JP2004363572A

JP2004363572A - Semiconductor light emitting device and light emitting diode

Info

Publication number: JP2004363572A
Application number: JP2004141779A
Authority: JP
Inventors: Toshiki Yoshiuji; 俊揮吉氏; Ryoichi Takeuchi; 良一竹内
Original assignee: Showa Denko KK
Current assignee: Resonac Holdings Corp
Priority date: 2003-05-12
Filing date: 2004-05-12
Publication date: 2004-12-24

Abstract

<P>PROBLEM TO BE SOLVED: To improve luminance and uniformity of intensity of light emission in a surface of a light emitting device, especially around the center of the surface even if the light emitting device is large. <P>SOLUTION: The semiconductor light emitting device of this invention comprises a semiconductor substrate 11 which has a first electrode 15 on the back face, a semiconductor layer 13 accompanied by a light emitting part 12 formed on the substrate 11, a distributed electrode 17 which is distributed on a part of the surface of the semiconductor layer 13 and in ohmic contact with the layer 13, a transparent conductive film 14 which covers the surface of the semiconductor layer 13 and the distributed electrode 17 and is connected to the distributed electrode 17, a pedestal electrode 16 which is formed on a part of the surface of the transparent conductive film 14 and connected to it. One side of the light emitting surface of the semiconductor layer 13 is more than 0.8mm in size and a plurality of pedestal electrodes 16 are arranged on the transparent conductive film 14 in a region within 0.3mm from the periphery of the film 14. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

この発明は、半導体層の表面から光を取り出す半導体発光素子および発光ダイオードに関する。 The present invention relates to a semiconductor light emitting device and a light emitting diode that extract light from a surface of a semiconductor layer.

従来、光を取り出す表面（発光面）の面積が０．２５ｍｍ²以上の大型の半導体発光素子として、発光面の一辺が０．５ｍｍ以上で、１つの台座電極とワイヤボンドによる配線が１本であるものが知られている（例えば、特許文献１参照）。
特開２００２−４３６２１号公報 Conventionally, as a large-sized semiconductor light emitting element having a light extraction surface (light emitting surface) area of 0.25 mm ² or more, one side of the light emitting surface is 0.5 mm or more, and one pedestal electrode and one wire by wire bonding are used. Some are known (for example, see Patent Document 1).
JP-A-2002-43621

上記の特許文献１の図１，図２に示された大型発光素子は、裏面に第１の電極１５が形成された半導体基板１１と、この半導体基板１１上に形成された、発光部１２を含む半導体層１３と、半導体層１３の表面の一部に分配して形成されその半導体層１３とオーミック接触をなす分配電極１７と、半導体層１３の表面と分配電極１７とを覆って形成され分配電極１７と導通する透明導電膜１４と、透明導電膜１４の表面の一部に形成され透明導電膜１４と導通する台座電極１６とを有しており、この構成によって、電極と半導体層との良好なオーミック接触を実現し、かつ半導体発光素子の駆動電流を発光層（半導体層）の全面に広げて半導体層の表面の全面から発光を得ることができるようにしている。 The large-sized light-emitting element shown in FIGS. 1 and 2 of Patent Document 1 includes a semiconductor substrate 11 having a first electrode 15 formed on the back surface, and a light-emitting portion 12 formed on the semiconductor substrate 11. A semiconductor layer 13 including the semiconductor layer 13, a distribution electrode 17 formed on a part of the surface of the semiconductor layer 13 and forming an ohmic contact with the semiconductor layer 13, and a distribution electrode formed on the surface of the semiconductor layer 13 and the distribution electrode 17. It has a transparent conductive film 14 that conducts with the electrode 17 and a pedestal electrode 16 that is formed on a part of the surface of the transparent conductive film 14 and conducts with the transparent conductive film 14. Good ohmic contact is realized, and the driving current of the semiconductor light emitting element is spread over the entire surface of the light emitting layer (semiconductor layer) so that light emission can be obtained from the entire surface of the semiconductor layer.

しかし、上記の大型発光素子では、１つの台座電極を周辺部に配置することで、素子中央付近の発光強度を大幅に改善できるものの、台座電極からの距離に従い発光強度が低下するという問題点があった。 However, in the above-described large-sized light-emitting element, by disposing one pedestal electrode in the peripheral portion, the luminous intensity near the center of the element can be greatly improved, but the luminous intensity decreases with the distance from the pedestal electrode. there were.

本発明は、上記の問題点に鑑み提案されたもので、発光素子が大型であっても、発光強度の面内均一性、特に中央付近の均一性を改善することができ、輝度を向上させることができる半導体発光素子および発光ダイオードを提供することを目的とする。 The present invention has been proposed in view of the above problems, and can improve the in-plane uniformity of the emission intensity, particularly the uniformity near the center, and improve the luminance, even when the light emitting element is large. It is an object of the present invention to provide a semiconductor light-emitting device and a light-emitting diode that can be used.

１）上記目的を達成するために、第１の発明は、裏面に第１の電極が形成された半導体基板と、前記半導体基板上に形成された、発光部を含む半導体層と、前記半導体層の表面の一部に分配して形成されその半導体層とオーミック接触をなす分配電極と、前記半導体層の表面と前記分配電極とを覆って形成されその分配電極と導通する透明導電膜と、前記透明導電膜の表面の一部に形成されその透明導電膜と導通する台座電極とを有する半導体発光素子において、前記半導体層の光を取り出す表面（発光面）の１辺が０．８ｍｍ以上であり、台座電極は、透明導電膜の外周から０．３ｍｍ以内の領域に複数配置されている、ことを特徴としている。 1) In order to achieve the above object, a first invention is directed to a semiconductor substrate having a first electrode formed on a back surface, a semiconductor layer including a light emitting portion formed on the semiconductor substrate, and the semiconductor layer A distribution electrode that is formed to be distributed over part of the surface of the semiconductor layer and makes ohmic contact with the semiconductor layer, a transparent conductive film that is formed to cover the surface of the semiconductor layer and the distribution electrode, and that is electrically connected to the distribution electrode; In a semiconductor light emitting device having a pedestal electrode formed on a part of the surface of a transparent conductive film and conducting with the transparent conductive film, one side of a surface (light emitting surface) of the semiconductor layer from which light is extracted is 0.8 mm or more. A plurality of pedestal electrodes are arranged in a region within 0.3 mm from the outer periphery of the transparent conductive film.

２）第２の発明は、上記した１）項に記載の発明の構成に加えて、前記発光面のうち発光を妨げる領域が素子上面表面積に対して３０％以下である、ことを特徴としている。 2) The second invention is characterized in that, in addition to the constitution of the invention described in the above item 1), a region of the light-emitting surface which prevents light emission is 30% or less of a surface area of an element upper surface. .

３）第３の発明は、上記した１）項または２）項に記載の発明の構成に加えて、前記分配電極は、線幅が０．０３０ｍｍ以下の線状電極を格子状に形成してなり、かつ金属で構成されて厚さが０．５０μｍ以下である、ことを特徴としている。 3) In the third invention, in addition to the configuration of the invention described in the above item 1) or 2), the distribution electrode is formed by forming a linear electrode having a line width of 0.030 mm or less in a lattice shape. And is made of metal and has a thickness of 0.50 μm or less.

４）第４の発明は、上記した１）項から３）項の何れか１項に記載の発明の構成に加えて、前記台座電極は、透明導電膜の表面の四隅に配置されている、ことを特徴としている。 4) In a fourth aspect of the present invention, in addition to the configuration of the invention described in any one of the above items 1) to 3), the pedestal electrodes are arranged at four corners of a surface of the transparent conductive film. It is characterized by:

５）第５の発明は、上記した１）項から４）項の何れか１項に記載の発明の構成に加えて、前記透明導電膜は酸化インジウム錫（ＩＴＯ）らなる、ことを特徴としている。 5) The fifth invention is characterized in that, in addition to the constitution of the invention described in any one of the above items 1) to 4), the transparent conductive film is made of indium tin oxide (ITO). I have.

６）第６の発明は、上記した１）項から５）項の何れか１項に記載の発明の構成に加えて、１アンペア印加時の順方向電圧が４．００Ｖ以下である、ことを特徴としている。 6) According to a sixth aspect of the invention, in addition to the configuration of the invention described in any one of the above items 1) to 5), the forward voltage at the time of applying 1 ampere is 4.00 V or less. Features.

７）第７の発明は、上記した１）項から６）項の何れか１項に記載の発明の構成に加えて、前記発光部はＡｌＧａＩｎＰからなる、ことを特徴としている。 7) A seventh invention is characterized in that, in addition to the configuration of the invention described in any one of the above items 1) to 6), the light emitting section is made of AlGaInP.

８）第８の発明は、上記した１）項から７）項の何れか１項に記載の発明の構成に加えて、前記発光部はＭＯＣＶＤ法により形成されている、ことを特徴としている。 8) An eighth invention is characterized in that, in addition to the structure of the invention described in any one of the above items 1) to 7), the light emitting section is formed by MOCVD.

９）第９の発明は、発光ダイオードであって、上記した１）項から８）項に記載の半導体発光素子を用いたことを特徴としている。 9) A ninth invention is a light-emitting diode, characterized by using the semiconductor light-emitting device described in the above items 1) to 8).

１０）第１０の発明は、発光ダイオードであって、上記した１）項から８）項に記載の半導体発光素子を用い、ワイヤボンドによる配線が複数であることを特徴としている。 10) A tenth aspect of the present invention is a light emitting diode, wherein the semiconductor light emitting device according to any one of the above items 1) to 8) is used, and a plurality of wirings are provided by wire bonding.

この発明の半導体発光素子および発光ダイオードでは、半導体層の表面の一部に分配電極を設け、その分配電極を透明導電膜で覆い、その透明導電膜の外周から０．３ｍｍ以内の領域に台座電極を複数配置するようにしたので、発光面の１辺が０．８ｍｍ以上となるような大型の半導体発光素子であっても、発光強度の面内均一性、特に中央付近の均一性を改善することができ、輝度を向上させることができる。 In the semiconductor light-emitting device and the light-emitting diode of the present invention, a distribution electrode is provided on a part of the surface of the semiconductor layer, the distribution electrode is covered with a transparent conductive film, and a pedestal electrode is formed in an area within 0.3 mm from the outer periphery of the transparent conductive film. Are arranged, so that even in the case of a large-sized semiconductor light emitting element in which one side of the light emitting surface is 0.8 mm or more, the in-plane uniformity of the light emitting intensity, particularly the uniformity near the center is improved. And the luminance can be improved.

以下にこの発明の実施の形態を詳細に説明する。 Hereinafter, embodiments of the present invention will be described in detail.

図１、図２および図３は本発明の半導体発光素子の概略構成を模式的に示す図で、図１はその平面図、図２は図１のＩ−Ｉ線断面を示す図、図３は図１のＩ’−Ｉ’線断面を示す図である。 1, 2 and 3 are diagrams schematically showing a schematic configuration of a semiconductor light emitting device of the present invention. FIG. 1 is a plan view thereof, FIG. 2 is a diagram showing a cross section taken along line II of FIG. FIG. 2 is a view showing a cross section taken along line I′-I ′ of FIG. 1.

本実施例で作製した半導体発光素子は、赤橙色の発光を行う発光ダイオード（ＬＥＤ）である。このＬＥＤでは、亜鉛（Ｚｎ）をドープしたｐ形の（００１）面を有するＧａＡｓ単結晶からなる半導体基板１１上に順次積層された、Ｚｎをドープしたｐ形のＧａＡｓからなる緩衝層１３１、Ｚｎをドープしたｐ形のＡｌＧａＡｓからなる光反射層１３２、Ｚｎをドープしたｐ形の（Ａｌ_0.7Ｇａ_0.3）_0.5Ｉｎ_0.5Ｐからなる下部クラッド層１３３、アンドープの（Ａｌ_0.2Ｇａ_0.8）_0.5Ｉｎ_0.5Ｐからなる発光層１３４、および珪素（Ｓｉ）をドープしたｎ形の（Ａｌ_0.7Ｇａ_0.3）_0.5Ｉｎ_0.5Ｐからなる上部クラッド層１３５から、半導体層１３が構成されている。また、このＬＥＤの発光部１２は、下部クラッド層１３３、発光層１３４、上部クラッド層１３５から構成されている。したがって、発光部１２はＡｌＧａＩｎＰからなる。 The semiconductor light emitting device manufactured in this embodiment is a light emitting diode (LED) that emits red-orange light. In this LED, a buffer layer 131 made of Zn-doped p-type GaAs, which is sequentially laminated on a semiconductor substrate 11 made of a GaAs single crystal having a p-type (001) plane doped with zinc (Zn), Zn Light reflecting layer 132 made of p-type AlGaAs doped with Zn, lower cladding layer 133 made of p-type (Al _0.7 Ga _0.3 ) _0.5 In _0.5 P doped with Zn, undoped (Al _0.2 Ga _0.8 ) _0.5 In _0.5 P The semiconductor layer 13 is composed of a light emitting layer 134 made of and an upper clad layer 135 made of n-type (Al _0.7 Ga _0.3 ) _0.5 In _0.5 P doped with silicon (Si). The light emitting section 12 of the LED includes a lower cladding layer 133, a light emitting layer 134, and an upper cladding layer 135. Therefore, the light emitting section 12 is made of AlGaInP.

以上のように構成された半導体ウェーハにおいて、半導体基板１の裏面に第１の電極１５として、金・亜鉛（Ａｕ・Ｚｎ）合金からなるｐ形オーミック電極を厚さが１μｍとなるように真空蒸着法により形成した。また、分配電極１７を形成するために、先ず膜厚を約５０ｎｍとするＡｕ９３重量％とＧｅ７重量％の合金からなる金・ゲルマニウム合金膜を、上部クラッド層１３５の表面の全面に、一般的な真空蒸着法により一旦被着させた。続けて、その金・ゲルマニウム合金膜の表面上に、膜厚を約５０ｎｍとする金（Ａｕ）膜を被着させた。次に、金・ゲルマニウム合金膜と金膜とからなる２層構造の重層膜が分配電極１７の形になるように、一般的なフォトリソグラフィー手段を利用してパターニングを施し、０．８ｍｍ□領域に線幅２０μｍとする格子状の分配電極１７を形成した。この金・ゲルマニウム合金膜と金膜とからなる２層構造の分配電極１７は、図１に示すように、素子周辺領域を除く上部クラッド層１３５の表面上に配置した。 In the semiconductor wafer configured as described above, a p-type ohmic electrode made of a gold-zinc (Au-Zn) alloy is vacuum-deposited on the back surface of the semiconductor substrate 1 as the first electrode 15 so as to have a thickness of 1 μm. It was formed by a method. In order to form the distribution electrode 17, first, a gold / germanium alloy film made of an alloy of 93% by weight of Au and 7% by weight of Ge having a thickness of about 50 nm is formed on the entire surface of the upper cladding layer 135 by a general method. It was once applied by a vacuum deposition method. Subsequently, a gold (Au) film having a thickness of about 50 nm was deposited on the surface of the gold-germanium alloy film. Next, patterning is performed using a general photolithography method so that a multilayer film having a two-layer structure composed of a gold-germanium alloy film and a gold film is formed in the shape of the distribution electrode 17, and a 0.8 mm square region is formed. Then, a grid-shaped distribution electrode 17 having a line width of 20 μm was formed. As shown in FIG. 1, the distribution electrode 17 having a two-layer structure composed of the gold / germanium alloy film and the gold film was disposed on the surface of the upper cladding layer 135 excluding the peripheral region of the element.

上記の分配電極１７の形成後、アルゴン（Ａｒ）気流中において５００℃で１５分間の合金化熱処理を施し、分配電極１７と上部クラッド層１３５とのオーミック接触を形成した。次に、上部クラッド層１３５とその表面の分配電極１７とを覆って、一般のマグネトロンスパッタリング法により、酸化インジウム錫（ＩＴＯ）からなる膜を透明導電膜１４として半導体層１３上に被着させた。透明導電膜１４の比抵抗は約２×１０^-4Ω・ｃｍであり、この実施例のＬＥＤの発光波長の光に対する透過率は、９４％であった。またこの透明導電膜１４の膜厚は約３００ｎｍとした。一般的なＸ線回折分析法により、透明導電膜１４は＜０００１＞方向（Ｃ軸）に優先的に配向した多結晶膜であることが分かった。 After the formation of the distribution electrode 17, an alloying heat treatment was performed at 500 ° C. for 15 minutes in an argon (Ar) stream to form ohmic contact between the distribution electrode 17 and the upper cladding layer 135. Next, a film made of indium tin oxide (ITO) was applied as a transparent conductive film 14 on the semiconductor layer 13 by a general magnetron sputtering method so as to cover the upper clad layer 135 and the distribution electrode 17 on the surface thereof. . The specific resistance of the transparent conductive film 14 was about 2 × 10 ⁻⁴ Ω · cm, and the transmittance of the LED of this example for light of the emission wavelength was 94%. The thickness of the transparent conductive film 14 was about 300 nm. General X-ray diffraction analysis revealed that the transparent conductive film 14 was a polycrystalline film preferentially oriented in the <0001> direction (C axis).

次に、透明導電膜１４の全面に、一般的なフォトレジスト材料を塗布した後、台座電極１６を設けるべき領域を、公知のフォトリソグラフィー技術を利用してパターニングした。その後、パターニングされたレジスト材料を残置させたままで、全面に金（Ａｕ）膜を真空蒸着法により被着させた。金（Ａｕ）膜の厚さは約１２００ｎｍとした。その後、レジスト材料を剥離するに併せて、周知のリフト−オフ手段により、台座電極１６の形成予定領域に限定して上記の金膜を残留させた。これにより、直径を約１１０μｍとする円形の金からなる台座電極１６を、透明導電膜１４の外周から０．３ｍｍ以内の領域であって、透明導電膜１４の四隅に形成した。 Next, after a general photoresist material was applied to the entire surface of the transparent conductive film 14, a region where the pedestal electrode 16 was to be provided was patterned using a known photolithography technique. Thereafter, a gold (Au) film was deposited on the entire surface by a vacuum deposition method while the patterned resist material was left. The thickness of the gold (Au) film was about 1200 nm. After that, along with the removal of the resist material, the above-mentioned gold film was left only in the region where the pedestal electrode 16 was to be formed by a well-known lift-off means. As a result, the pedestal electrodes 16 made of circular gold having a diameter of about 110 μm were formed in the four corners of the transparent conductive film 14 within a region within 0.3 mm from the outer periphery of the transparent conductive film 14.

上記のようにして第１の電極１５および分配電極１７、透明導電膜１４、台座電極１６を形成したエピタキシャルウェーハを、ダイサーにより素子の形状に裁断して個別に細分化し、ＬＥＤとなした。ＬＥＤは、図１に示すように平面的に見て一辺を１０００μｍとする正方形としたことより、半導体層１３の光を取り出す表面（発光面）の面積は約０．９ｍｍ²となった。さらに、図１に示す素子の４つの台座電極１６の各々に、金線でワイヤボンドを行い合計４本を第２の電極端子（台座電極）に接続した。 The epitaxial wafer on which the first electrode 15, the distribution electrode 17, the transparent conductive film 14, and the pedestal electrode 16 were formed as described above was cut into element shapes by a dicer and individually divided into LEDs. As shown in FIG. 1, the LED had a square shape with a side of 1000 μm when viewed in a plan view, so that the area of the surface (light emitting surface) of the semiconductor layer 13 from which light was extracted was about 0.9 mm ² . Further, each of the four pedestal electrodes 16 of the element shown in FIG. 1 was wire-bonded with a gold wire, and a total of four were connected to the second electrode terminal (pedestal electrode).

以上のように、本実施例により、作製したＬＥＤの第１の電極１５よりなる第１の電極端子と、台座電極１６よりなる第２の電極端子に順方向に電流を通流したところ、発光面から透明導電膜１４を介して、波長を約６２０ｎｍとする赤橙色の光が出射された。また、その発光スペクトルの半値幅は、分光器により測定した結果、約２０ｎｍであり、単色性に優れる発光が得られた。１アンペア（Ａ）の電流を通流した際の順方向電圧（Ｖｆ：１Ａ当り）は、各分配電極１７の良好なオーミック特性を反映し、約３．５ボルト（Ｖ）となった。さらに本実施例のＬＥＤのＸ−Ｘ線上の発光面内の発光強度分布を測定した結果を図１１に示す。オーミック性の分配電極１７を発光面に格子状に配置し、かつ透明導電膜１４の四隅に台座電極１６を設けた効果により、発光面の周縁の領域においても均一な発光が認められ、発光面の面積が０．５０ｍｍ²以上のＬＥＤであっても発光面内で均一な発光が得られているのが分る。また、本発明のＬＥＤの輝度は２０００ｍｃｄであった。発光強度および均一性の優れた発光装置がえられた。 As described above, according to the present example, when a current was passed in the forward direction to the first electrode terminal composed of the first electrode 15 and the second electrode terminal composed of the pedestal electrode 16 of the LED manufactured, light emission was observed. Red-orange light having a wavelength of about 620 nm was emitted from the surface through the transparent conductive film 14. The half-width of the emission spectrum was measured by a spectroscope and was found to be about 20 nm. Thus, emission having excellent monochromaticity was obtained. The forward voltage (Vf: per 1 A) when a current of 1 Amp (A) was passed was about 3.5 volts (V), reflecting the good ohmic characteristics of each distribution electrode 17. Further, FIG. 11 shows the result of measuring the light emission intensity distribution in the light emitting surface on the XX line of the LED of this example. Due to the effect of arranging the ohmic distribution electrodes 17 on the light emitting surface in a lattice pattern and providing the pedestal electrodes 16 at the four corners of the transparent conductive film 14, uniform light emission is recognized even in the peripheral region of the light emitting surface. It can be seen that uniform light emission was obtained within the light emitting surface even with an LED having an area of 0.50 mm ² or more. Further, the luminance of the LED of the present invention was 2000 mcd. A light emitting device having excellent light emission intensity and uniformity was obtained.

なお、本実施例ではｐ型の半導体基板を用いてＬＥＤを作製したが、ｎ型の半導体基板を用いて作製したＬＥＤでも本発明の効果が得られる。また、本発明のＬＥＤの発光部の材質にはＡｌＧａＩｎＰを用いたが、発光部の材料を変えても本発明の効果が得られる。特にＭＯＣＶＤ法で半導体層が積層されるような半導体層の厚さが薄い半導体発光素子、例えば発光部がＡｌＧａＩｎＰあるいはＡｌＧａＩｎＮ、ＡｌＧａＡｓ等からなる半導体発光素子においては、本発明の効果が特に大きい。また、実施例では、チップＬＥＤ形状のＬＥＤを示したが、形状の異なるいわゆる砲弾型等でも同様の効果が得られる。さらに分配電極は、本実施例の格子状以外に独立していない放射状、ドーナッツ状、螺旋状、額縁状、あるいは枝状の分配電極を半導体層１３の表面に均等に配置しても良い。また、分配電極の材料には、半導体層１３の最も表面側の層がｐ型の場合はＡｕＺｎ、ＡｕＢｅやＮｉ等を、また半導体層１３の最も表面側の層がｎ型の場合はＡｕＧｅ、Ｎｉ、ＡｕＳｉやＴｉ等を用いることができる。 In this embodiment, the LED is manufactured using the p-type semiconductor substrate. However, the effects of the present invention can be obtained with the LED manufactured using the n-type semiconductor substrate. Although the light emitting portion of the LED of the present invention is made of AlGaInP, the effect of the present invention can be obtained by changing the material of the light emitting portion. The effect of the present invention is particularly great in a semiconductor light emitting device having a thin semiconductor layer in which the semiconductor layers are stacked by the MOCVD method, for example, a semiconductor light emitting device in which the light emitting portion is made of AlGaInP, AlGaInN, AlGaAs, or the like. Further, in the embodiment, the LED of the chip LED shape is shown, but a similar effect can be obtained by a so-called shell type having a different shape. Further, as the distribution electrode, a radial, donut-shaped, spiral, frame-shaped, or branched distribution electrode which is not independent other than the lattice-shaped distribution electrode of the present embodiment may be uniformly arranged on the surface of the semiconductor layer 13. The material of the distribution electrode is AuZn, AuBe, Ni, or the like when the outermost layer of the semiconductor layer 13 is p-type, or AuGe when the outermost layer of the semiconductor layer 13 is n-type. Ni, AuSi, Ti, or the like can be used.

また、上記の説明では、分配電極１７の線幅を２０μｍとしたが、良好な発光特性を得るためにの最大幅として、線幅は３０μｍ以下であればよい。 Further, in the above description, the line width of the distribution electrode 17 is set to 20 μm. However, the line width may be 30 μm or less as the maximum width for obtaining good emission characteristics.

また、発光面のうち発光を妨げる領域は、上記の例では素子上面表面積に対して約２８％であるが、図６に示す素子タイプで３０％を超えると発光強度の低下が著しかったため、素子上面表面積に対して３０％以下とするのがよい。なお、ここで発光を妨げる領域とは、台座電極及び分配電極の占める領域をいう。 In the above example, the area of the light-emitting surface that hinders light emission is about 28% of the surface area of the element. However, when the area exceeds 30% in the element type shown in FIG. The upper surface area is preferably 30% or less. Here, the region that blocks light emission refers to a region occupied by the pedestal electrode and the distribution electrode.

さらに、ＬＥＤは、平面的に見て一辺を１０００μｍとする正方形としたことより、発光面の面積は約０．９ｍｍ²となったが、本発明は、発光面の１辺が０．８ｍｍ以上のものに適用するとき、発光強度の均一化等の本発明に特有な効果が得られる。 Further, the LED has a square shape with one side of 1000 μm when viewed in plan, so that the area of the light emitting surface is about 0.9 mm ^2. However, according to the present invention, one side of the light emitting surface is 0.8 mm or more. When applied to the present invention, effects unique to the present invention, such as uniform light emission intensity, can be obtained.

以上述べたように、この発明の半導体発光素子および発光ダイオードでは、半導体層１３の表面の一部に分配電極１７を設け、その分配電極１７を透明導電膜１４で覆い、その透明導電膜１４の外周から０．３ｍｍ以内の領域に台座電極１６を複数配置するようにしたので、発光面の１辺が０．８ｍｍ以上となるような大型の半導体発光素子であっても、発光強度の面内均一性、特に中央付近の均一性を改善することができ、輝度を向上させることができる。 As described above, in the semiconductor light emitting device and the light emitting diode of the present invention, the distribution electrode 17 is provided on a part of the surface of the semiconductor layer 13, the distribution electrode 17 is covered with the transparent conductive film 14, Since a plurality of pedestal electrodes 16 are arranged in a region within 0.3 mm from the outer periphery, even in the case of a large-sized semiconductor light-emitting element in which one side of the light-emitting surface is 0.8 mm or more, the luminous intensity is within the plane. Uniformity, particularly near the center, can be improved, and luminance can be improved.

また、透明導電膜１４により分配電極１７への電気伝導を確保しているので、台座電極１６と分配電極１７との間にワイヤボンドによる配線を行う必要がなく、組み立てコストを低減することができる。また分配電極１７の面積を小さくすることができ、分配電極１７で発光の取出しが妨害されることを防止して、発光効率を良好なものとすることができる。 Further, since electric conduction to the distribution electrode 17 is ensured by the transparent conductive film 14, there is no need to perform wiring by wire bonding between the pedestal electrode 16 and the distribution electrode 17, and the assembly cost can be reduced. . In addition, the area of the distribution electrode 17 can be reduced, and the emission of light can be prevented from being obstructed by the distribution electrode 17, so that the luminous efficiency can be improved.

（比較例１）比較例１では、上記の実施例と同じ構造の半導体層を形成したエピタキシャルウェーハを用いて、発光面積がほぼ同じ大きさの半導体発光素子を作製した。比較例１で作製した半導体発光素子を図４、図５に示す。 Comparative Example 1 In Comparative Example 1, a semiconductor light emitting device having a light emitting area of almost the same size was manufactured using an epitaxial wafer on which a semiconductor layer having the same structure as that of the above-described example was formed. FIGS. 4 and 5 show the semiconductor light emitting device manufactured in Comparative Example 1. FIG.

図４は比較例１で作製した半導体発光素子の平面図、図５は図４のＩ−Ｉ線に沿った断面図である。図４、図５で符号２１，２２，２３，２５，２３１，２３２，２３３，２３４，２３５で示した部分は、図１、図２、図３の符号１１，１２，１３，１５，１３１，１３２，１３３，１３４，１３５で示した部分とそれぞれ対応する。 FIG. 4 is a plan view of the semiconductor light emitting device manufactured in Comparative Example 1, and FIG. 5 is a cross-sectional view taken along the line II of FIG. 4 and 5, the parts indicated by reference numerals 21, 22, 23, 25, 231, 232, 233, 234, and 235 correspond to the reference numerals 11, 12, 13, 15, 131, and 131 in FIGS. 132, 133, 134, and 135 respectively correspond to the portions shown.

比較例１では、半導体層２３の上に形成する電極の構造を前記の実施例と異なるものとした。すなわち、比較例１では上部クラッド層２３５の表面に、厚さ５０ｎｍの金・ゲルマニウム合金を下層とし、厚さ８５０ｎｍの金を上層とする、前記の実施例で形成した台座電極と同じ直径を約１１０μｍとする円形のオーミック性の電極２８を形成した。電極２８は近接する相互の距離を５００μｍとし等間隔に半導体層２３の表面に配置した。 In Comparative Example 1, the structure of the electrode formed on the semiconductor layer 23 was different from that of the above-described example. That is, in Comparative Example 1, the same diameter as that of the pedestal electrode formed in the above-described embodiment, in which a 50 nm-thick gold-germanium alloy is used as a lower layer and a 850 nm-thick gold is used as an upper layer on the surface of the upper cladding layer 235, is used. A circular ohmic electrode 28 having a thickness of 110 μm was formed. The electrodes 28 were arranged on the surface of the semiconductor layer 23 at equal intervals with the distance between adjacent electrodes being 500 μm.

その後ダイシング法により、半導体層２３の表面から発光部を含む深さ１５μｍの範囲に切り込み２９を入れて発光面を分離し、さらにエッチングによりダイシングの切り込み２９に沿う破砕層を除去した。切り込み２９により分離された発光面は、図４に示すように一辺を約１０００μｍとする正方形とした。 Thereafter, the dicing method was used to cut the cut surface 29 from the surface of the semiconductor layer 23 to a depth of 15 μm including the light emitting portion to separate the light emitting surface, and further, the crushed layer along the dicing cut 29 was removed by etching. The light emitting surface separated by the cut 29 was a square having a side of about 1000 μm as shown in FIG.

その後実施例と同様にして、上記の電極２８を形成し切り込み２９を入れたエピタキシャルウェーハを、通常のスクライブ法により素子の形状に裁断して個別に細分化し、発光素子となした。比較例１のＬＥＤは、図５に示すように切り込み２９により分離した単位を４個まとめて正方形としたものであり、基板２１の部分ではつながっている。 Thereafter, in the same manner as in the example, the epitaxial wafer on which the above-mentioned electrodes 28 were formed and the cuts 29 were formed was cut into element shapes by a usual scribing method and individually divided into light-emitting elements. As shown in FIG. 5, the LED of Comparative Example 1 is a unit in which four units separated by cuts 29 are formed into a square, and are connected at the substrate 21 portion.

実施例と同様に、この発光素子を用いてＬＥＤを組み立てた。比較例１の発光素子は、台座電極が４つある為、４つの電極より１本ずつ、計４本の金線でワイヤボンドを行い、第２の電極端子に接続した。 As in the example, an LED was assembled using this light emitting element. Since the light-emitting element of Comparative Example 1 had four pedestal electrodes, wire bonding was performed with a total of four gold wires, one from each of the four electrodes, and connected to the second electrode terminal.

このＬＥＤの第１と第２の電極端子との間に順方向電流を流したところ、１Ａ通電時の順方向電圧が約３．７Ｖであり、実施例と同等であった。 When a forward current was passed between the first and second electrode terminals of this LED, the forward voltage when 1 A was applied was about 3.7 V, which was equivalent to that of the example.

また、比較例１の発光素子のＸ−Ｘ線上の発光強度のＬＥＤの発光面内での分布を測定した結果を図１１に示す。実施例に比較し、ＬＥＤの周縁部の発光強度が低下する傾向があり、またＬＥＤの上部に配設したオーミック性の影響によって、発光強度の面内分布に不均一を生じている。また、比較例１ののＬＥＤの輝度は１６００ｍｃｄであった。 FIG. 11 shows the results of measuring the distribution of the light emission intensity of the light emitting element of Comparative Example 1 on the line XX in the light emitting surface of the LED. Compared with the embodiment, the luminous intensity at the periphery of the LED tends to decrease, and the in-plane distribution of the luminous intensity is non-uniform due to the effect of the ohmic property provided above the LED. Further, the luminance of the LED of Comparative Example 1 was 1600 mcd.

（比較例２）比較例２では、上記の実施例と同じ構造の半導体層を形成したエピタキシャルウェーハを用いて、発光面積がほぼ同じ大きさの半導体発光素子を作製した。比較例２で作製した半導体発光素子を図６、図７に示す。 Comparative Example 2 In Comparative Example 2, a semiconductor light emitting device having a light emitting area of almost the same size was manufactured using an epitaxial wafer on which a semiconductor layer having the same structure as that of the above example was formed. 6 and 7 show the semiconductor light emitting device manufactured in Comparative Example 2. FIG.

図６は比較例２で作製した半導体発光素子の平面図、図７は図６のＩ−Ｉ線に沿った断面図である。図６、図７で符号３１，３２，３３，３５，３３１，３３２，３３３，３３４，３３５で示した部分は、図１、図２、図３の符号１１，１２，１３，１５，１３１，１３２，１３３，１３４，１３５で示した部分とそれぞれ対応する。 FIG. 6 is a plan view of the semiconductor light emitting device manufactured in Comparative Example 2, and FIG. 7 is a cross-sectional view taken along the line II of FIG. 6 and FIG. 7, the parts indicated by reference numerals 31, 32, 33, 35, 331, 332, 333, 334, and 335 are the reference numerals 11, 12, 13, 15, 131, and 131 in FIGS. 132, 133, 134, and 135 respectively correspond to the portions shown.

比較例２では、半導体層３３の上に形成する電極の構造を前記の実施例と異なるものとした。すなわち、比較例２では上部クラッド層３３５の表面の中心に厚さ５０ｎｍの金・ゲルマニウム合金を下層とし、厚さ８５０ｎｍの金を上層とする、前記の実施例で形成した台座電極と同じ直径を約１１０μｍとする円形のオーミック性の電極３８を１つ形成した。 In Comparative Example 2, the structure of the electrode formed on the semiconductor layer 33 was different from that of the above-described example. That is, in Comparative Example 2, the same diameter as that of the pedestal electrode formed in the above-described embodiment, in which a 50 nm-thick gold-germanium alloy is used as a lower layer and a 850 nm-thick gold is used as an upper layer at the center of the surface of the upper cladding layer 335. One circular ohmic electrode 38 having a thickness of about 110 μm was formed.

その後実施例と同様にして、上記の電極３８および透明導電膜３４を形成したエピタキシャルウェーハを、通常のスクライブ法により素子の形状に裁断して個別に細分化し、ＬＥＤとなした。 Thereafter, in the same manner as in the example, the epitaxial wafer on which the above-described electrodes 38 and the transparent conductive film 34 were formed was cut into individual device shapes by a normal scribing method, and individually divided into LEDs.

実施例と同様にして、ＬＥＤを組み立てた。そして、第１と第２の電極端子との間に順方向電流を流したところ、１Ａ通電時の順方向電圧が、４．５Ｖであった。また、比較例２のＬＥＤの発光強度のＬＥＤのＸ−Ｘ線上の発光面内での分布を測定した結果を図１１に示す。実施例に比較し、発光強度の面内分布に不均一を生じて、特に中央部と周辺部における輝度が低下した。これは、電極からの電流拡散が不十分で、半導体層へ流れる電流が面内で不均一となるためと考えられる。また、比較例２のＬＥＤの輝度は１２００ｍｃｄであった。 An LED was assembled in the same manner as in the example. Then, when a forward current was passed between the first and second electrode terminals, the forward voltage when 1 A was conducted was 4.5 V. FIG. 11 shows the result of measuring the distribution of the light emission intensity of the LED of Comparative Example 2 on the light emitting surface of the LED on the line XX. Compared to the example, the in-plane distribution of the light emission intensity was non-uniform, and the brightness particularly at the central portion and the peripheral portion was reduced. It is considered that this is because current diffusion from the electrode is insufficient and the current flowing to the semiconductor layer becomes non-uniform in the plane. Further, the luminance of the LED of Comparative Example 2 was 1200 mcd.

（比較例３）比較例３では、上記の実施例と同じ構造の半導体層を形成したエピタキシャルウェーハを用いて、発光面積がほぼ同じ大きさの半導体発光素子を作製した。比較例３で作製した半導体発光素子を図８、図９、図１０に示す。 Comparative Example 3 In Comparative Example 3, a semiconductor light emitting device having a light emitting area of almost the same size was manufactured using an epitaxial wafer on which a semiconductor layer having the same structure as that of the above example was formed. The semiconductor light emitting device manufactured in Comparative Example 3 is shown in FIGS.

図８は比較例３で作製した半導体発光素子の平面図、図９は図８のＩ−Ｉ線に沿った断面図、図１０は図９のＩ’−Ｉ’線に沿った断面図である。図８、図９、図１０で符号４１，４２，４３，４５，４３１，４３２，４３３，４３４，４３５で示した部分は、図１、図２，図３の符号１１，１２，１３，１５，１３１，１３２，１３３，１３４，１３５で示した部分と対応する。 8 is a plan view of the semiconductor light emitting device manufactured in Comparative Example 3, FIG. 9 is a cross-sectional view taken along the line II of FIG. 8, and FIG. 10 is a cross-sectional view taken along the line I′-I ′ of FIG. is there. 8, 9, and 10, portions denoted by reference numerals 41, 42, 43, 45, 431, 432, 433, 434, and 435 correspond to reference numerals 11, 12, 13, and 15 in FIGS. 1, 2, and 3. , 131, 132, 133, 134, and 135.

比較例３では、半導体層４３の上に形成する電極の構造を前記の実施例と異なるものとした。すなわち、比較例３では上部クラッド層４３５の表面の隅部に厚さ５０ｎｍの金・ゲルマニウム合金を下層とし、厚さ８５０ｎｍの金を上層とする、前記の実施例で形成した台座電極と同じ直径を約１１０μｍとする円形のオーミック性の電極４８を１つ形成した。 In Comparative Example 3, the structure of the electrode formed on the semiconductor layer 43 was different from that of the above-described example. That is, in Comparative Example 3, the same diameter as that of the pedestal electrode formed in the above-described embodiment, in which a 50 nm-thick gold-germanium alloy is used as a lower layer and a 850 nm-thick gold is used as an upper layer at a corner of the surface of the upper cladding layer 435. Of about 110 μm was formed.

その後実施例と同様にして、上記の電極４８および透明導電膜４４を形成した
エピタキシャルウェーハを、通常のスクライブ法により素子の形状に裁断して個別に細分化し、ＬＥＤとなした。 Thereafter, in the same manner as in the example, the epitaxial wafer on which the above-described electrodes 48 and the transparent conductive film 44 were formed was cut into element shapes by a normal scribing method, and individually divided into LEDs.

実施例と同様にして、ＬＥＤを組み立てた。そして、第１と第２の電極端子との間に順方向電流を流したところ、１Ａ通電時の順方向電圧が、４．２Ｖであった。また、比較例３のＬＥＤの発光強度のＬＥＤのＸ−Ｘ線上の発光面内での分布を測定した結果を図１１に示す。実施例に比較し、発光強度の面内分布に不均一を生じて、特に台座電極から遠い領域での輝度が低下した。これは、電極からの電流拡散が不十分で、半導体層へ流れる電流が面内で不均一となるためと考えられる。また、比較例３のＬＥＤの輝度は１８００ｍｃｄであった。 An LED was assembled in the same manner as in the example. Then, when a forward current was passed between the first and second electrode terminals, the forward voltage when 1 A was conducted was 4.2 V. FIG. 11 shows the results of measuring the distribution of the light emission intensity of the LED of Comparative Example 3 on the light emitting surface of the LED on the line XX. Compared to the example, the in-plane distribution of the luminous intensity was non-uniform, and the luminance particularly in a region far from the pedestal electrode was reduced. It is considered that this is because current diffusion from the electrode is insufficient and the current flowing to the semiconductor layer becomes non-uniform in the plane. Further, the luminance of the LED of Comparative Example 3 was 1800 mcd.

本発明の半導体発光素子の概略構成を示す平面図である。FIG. 1 is a plan view illustrating a schematic configuration of a semiconductor light emitting device of the present invention. 図１のＩ−Ｉ線断面を示す図である。FIG. 2 is a diagram illustrating a cross section taken along line II of FIG. 1. 図１のＩ’−Ｉ’線断面を示す図である。FIG. 2 is a diagram illustrating a cross section taken along line I′-I ′ of FIG. 1. 比較例１で作製した半導体発光素子の平面図である。FIG. 4 is a plan view of a semiconductor light emitting device manufactured in Comparative Example 1. 図４のＩ−Ｉ線に沿った断面図である。FIG. 5 is a sectional view taken along the line II of FIG. 4. 比較例２で作製した半導体発光素子の平面図である。13 is a plan view of a semiconductor light emitting device manufactured in Comparative Example 2. FIG. 図６のＩ−Ｉ線に沿った断面図である。FIG. 7 is a sectional view taken along the line II of FIG. 6. 比較例３で作製した半導体発光素子の平面図である。13 is a plan view of a semiconductor light emitting device manufactured in Comparative Example 3. FIG. 図８のＩ−Ｉ線に沿った断面図である。FIG. 9 is a sectional view taken along the line II of FIG. 8. 図８のＩ’−Ｉ’線に沿った断面図である。FIG. 9 is a sectional view taken along the line I′-I ′ of FIG. 8. 実施例、比較例１，２，３の発光強度分布を示す図である。It is a figure which shows the light emission intensity distribution of an Example and Comparative Examples 1, 2, and 3.

Explanation of reference numerals

１１半導体基板
１２発光部
１３半導体層
１３１緩衝層
１３２光反射層
１３３下部クラッド層
１３４発光層
１３５上部クラッド層
１４透明導電膜
１５第１の電極
１６台座電極
１７分配電極 Reference Signs List 11 semiconductor substrate 12 light emitting section 13 semiconductor layer 131 buffer layer 132 light reflecting layer 133 lower cladding layer 134 light emitting layer 135 upper cladding layer 14 transparent conductive film 15 first electrode 16 pedestal electrode 17 distribution electrode

Claims

A semiconductor substrate having a first electrode formed on the back surface, a semiconductor layer including a light emitting portion formed on the semiconductor substrate, and an ohmic contact with the semiconductor layer distributed over a part of the surface of the semiconductor layer; A distribution electrode that makes contact, a transparent conductive film that is formed over the surface of the semiconductor layer and the distribution electrode and conducts with the distribution electrode, and a transparent conductive film that is formed on part of the surface of the transparent conductive film. In a semiconductor light emitting device having a conductive base electrode,
One side of a surface (light emitting surface) of the semiconductor layer from which light is extracted is 0.8 mm or more, and a plurality of pedestal electrodes are arranged in a region within 0.3 mm from the outer periphery of the transparent conductive film.
A semiconductor light emitting device characterized by the above-mentioned.

The semiconductor light emitting device according to claim 1, wherein a region of the light emitting surface that blocks light emission is 30% or less of a surface area of the device upper surface.

3. The semiconductor according to claim 1, wherein the distribution electrode is formed by forming a linear electrode having a line width of 0.030 mm or less in a lattice shape, and is made of metal and has a thickness of 0.50 μm or less. 4. Light emitting element.

4. The semiconductor light emitting device according to claim 1, wherein said pedestal electrodes are arranged at four corners of a surface of the transparent conductive film.

5. The semiconductor light emitting device according to claim 1, wherein the transparent conductive film is made of indium tin oxide (ITO).

6. The semiconductor light emitting device according to claim 1, wherein a forward voltage at the time of applying one ampere is 4.00 V or less.

The semiconductor light emitting device according to claim 1, wherein the light emitting unit is made of AlGaInP.

The semiconductor light emitting device according to claim 1, wherein the light emitting unit is formed by a MOCVD method.

A light-emitting diode using the semiconductor light-emitting device according to claim 1.

A light emitting diode using the semiconductor light emitting device according to claim 1, wherein a plurality of wires are provided by wire bonding.