収で
きなくなってしまう。In the above-mentioned conventional technology, if the thickness of the substrate for photoelectric conversion is several hundreds of μm or more, it becomes mechanically fragile, and it is difficult to increase the size of the device to several cm to several tens of cm. Therefore, it is considered that by processing the substrate into a corrugated plate, the substantial thickness of the substrate that performs photoelectric conversion is reduced to about several tens of μm. However, when the thickness of the substrate becomes small, it becomes impossible to sufficiently absorb the incident light.
本発明の目的は、上記光電変換素子の厚みを小さくて
も、入射光を十分に吸収する構造を提供する事にある。An object of the present invention is to provide a structure that sufficiently absorbs incident light even if the thickness of the photoelectric conversion element is small.
上記目的は、上記光電変換素子の表面に設けたＶ溝に整
合するように裏面に凸条を設け、上記Ｖ溝の角度を上記
凸条の凸部の角度より大きくすることにより達成され
る。The above object is achieved by providing a convex strip on the back surface so as to match the V groove provided on the front surface of the photoelectric conversion element, and making the angle of the V groove larger than the angle of the convex portion of the convex strip.
図面を用いて上記手段を説明する。 The above means will be described with reference to the drawings.
第２図に表面に設けたＶ溝とこれに整合して裏面に凸条
を設け、実質的な素子の厚みを薄くした構造を持つ光電
変換素子の構造を示す。この構造では、表側のＶ溝角度
（θ１）は裏側の凸条の凸部角度（θ１）と同じになっ
ている。これにより上記光電変換素子１にマクロ的な厚
みａに対して実質的な素子の厚みｂを小さくすることが
出来る。その一部を拡大して、第３図に示す。入射光２
は光電変換素子１に対し、特性の角度（θ３＝54.7°）
で表面３に入射し裏面内部４で反射され、表面３から再
び外部へ放射される。この場合、実質的な素子の厚みは
数十μｍ以下となるため、光電変換素子の基板の光の吸
収係数が小さい場合は、入射光２の一部が外部に透過し
てしまう。これは上記素子の出力電流の低下を招く。従
来は、裏面反射鏡５を形成し、基板からの透過光を正反
射することにより光路長を長くし光の吸収を増加せせて
おり、光閉じ込め率は約90％であった。FIG. 2 shows the structure of a V-shaped groove provided on the front surface and a photoelectric conversion element having a structure in which a convex stripe is provided on the back surface so as to match the V-shaped groove and the thickness of the element is substantially reduced. In this structure, the V-groove angle (θ 1 ) on the front side is the same as the convex portion angle (θ 1 ) of the convex strip on the back side. As a result, the substantial element thickness b of the photoelectric conversion element 1 can be made smaller than the macroscopic thickness a. A part of it is enlarged and shown in FIG. Incident light 2
Is the characteristic angle (θ 3 = 54.7 °) with respect to the photoelectric conversion element 1.
Is incident on the front surface 3, is reflected by the inner surface 4 of the back surface, and is emitted again from the front surface 3 to the outside. In this case, since the substantial thickness of the element is several tens of μm or less, if the light absorption coefficient of the substrate of the photoelectric conversion element is small, part of the incident light 2 will be transmitted to the outside. This causes a decrease in the output current of the device. Conventionally, the back reflection mirror 5 is formed and the light transmitted from the substrate is specularly reflected to increase the optical path length and increase the light absorption, and the light confinement ratio was about 90%.
これに対し本発明では、第１図に示す様に光電変換素子
11の光入射側の表面31のＶ溝角度（θ１）と裏面41に上
記Ｖ溝と整合して設けられた凸条の凸部角度（θ２）と
が異なり、（θ１＞θ２）に構成する。より詳細には第
４図と第５図を用いて説明する。第４図はＶ溝を構成し
ている半導体基板の一部拡大図、第５図は複数の半導体
片を考慮して光電変換素子を部分的に示した断面図であ
る。入射光21は前述の光電変換素子11の表面31に対し5
4.7°の角度で入射する。この場合、表面31と裏面41は
ある角度（θ）だけ傾いている。これにより、素子内を
通過した光は裏面41で反射され、素子内の表面31で内部
に反射される。特にこの角度（θ）を３°以上に設定す
れば、１回目に裏面41に到達した光は全反射される。も
し、裏面41に鏡に存在すれば、θを1.5°以上に設定す
ると素子内の表面31で全反射される。このようにθ１と
θ２を変え、特にθ１＞θ２とすることにより、一度入
射した光は基板11内に閉じ込められて効率よく吸収され
る。第５図はこの状態を示したものである。On the other hand, in the present invention, as shown in FIG.
The angle V of the V groove (θ 1 ) on the surface 31 on the light incident side of 11 is different from the angle (θ 2 ) of the convex portion of the ridge provided on the back surface 41 so as to be aligned with the above V groove (θ 1 > θ 2 ). The details will be described with reference to FIGS. 4 and 5. FIG. 4 is a partially enlarged view of a semiconductor substrate forming a V groove, and FIG. 5 is a sectional view partially showing a photoelectric conversion element in consideration of a plurality of semiconductor pieces. Incident light 21 is incident on surface 31 of photoelectric conversion element 11
It is incident at an angle of 4.7 °. In this case, the front surface 31 and the back surface 41 are inclined by a certain angle (θ). As a result, the light passing through the inside of the element is reflected by the back surface 41 and is reflected inside by the front surface 31 in the element. In particular, if this angle (θ) is set to 3 ° or more, the light that reaches the back surface 41 for the first time is totally reflected. If the mirror exists on the back surface 41, if θ is set to 1.5 ° or more, the light will be totally reflected on the surface 31 in the element. By changing θ 1 and θ 2 in this way, and particularly by setting θ 1 > θ 2 , the light that has once entered is confined in the substrate 11 and efficiently absorbed. FIG. 5 shows this state.
第６図を用いて本発明の実施例を説明する。基板66には
250μｍ厚のSi単結晶（100）を用い、まず光電変換素子
表面のＶ溝構造（角度74°）を機械加工で作製した。こ
の機械加工では、必要な刃の角度を有するダイシングソ
ーを用いた。上記Ｖ溝のピッチは240μｍである。この
表面のＶ溝構造に整合した形で、光電変換素子の裏面に
熱酸化膜をマスクにKOH溶液により異方性化学エッチン
グを裏面から行い裏面に凸条を形成する。上記表面Ｖ溝
に対応する裏面凸条の凸部の角度は70.5°である。An embodiment of the present invention will be described with reference to FIG. On board 66
Using a Si single crystal (100) having a thickness of 250 μm, a V-groove structure (angle 74 °) on the surface of the photoelectric conversion element was first produced by machining. This machining used a dicing saw with the required blade angle. The pitch of the V groove is 240 μm. Anisotropic chemical etching is performed on the back surface of the photoelectric conversion element using a KOH solution as a mask so as to match the V-groove structure on the front surface to form a convex stripe on the back surface. The angle of the convex portion of the rear convex strip corresponding to the front surface V groove is 70.5 °.
裏面凸条の凸部には、p+層67をAlの合金化処理により形
成した。表面には、加工歪層を除去したのちn+層65を燐
拡散により形成し、その表面をパッシベーション酸化膜
64で覆い、更にその上に光反射防止膜63を形成した。表
面Ｖ溝の凸部には表面電極61を形成し、酸化膜64に開け
たコンタクトホール62を通してn+層とオーミックコンタ
クトをとっている。裏面にはAgを真空蒸着して裏面電極
をかねた反射鏡68を形成した。これにより、表面から入
射した光は裏面で反射され、再び表面に到達してもその
ほとんどが全反射され、基板66の中に入射光のほぼ98％
が閉じこめられる。A p + layer 67 was formed on the convex portion of the rear convex stripe by an alloying treatment of Al. After removing the processing strained layer, an n + layer 65 is formed by phosphorus diffusion on the surface, and the surface is passivated oxide film.
It was covered with 64, and a light reflection preventing film 63 was further formed thereon. A surface electrode 61 is formed on the convex portion of the surface V groove, and an ohmic contact is made with the n + layer through a contact hole 62 formed in the oxide film 64. On the back surface, Ag was vacuum-deposited to form a reflecting mirror 68 also serving as a back surface electrode. As a result, the light incident from the front surface is reflected on the back surface, and most of the light is totally reflected even when it reaches the front surface again, and almost 98% of the incident light enters the substrate 66.
Is locked in.
上記説明では、表面のＶ溝構造を機械加工で作製した例
を示したが、裏面凸条の構造を機械加工で作製し、表面
のＶ溝構造を異方性化学エッチングで加工してもよい。
この場合裏面凸条の凸部の角度は約68°以下が好まし
い。In the above description, an example in which the V-groove structure on the front surface is manufactured by machining is shown, but the structure of the convex ridges on the back surface may be manufactured by machining and the V-groove structure on the front surface may be processed by anisotropic chemical etching. .
In this case, it is preferable that the angle of the convex portion of the rear surface ridge is about 68 ° or less.
なお、表面に設けた複数のＶ溝に整合して裏面に複数の
凸条を設けた構造の光電変換素子を機械的に補強するた
めに、第１図に示すように、上記表面がＶ溝で裏面が凸
条の構造を横切る方向に、裏面にＶ溝を設けた凸条42を
形成することができる。In order to mechanically reinforce the photoelectric conversion element having a structure in which a plurality of ridges are provided on the back surface in alignment with the plurality of V grooves provided on the front surface, as shown in FIG. Thus, it is possible to form the ridge 42 having the V groove on the back surface in the direction in which the back surface crosses the structure of the ridge.
また本発明をSi結晶を例に説明したが、他の結晶半導
体、例えばGaAs、InPのIII−Ｖ化合物半導体やCdS、CdT
e等のII−VI化合物等にも適用可能である。Although the present invention has been described by taking the Si crystal as an example, other crystal semiconductors such as GaAs and InP III-V compound semiconductors, CdS and CdT.
It is also applicable to II-VI compounds such as e.
上記説明から明らかなように、少なくとも一種類の半導
体からなり、その表面に形成した複数のＶ溝に整合して
裏面に複数の凸条を設け、実質的な素子の厚みを薄くし
た構造を持つ光電変換素子において、光入射側表面のＶ
溝角度が、該Ｖ溝に対応する裏面凸条の凸部の角度より
大きくなるように構成したことにより、入射光は表面お
よび裏面で全反射し、これにより入射光のほとんどを上
記基板内で吸収することができる。このような構造を持
つ上記光電変換素子に太陽光と同じスペクトルを持つ光
を照射したところ、入射光のほぼ100％を上記基板内で
吸収させることができた。As is clear from the above description, it has a structure in which at least one kind of semiconductor is formed, a plurality of convex stripes are provided on the back surface in alignment with a plurality of V grooves formed on the surface thereof, and the thickness of the element is substantially reduced. In the photoelectric conversion element, V on the light incident side surface
Since the groove angle is configured to be larger than the angle of the convex portion of the rear surface ridge corresponding to the V groove, the incident light is totally reflected on the front surface and the back surface, whereby most of the incident light is reflected in the substrate. Can be absorbed. When the photoelectric conversion element having such a structure was irradiated with light having the same spectrum as sunlight, almost 100% of incident light could be absorbed in the substrate.
【図面の簡単な説明】 第１図は本発明の一実施例を示す外観図、第２図は従来
の光電変換素子の外観図、第３図は従来の構造での入射
光の通過経路を示す局所部の断面図、第４図は本発明の
構造での入射光の通過経路を示す局所部の断面図、第５
図は本発明の構造での入射光の通過経路を示す断面図、
第６図は本発明の一実施例の断面を示す外観図。BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is an external view showing an embodiment of the present invention, FIG. 2 is an external view of a conventional photoelectric conversion element, and FIG. 3 is an incident light passage path in a conventional structure. FIG. 4 is a sectional view of the local portion shown in FIG. 4, and FIG. 4 is a sectional view of the local portion showing a passage path of incident light in the structure of the present invention.
The figure is a cross-sectional view showing the passage path of incident light in the structure of the present invention,
FIG. 6 is an external view showing a cross section of an embodiment of the present invention.
Claims (4)
表面に形成した複数のＶ溝に整合して裏面に複数の凸条
を設け、実質的な素子の厚みを薄くした構造を持つ光電
変換素子において、光入射側表面のＶ溝角度が、該Ｖ溝
に対応する裏面凸条の凸部の角度より大きくなるように
構成したことを特徴とする光電変換素子。1. A photoelectric conversion element which is made of at least one kind of semiconductor and has a structure in which a plurality of convex stripes are provided on the back surface in alignment with a plurality of V-grooves formed on the surface of the semiconductor and the thickness of the element is substantially reduced. In the photoelectric conversion element, the angle of the V groove on the surface on the light incident side is larger than the angle of the convex portion of the rear surface ridge corresponding to the V groove.
において、光入射側の上記表面Ｖ溝角度が上記裏面凸条
の凸部の角度より1.5°以上大きくなるように構成した
ことを特徴とする光電変換素子。2. The photoelectric conversion device according to claim 1, wherein the angle of the front surface V groove on the light incident side is larger than the angle of the convex portion of the rear surface convex stripe by 1.5 ° or more. Characteristic photoelectric conversion element.
光電変換素子において、上記表面がＶ溝で裏面が凸条の
構造を横切る方向に形成され、裏面にＶ溝を設けた凸条
を素子表面に有していることを特徴とする光電変換素
子。3. The photoelectric conversion device according to claim 1 or 2, wherein the front surface is formed in a direction crossing the V groove and the back surface is formed in a direction crossing the convex stripe structure, and the V groove is formed on the back surface. A photoelectric conversion element having stripes on the element surface.
かに記載の光電変換素子において、上記Ｖ溝または凸条
の構造を、少なくとも異方性化学エッチングおよび機械
加工のいずれかを用いて形成することを特徴とする光電
変換素子の製造方法。4. The photoelectric conversion element according to any one of claims 1 to 3, wherein the structure of the V groove or the convex stripe is formed by at least one of anisotropic chemical etching and machining. A method for manufacturing a photoelectric conversion element, which is characterized by being formed using the same.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP1040226A JPH0766978B2 (en) | 1989-02-22 | 1989-02-22 | Photoelectric conversion element and manufacturing method |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP1040226A JPH0766978B2 (en) | 1989-02-22 | 1989-02-22 | Photoelectric conversion element and manufacturing method |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPH02220479A JPH02220479A (en) | 1990-09-03 |
| JPH0766978B2 true JPH0766978B2 (en) | 1995-07-19 |
Family
ID=12574837
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP1040226A Expired - Fee Related JPH0766978B2 (en) | 1989-02-22 | 1989-02-22 | Photoelectric conversion element and manufacturing method |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPH0766978B2 (en) |
Families Citing this family (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH0793450B2 (en) * | 1990-09-19 | 1995-10-09 | 株式会社日立製作所 | Corrugated solar cell |
| JP5427531B2 (en) * | 2009-09-29 | 2014-02-26 | 三菱重工業株式会社 | Photodetection element, photodetection device, infrared detection element, infrared detection device |
Family Cites Families (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS56137686A (en) * | 1980-03-31 | 1981-10-27 | Shunpei Yamazaki | Mis-type photoelectric transducing device |
| JPS58159761U (en) * | 1982-04-20 | 1983-10-25 | シャープ株式会社 | solar cells |
-
1989
- 1989-02-22 JP JP1040226A patent/JPH0766978B2/en not_active Expired - Fee Related
Also Published As
| Publication number | Publication date |
|---|---|
| JPH02220479A (en) | 1990-09-03 |
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