JPS58197787A - Semiconductor laser - Google Patents

Semiconductor laser

Info

Publication number
JPS58197787A
JPS58197787A JP7937282A JP7937282A JPS58197787A JP S58197787 A JPS58197787 A JP S58197787A JP 7937282 A JP7937282 A JP 7937282A JP 7937282 A JP7937282 A JP 7937282A JP S58197787 A JPS58197787 A JP S58197787A
Authority
JP
Japan
Prior art keywords
layer
groove
active layer
shallow
deep
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.)
Pending
Application number
JP7937282A
Other languages
Japanese (ja)
Inventor
Shinsuke Ueno
上野　「あ」資
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
NEC Corp
Original Assignee
NEC Corp
Nippon Electric Co Ltd
Priority date (The priority date 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 date listed.)
Filing date
Publication date
Application filed by NEC Corp, Nippon Electric Co Ltd filed Critical NEC Corp
Priority to JP7937282A priority Critical patent/JPS58197787A/en
Publication of JPS58197787A publication Critical patent/JPS58197787A/en
Pending legal-status Critical Current

Links

Classifications

    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01S—DEVICES USING THE PROCESS OF LIGHT AMPLIFICATION BY STIMULATED EMISSION OF RADIATION [LASER] TO AMPLIFY OR GENERATE LIGHT; DEVICES USING STIMULATED EMISSION OF ELECTROMAGNETIC RADIATION IN WAVE RANGES OTHER THAN OPTICAL
    • H01S5/00—Semiconductor lasers
    • H01S5/10—Construction or shape of the optical resonator, e.g. extended or external cavity, coupled cavities, bent-guide, varying width, thickness or composition of the active region
    • H01S5/16—Window-type lasers, i.e. with a region of non-absorbing material between the active region and the reflecting surface
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01S—DEVICES USING THE PROCESS OF LIGHT AMPLIFICATION BY STIMULATED EMISSION OF RADIATION [LASER] TO AMPLIFY OR GENERATE LIGHT; DEVICES USING STIMULATED EMISSION OF ELECTROMAGNETIC RADIATION IN WAVE RANGES OTHER THAN OPTICAL
    • H01S5/00—Semiconductor lasers
    • H01S5/20—Structure or shape of the semiconductor body to guide the optical wave ; Confining structures perpendicular to the optical axis, e.g. index or gain guiding, stripe geometry, broad area lasers, gain tailoring, transverse or lateral reflectors, special cladding structures, MQW barrier reflection layers
    • H01S5/24—Structure or shape of the semiconductor body to guide the optical wave ; Confining structures perpendicular to the optical axis, e.g. index or gain guiding, stripe geometry, broad area lasers, gain tailoring, transverse or lateral reflectors, special cladding structures, MQW barrier reflection layers having a grooved structure, e.g. V-grooved, crescent active layer in groove, VSIS laser

Landscapes

  • Semiconductor Lasers (AREA)

Abstract

PURPOSE:To obtain a semiconductor laser enabling fundamental lateral mode to oscillate remarkable light output at low threshold value by a method wherein a groove deep at central part and shallow at both ends provided in the longitudinal direction of a resonator of a semiconductor with forbiden band width narrower than oscillating wave length making use of optical transmission and absorption actions. CONSTITUTION:An SiO2 mask 11 is provided on (100) surface of N type GaAs substrate 10 to be an absorbing body of specified wave length and anisotropically etched forming a V groove deep at central part and shallow at both ends. The mask 11 is removed to be embedded with N type Al0.4Ga0.6 As 12 layer also depositing on the flat part while the deep groove surface of layer 12 reaches the level around half depth of the shallow groove with the wall surface also covered with the layer 12. Al0.15Go0.85As active layer 13 with no additive is laminated locating its height in the shallow groove of the layer 12. The active layer on shallow groove and the active layer on deep groove are separated from each other due to the inverse mesa type of the groove in the longitudinal direction of a resonator. Next the deep groove is embedded with P type Al0.4Ga0.6As layer 14 and N type Al0.02Ga0.98As layer 15 and SiO2 layer 16 are laminated on the flat surface and a hole is opened to provide Zn diffusion layer reaching the layer 14 with ohmic electrodes 18, 19 provided completing a semiconductor laser. The active layer with central deep groove may condense light oscillating the light output stably.

Description

【発明の詳細な説明】 本発明は半導体レーザ特に大光出力半導体レーザに関す
るものである。DETAILED DESCRIPTION OF THE INVENTION The present invention relates to semiconductor lasers, particularly high optical output semiconductor lasers.

ＡＪＧａＡｓ／ＧａＡ１等の結晶材料を用いる可視光半
導体レーザは低閾値で高効率の室温連続発振を行うこと
ができるので光方式のディジタル・オーディオ・ディス
ク（ＤＡＤ）用光源として最適であり実用化されつつあ
る。更にこの可視光半導体レーザは光プリンタ等の光書
きこみ用光源としてのｗＩ！も高まり、この要求をみた
すため大光出力発振に耐える可視光半導体レーザの研究
開発が進められている。Visible light semiconductor lasers using crystalline materials such as AJGaAs/GaA1 can perform continuous oscillation at room temperature with low threshold and high efficiency, making them ideal as light sources for optical digital audio disks (DAD), and are being put into practical use. be. Furthermore, this visible light semiconductor laser can be used as a light source for optical writing in optical printers, etc. In order to meet this demand, research and development is underway on visible light semiconductor lasers that can withstand high optical output oscillation.

ところでストライプ幅１０〜２０μｍのＡＡ！ＧａＡｓ
／ＧａＡｓ半導体レーザでは室温連続発振（ＣＷ）光出
力Ｉ　Ｑ　ｍＷ、パルス動作（１００ｎｓ幅）光出力１
００ｍＷ１ｉＩＪｉ［が動作限界であり、これ以上の光
出力を放出すると容易に反射面が破壊される。この現象
は古くから光学損傷として知られてお９．ＣＷ動作の限
界光出力密ｆは１ＭＷ／ｄ前後である。これ迄大光出力
を得るためＫＦ１反射面での光出力密度を下げる試みが
なされている。即ちストライプ幅の拡大、活性層厚の拡
大、二重ダブルへテロ構造等が報告されている。この場
合必ず１−値電流密度の増加を伴い室温連続発振を困難
にさせた。また大光出力動作させると、たとえストライ
プ幅が狭くても発振領域が拡、が９水平横モード（活性
層に平行な方向の横モード）は複雑な多モードと化した
。このため大光出力動作体レーザの用途は障害物検知等
に限られ、レーザプリンタ等の新しい用途は実現されて
いない。By the way, AA has a stripe width of 10 to 20 μm! GaAs
/GaAs semiconductor laser has room temperature continuous wave (CW) optical output I Q mW, pulse operation (100 ns width) optical output 1
00 mW1iIJi[ is the operating limit, and if more light output is emitted, the reflective surface will be easily destroyed. This phenomenon has long been known as optical damage9. The critical optical power density f of CW operation is around 1 MW/d. Until now, attempts have been made to lower the optical output density at the KF1 reflecting surface in order to obtain a large optical output. That is, enlarged stripe width, enlarged active layer thickness, double double heterostructure, etc. have been reported. In this case, the one-value current density always increased, making continuous oscillation at room temperature difficult. Furthermore, when operated with high optical power, the oscillation region expanded even if the stripe width was narrow, but the 9-horizontal transverse mode (transverse mode in the direction parallel to the active layer) became a complex multi-mode. For this reason, the use of high-light output operating body lasers is limited to obstacle detection, etc., and new uses such as laser printers have not been realized.

これに対し反射面近傍Ｋｔ；を電流を流さず非励起状態
にし、中央部のストライプ領域にのみ電流を流して励起
領域とし、反射面近傍がレーザ光に対し透明な非励起領
域となる構造のストライプ半導体レーザが本発明者達の
特願ａ８５３−１８８８２に提案されている。On the other hand, a structure in which the vicinity of the reflective surface Kt; is kept in a non-excited state without passing any current, and the striped region in the center is made into an excited region by passing a current through it, and the vicinity of the reflective surface becomes a non-excited region that is transparent to the laser beam. A striped semiconductor laser has been proposed in Japanese Patent Application No. A853-18882 by the inventors.

ＡｊＧａＡｓ　／　ＧａＡｓダブルへテロ接合構造の場
合を例にその一例を示すと励起領域をと９かこむ非励起
領域の活性層をｎ形にし活性層の励起領域となる部分を
Ｚｎ拡散等でストライプ状にｐ形にすると、励起領域の
バンドギャップに対して非励起・ト 領域のバンドギャップは約３０〜５０　ｍｅＶ　＠ｐす
る。この場合ｎ形濃度が高くｐ形濃度が高い程バンドギ
ャップの相対的な責化量は大きい。従って励起領域で生
じたレーザ光に対して非励起領域はほぼ透明になる。本
発明者等は上記の構造において光学損傷は従来の限界光
出力の５倍をこえても尚発生しない事を見出した。非励
起領域は小数キャリアの拡散長以上長ければ充分効果を
示し、かつこれらの効果はダブルへテロ接合構造に限ら
れる事も確−された。To give an example of the case of AjGaAs/GaAs double heterojunction structure, the active layer of the non-excited region surrounding the excitation region is made n-type, and the part of the active layer that will become the excitation region is made into stripes by Zn diffusion, etc. When the p-type is used, the band gap of the non-excited/t region is about 30 to 50 meV @p with respect to the band gap of the excited region. In this case, the higher the n-type concentration and the higher the p-type concentration, the greater the relative contribution of the band gap. Therefore, the non-excited region becomes almost transparent to the laser beam generated in the excitation region. The present inventors have found that in the above structure, optical damage does not occur even when the optical output exceeds five times the conventional limit optical output. It has been confirmed that sufficient effects are exhibited as long as the non-excitation region is longer than the diffusion length of minority carriers, and that these effects are limited to double heterojunction structures.

しかし、上記構造の半導体レーザは励起領域が不純物補
償されたｐ形になっており内部吸収損失が大きく＠値ｉ
ｍ流が高くなる傾向があるばかりでなく拡散長が短くな
るため高次横モードの利得の上昇が大きく素子本来の目
的とした大光出力動作時では水平横モードが高次多モー
ド化する欠点があった。その上レーザ光が非励起領域を
伝播する場合には光はガウス分布状に広がりながら伝播
するため反射面で反射されて賜どってきた光が再び励起
領域にはい９レ一ザ発振に必要な利得の増大に寄与する
割合（カップリング効率）は低くなり、その九め損失が
大きくなり閾値電流が上昇し外部微分量子効率が低下す
る等の欠点をもっていた。However, in the semiconductor laser with the above structure, the excitation region is p-type with impurity compensation, and internal absorption loss is large @ value i
The drawback is that not only does the m current tend to increase, but also that the diffusion length becomes short, resulting in a large increase in the gain of higher-order transverse modes.When the device is operating at a high light output, which is the original purpose of the device, horizontal transverse modes become higher-order multimodes. was there. Furthermore, when the laser light propagates through the non-excitation region, the light propagates while spreading in a Gaussian distribution, so the light that has been reflected by the reflective surface returns to the excitation region and is necessary for laser oscillation. The ratio contributing to the increase in gain (coupling efficiency) is low, the loss is large, the threshold current is increased, and the external differential quantum efficiency is decreased.

父上記構造とは別に反射面近傍を活性層上９もバンドギ
ャップの大きいクラッド層で埋込む方法が提案されてい
る。しかしこの場合にも上記構造と同様にレーザ光がク
ラッド層を伝播する１ｌｊＫ元は広がりカップリング効
率が低くなる為閾値電流の上昇及び外部微分量子効率の
低下をきたす欠点を有しているのみならず、結晶成長し
た後エツチングをして反射面となる領域をクラッドｆ−
で埋込むなど製法が複雑であり、更に埋込んだクラッド
層領域と活性層との界面部分に結晶欠陥が生じやすく信
頼性の点で問題がある等の種々の欠点を有していえ。In addition to the above-mentioned structure, a method has been proposed in which the vicinity of the reflective surface is also filled with a cladding layer having a large band gap above the active layer 9. However, in this case as well, as in the above structure, the 1ljK element in which the laser light propagates through the cladding layer spreads and the coupling efficiency decreases, resulting in an increase in threshold current and a decrease in external differential quantum efficiency. First, after crystal growth, the area that will become the reflective surface is etched to form a clad f-
However, the manufacturing method is complicated, such as embedding the cladding layer region with the active layer, and crystal defects are likely to occur at the interface between the buried cladding layer region and the active layer, resulting in problems in terms of reliability.

本発明の目的は上記諸欠点を除去し低閾値で発振するの
みならず基本横モード発振による大光出力発振が可能で
あり更に一一成喪で製作でき再現性およびｉｇｓ性のう
えですぐれた半導体レーザを提供する事にある。The purpose of the present invention is to eliminate the above-mentioned drawbacks, to enable not only oscillation with a low threshold value but also large optical output oscillation due to fundamental transverse mode oscillation, and furthermore, it can be manufactured in a single process and has excellent reproducibility and IGS performance. Our goal is to provide semiconductor lasers.

本発明の半導体レーザは発振波擾よりもバンドギャップ
の狭い半導体に共振器長方向に内反射面近傍では浅く中
央部分では深い溝を形成し、この半導体上に＠記両反射
面近傍の浅い溝を埋込む第１のクラッド層、これに隣接
した活性層、前記深い溝を壌込む第２のクラッド層、キ
ャップ層を積層して多層構造を形成し、前記深い溝の活
性層の深さ方向の位置が前記内反射面近傍の浅い溝の内
部にあると共に前記深い溝の活性層と前記浅い溝の活性
層とが少くとも同一平面になく１前記深い溝の活性層上
のキャップ層に電流注入領域を設けた事を特徴とする構
造を有している。In the semiconductor laser of the present invention, grooves are formed in a semiconductor having a narrower bandgap than the oscillation waveform in the cavity length direction, shallow in the vicinity of the internal reflection surface and deep in the central part, and on this semiconductor, shallow grooves are formed in the vicinity of both reflection surfaces. A first cladding layer that buries the deep groove, an active layer adjacent thereto, a second cladding layer that burrows into the deep groove, and a cap layer are laminated to form a multilayer structure, and the depth direction of the active layer in the deep groove is stacked. is located inside the shallow groove near the internal reflection surface, and the active layer of the deep groove and the active layer of the shallow groove are at least on the same plane. It has a structure characterized by providing an injection region.

本発明の原理はバンドギャップ差圧よる光の透過現象と
吸収現象とを応用したものである。The principle of the present invention is based on the application of light transmission and absorption phenomena caused by bandgap differential pressure.

本発明はたとえば発振波長０，７μｍＷ！に対するＧａ
Ａｓ基板の如く発振波長に対して吸収体となる層の（１
００）面上で共振器長方向＜０１１＞に内反射面近傍部
分の幅を狭くしたストライプ状の窓を形成しＢｒとメチ
ルアルコールとの混合溶液等のエツチング液を用いてエ
ツチングすると（１１１）Ａ面を両壁面とする■溝が形
成される。ＶＳＵ−足形成されるとその後はエツチング
されずその深さは平面に対して５４ｆ１６分の両（１１
１）Ａ面が交わる位置に固定される。従ってエツチング
はストライプ＃ＡＫのみ依存しきわめて安定に形成され
るので本構造ではストライプ状の窓の溝に応じて共振器
の中央部分が深く内反射面近傍が浅い溝が安定にかつ再
現性よく形成される。その後吸収層と同一の導電性を有
する第１のクラッド層、活性層％吸収層と逆の導電性を
有する第２のクラッド層、更に第２のクラッド層と逆の
導電性を有するキャップ層を連続成長する。For example, the oscillation wavelength of the present invention is 0.7 μmW! Ga for
(1
When a striped window with a narrow width near the internal reflection surface is formed on the resonator length direction <011> on the 00) surface and etched using an etching liquid such as a mixed solution of Br and methyl alcohol (111) A groove is formed with side A as both wall surfaces. Once the VSU foot is formed, it is not etched and its depth is 54f16 (11
1) It is fixed at the position where the A plane intersects. Therefore, the etching depends only on the stripe #AK and is formed very stably, so in this structure, the grooves are deep in the center of the resonator and shallow near the internal reflection surface, and are formed stably and reproducibly in accordance with the grooves in the striped window. be done. Thereafter, a first cladding layer having the same conductivity as the absorption layer, a second cladding layer having the opposite conductivity to the active layer, and a cap layer having the opposite conductivity to the second cladding layer are formed. Continuous growth.

上記成長に際して溝内部の成長速ｆｔｉ郷外部の燃 平菖面に対して数倍速いのでこの事を利用して第は溝全
体を堀めかつ溝外部の平置な吸収層上では薄くなるよう
に成長させる。このとき共振器中央部分の深い溝領域で
はクラッド層は溝の中央部分を反射面近傍の浅い溝の少
くとも先端と同一位置Ｋまでうめつくすと共に■溝の壁
面ＶＣ旧って成長次いで、この第１のクラッド層に隣接
して成長する活性層は共振器中央部分ではクラッド層に
沿って成長する。このとき平面上の成長厚が薄くなるよ
うに制御すると活性層は■溝内部中央に主に成長しＶ溝
斜面上ではとぎれるかもしくはうすく成長し平面上の層
厚もうすくなる。前記クラッド層の成長面の制御により
この深い■溝中央部分の活性層の深さ方向の位置は反射
面近傍の浅い溝内部のクラッド層の一部分に一致する。During the above growth, the growth rate inside the groove is several times faster than on the flattened irises outside the groove, so by taking advantage of this fact, the first method is to dig the entire groove and make it thinner on the flat absorbing layer outside the groove. to grow. At this time, in the deep groove region in the central part of the resonator, the cladding layer fills the central part of the groove to at least the same position K as the tip of the shallow groove near the reflecting surface, and grows on the groove wall surface VC, and then grows on the groove wall surface VC. The active layer grown adjacent to one cladding layer grows along the cladding layer in the central portion of the cavity. At this time, if the growth thickness on the plane is controlled to be thin, the active layer mainly grows in the center of the inside of the groove, and on the slope of the V-groove, it is interrupted or grows thinly, and the layer thickness on the plane becomes smaller. By controlling the growth surface of the cladding layer, the position in the depth direction of the active layer at the center of the deep groove coincides with a portion of the cladding layer inside the shallow groove near the reflective surface.

これに対して共振器近傍の浅い溝の部分では活性層は溝
の上部に一定の層厚で成長する。この状ＩＩにおいて第
２のクラッド層で中央部分の深い溝を含めて全領域が一
様に埋込まれるようにする。その後連続して成長したキ
ャップ層のうち深い溝の上に位置する領域にのみ第２の
クラッド層と同じ導電性を有する不純物を拡散して電流
注入領域を設けると本発明の構造ができる。上記は■＃
Ｉについて説明したが溝は他の形状でもよい。On the other hand, in the shallow trench portion near the resonator, the active layer grows at a constant thickness above the trench. In this state II, the entire region including the deep groove in the central portion is filled uniformly with the second cladding layer. Thereafter, the structure of the present invention is obtained by diffusing impurities having the same conductivity as the second cladding layer only in the region of the continuously grown cap layer located above the deep trench to provide a current injection region. The above is ■#
Although the grooves have been described in terms of I, the grooves may have other shapes.

本発明の構造においてキャリア注入領域から深い溝部分
の活性層に注入されたキャリアによる発光のうち活性層
から第１のクラッド層にしみ出た光は吸収層で吸収され
大きな損失をうけるので深い溝内部の中央部分以外の活
性層からの発光は吸収層に吸収され損失となる。例えば
ｕＣｈＡＶ′０ａＡｓ系可視光レーザを例にとると発振
波長０．７８μｍに対して（ＪａＡｓ基板による吸収損
失は数千ＣＩＬ−’から１〜２万ｃＩＬ−１におよぶ。In the structure of the present invention, among the light emitted by carriers injected from the carrier injection region into the active layer in the deep groove portion, the light that seeps from the active layer into the first cladding layer is absorbed by the absorption layer and suffers a large loss. Light emitted from the active layer other than the central part of the interior is absorbed by the absorption layer and becomes a loss. For example, in the uChAV'0aAs visible light laser, the absorption loss due to the JaAs substrate ranges from several thousand CIL-1 to 10,000 to 20,000 CIL-1 for an oscillation wavelength of 0.78 μm.

これに対して深い溝の中央部分の活性層の光は吸収をう
けないので活性層水平横方向にわたって利得と損失のき
わめて大きなステップが生じる。更に本構造では溝の中
央部分の活性層は厚いので活性層中央部分の屈折率が等
価的に高くなり光は屈折率の高い中央部分に集光するた
め安定な基本横モード発振が維持される。On the other hand, since the light in the active layer in the central part of the deep groove is not absorbed, extremely large steps in gain and loss occur in the horizontal and lateral directions of the active layer. Furthermore, in this structure, since the active layer in the central part of the groove is thick, the refractive index of the central part of the active layer is equivalently high, and light is focused on the central part with a high refractive index, so stable fundamental transverse mode oscillation is maintained. .

上記の状態において活性層は深い婢の内部以外に浅い溝
領域にも形成されるが％４共振器長方向の溝の深さの差
による段差は逆メサ状になるので段差が大きい場合には
活性層にその部分でとぎれて成長しやすい。又一方活性
層がつながっていても浅い溝領域の活性層は非励起領域
となっているので深い溝から浅い溝の活性層内を通る光
は１５９ｃｉｉ−’から２ＱＱｃｍ−１にわたる吸収損
失をうけるためレーザ発振光のパスとにならず光の大部
分は深い溝の活性層励起領域から直進してレーザ発振を
開始する。この時直進した光はその反射面となる両端面
近傍でＦｉＭｌのクラッド層内を通る事になり例えばＡ
１ＧａＡｓ　／　ＧａＡｓ系可視光レーザを例にとると
発振波長０．７８μｍとＡＪＸ　Ｇａ１−ｘＡｓ　（ｘ
＝０．４　）クラッド層とのエネルギー差ｔ！３３０ｍ
ｅＶ以上になり第１のクラッド層での吸収損失は全く無
視でき低閾値で発振する事ができる。In the above state, the active layer is formed not only inside the deep trench but also in the shallow trench region, but the step due to the difference in trench depth in the cavity length direction becomes an inverted mesa shape, so if the step is large, It is easy to break off and grow in the active layer at that part. On the other hand, even if the active layer is connected, the active layer in the shallow groove region is a non-excited region, so light passing from the deep groove to the active layer in the shallow groove suffers an absorption loss ranging from 159cii-' to 2QQcm-1. Most of the light does not become a path for the laser oscillation light, but travels straight from the active layer excitation region of the deep groove and starts laser oscillation. At this time, the light traveling straight passes through the cladding layer of FiMl near both end faces that become the reflecting surfaces, so for example, A
Taking a 1GaAs/GaAs visible light laser as an example, the oscillation wavelength is 0.78 μm and AJX Ga1-xAs (x
=0.4) Energy difference with the cladding layer t! 330m
eV or more, absorption loss in the first cladding layer can be completely ignored and oscillation can be performed at a low threshold.

ところでレーザ光はクラッド層を通る際に水平横方向、
垂直方向ともに広がって進行する。しかし本発明の構造
では光のパスとなる第１のクラッド層は光に対して数千
１−１から１〜２万（ｍ”の損失となる吸収層に設けた
浅い溝内に成長してお９更にこのクラッド層に隣接して
光に対して１５ｏＣＩＩＬ−’〜２００ｍ−″１の損失
を有する非励起領域の活性層が成長しているので浅い溝
内の第１クラッド層は光に対する吸収層でかこまれてい
る。従って第１クラッド層を通る際に広がった光は吸収
層に吸収され発振光のスポットサイズは第１のクラッド
層の形状に規定されるｌＫになる。特に本構造でｔユ深
い溝内部の活性層の位置ｔま浅い溝の内部の深さＶＣく
る必要があるが浅い溝によってレーザ発振光の光の広が
りを制御できるのみならず浅い溝の形状によってレーザ
発振光を円形に近いスポットサイズに変換する事ができ
レーザ発振特性を著しく同上させる事ができる。すなわ
ち本発明の構造では共振器方向に発振スポットサイズを
規定する損失領域をともなっており一旦円形状のレーザ
発掘が生じるとこの形状を保ったまま安定な発振を維持
し 一嘔ける。％に本発明の構造では正の屈折率カイティン
グ機構をもつのみならず大きな利得損失ステ１ｒｌ ツブをともなっているので発振領域の幅をキャリアの拡
散長の２倍程度以下にしておけば一次横モードの利得の
上昇を抑圧する事ができ安定な基本横モード発振を維持
し続ける事ができる。By the way, when the laser beam passes through the cladding layer, it moves horizontally and horizontally.
It spreads and progresses both vertically. However, in the structure of the present invention, the first cladding layer, which serves as the optical path, is grown in a shallow groove provided in the absorption layer, which causes a loss of several thousand to 10,000 to 20,000 (m) to the light. Furthermore, since an active layer in a non-excited region with a loss of 15oCIIL-'~200m-''1 for light is grown adjacent to this cladding layer, the first cladding layer in the shallow groove absorbs light. Therefore, the light that spreads when passing through the first cladding layer is absorbed by the absorption layer, and the spot size of the oscillated light becomes lK, which is defined by the shape of the first cladding layer.Especially in this structure, The position of the active layer inside the deep groove must be equal to the depth VC inside the shallow groove, but the shallow groove not only allows the spread of the laser oscillation light to be controlled, but also the shape of the shallow groove allows the laser oscillation light to be controlled. The spot size can be converted to a nearly circular spot size, and the laser oscillation characteristics can be significantly improved.In other words, the structure of the present invention has a loss region that defines the oscillation spot size in the direction of the resonator, and once the circular laser is excavated. When this occurs, stable oscillation is maintained while maintaining this shape, resulting in a complete oscillation.In addition, the structure of the present invention not only has a positive refractive index kiting mechanism, but also has a large gain loss step 1rl, which prevents oscillation. By setting the width of the region to about twice the carrier diffusion length or less, it is possible to suppress the increase in the gain of the primary transverse mode and to continue to maintain stable fundamental transverse mode oscillation.

本発明の如く両端面近傍をレーザ発振光が透過するクラ
ッド層にする事は反射面破壊（ＣＯＤ）しばルを飛躍的
に上昇さ姥る事ができる。すなわち通常の半導体レーザ
ではキャリア注入による励起領域となる活性層端面が反
射面として篇出してお９、そこでは表面再結合が生じ空
乏層化してパンツト ドギャップが縮Ｉしている。従って大光出力発振ノＪ〜 をさせるとこの縮夕したバンドギャップにより光の吸収
が生じそこは発熱して融点近くオで温度が上昇し、つい
には光学損傷が生じる。これに対し本発明の構造では光
の反射面となる両端面近傍は非励起領域になっているば
かりでなく発振光はバンドギャップ差が２００〜３００
ｍｅＶ以上も広いクラッド層を透過して発振するので反
射面近傍での光の吸収はなく光学損傷は生じにくいので
大光出力発振が可能にヶや。By making the vicinity of both end faces a cladding layer through which laser oscillation light passes, as in the present invention, the probability of failure of the reflective surface (COD) can be dramatically increased. That is, in a normal semiconductor laser, the end face of the active layer, which becomes an excitation region due to carrier injection, is set out as a reflective surface 9, where surface recombination occurs and becomes a depletion layer, causing the shortened gap to shrink. Therefore, when a large optical output oscillation is performed, light is absorbed by this narrowed band gap, which generates heat and the temperature rises near the melting point, eventually causing optical damage. On the other hand, in the structure of the present invention, not only the vicinity of both end faces, which are light reflecting surfaces, are non-excited regions, but also the oscillated light has a band gap difference of 200 to 300.
Since it oscillates through a cladding layer that is wider than meV, there is no absorption of light near the reflective surface and optical damage is less likely to occur, making it possible to oscillate a large optical output.

ところで上記に述べ九本発明の構造は本発明と類似した
層構造を有し共振器長方向の中央部分に浅く両端面近傍
に深い溝を形成したレーザとは全くＳなっている。すな
わち本発明の構造では発振有している。更に反射面近傍
の第１クラッド層のまわりがレーザ光の吸収層となりこ
の領域が光のガイド領域となり円形に近い発振が生じる
。これに対して反射面近傍が深い溝となっている場合に
はレーザ光はクラッド層を透過する際に広がるばかりで
なく特に垂直方向は大きな広がり角となり平偏なスポッ
トサイズになる。By the way, the structure of the present invention described above has a layer structure similar to that of the present invention, and is completely different from the laser in which a shallow groove is formed in the central portion in the longitudinal direction of the cavity and a deep groove is formed near both end faces. That is, the structure of the present invention has oscillation. Further, the area around the first cladding layer in the vicinity of the reflective surface becomes a laser beam absorption layer, and this area becomes a light guide area, causing near-circular oscillation. On the other hand, when the vicinity of the reflective surface is a deep groove, the laser light not only spreads when passing through the cladding layer, but also has a large spread angle particularly in the vertical direction, resulting in a flat spot size.

以上に説明したように本発明による半導体レーザは次の
ような効果をもつ。As explained above, the semiconductor laser according to the present invention has the following effects.

励起領域が直接反射面に露出している通常の半導体レー
ザにくらべて外部との化学反応はおこ９に（〈反射面の
光学反応による劣化を阻止する事ができる。Compared to a normal semiconductor laser in which the excitation region is directly exposed to the reflective surface, chemical reactions with the outside occur less frequently (deterioration due to optical reactions on the reflective surface can be prevented).

反射面近傍は発振光に対してバンドキャップがきわめて
広いクラッド層になっているので光の吸収は少なく光学
損傷は発生せず大光出力発振が可能になる。Since the cladding layer near the reflective surface has an extremely wide bandgap relative to the oscillated light, light absorption is small and optical damage does not occur, making it possible to oscillate a large optical output.

本発明の構造でにレーザ光は反射面近傍に設けた吸収層
による光ガイド機構によって円形に近い光源となり光学
系へのカップリング効率が上昇する。In the structure of the present invention, the laser beam becomes a nearly circular light source due to the light guide mechanism using the absorption layer provided near the reflective surface, and the coupling efficiency to the optical system increases.

本発明の構造では活性層の層厚の変化にもとすく正の実
効的な屈折率ガイディング機構をもち安定な基本横モー
ド発振を維持し続ける事ができる。The structure of the present invention has a positive effective refractive index guiding mechanism and can continue to maintain stable fundamental transverse mode oscillation even when the layer thickness of the active layer changes.

溝を形成した層上に一度の結晶成長で製作する事ができ
又溝の形成も容易であり再現性よくかつ高歩留りに製作
する事ができる。It can be manufactured by one-time crystal growth on a layer in which grooves are formed, and the grooves can be easily formed and manufactured with good reproducibility and high yield.

以下図面を用いて本発明の一実施例を説明する。An embodiment of the present invention will be described below with reference to the drawings.

２１１図に示すように（１００）面を平面とするｎ形Ｇ
ａＡ　ｓ基板１０上に８ｉ０．膜１１を形成した後フォ
トレジスト法で＜１１０＞方向に中央部分の幅が５μｍ
端面部分の幅が２．５μｍの窓を形成した後Ｂｒとメチ
ルアルコールとの混合溶液を用いてエツチングする。こ
のとき（１ｉ１）Ａ面を両斜面とする■溝が形成される
。■溝はエツチング用マスクに用いたＳ１０．膜１１に
あけた窓に対応して中央部分の深さが３．７μｍ、端面
部分の深さは１．８μｍｖｃなる。又深い溝の長さは２
５０μｍ端面部分の浅い溝の長さは１０μｍ以上５０μ
ｍ以下程度にしておく。次にＳｉｎ、　ｉｌｌ　１を除
去した後第２図、第３図、第４図に示す如（、ｎ形ｋｌ
、、、　Ｇａ０．、　Ａｓクラッド層１２深い溝は溝の
先端から３μｍ程産５ま９この時クラッド層の成長面の
高さは端面近傍の浅い溝領域のクラッド層厚の半分程度
に１に多弁振器長方向において浅い溝内に位置する高さ
となっている。又この結晶成長において深い溝の壁面に
沿った領域にもクラッド層が成長するように制御する必
要が深い溝内部のクラッド層１２に隣接して約０．３μ
ｍ程度の厚さの活性層が形成される。この時活性層の高
さは共振器長方向では端面近傍の浅い溝内のクラッド層
に位置し発振光は堺過する事ができる。211 As shown in Fig. 211, the n-type G whose plane is the (100) plane
8i0. on the aA s substrate 10. After forming the film 11, the width of the central part is 5 μm in the <110> direction using a photoresist method.
After forming a window with a width of 2.5 μm at the end face portion, etching is performed using a mixed solution of Br and methyl alcohol. At this time, (1i1) a groove with both slopes on the A side is formed. ■The groove is the S10. used for the etching mask. The depth of the central portion corresponding to the window formed in the membrane 11 is 3.7 μm, and the depth of the end face portion is 1.8 μmvc. Also, the length of the deep groove is 2
The length of the shallow groove on the 50μm end face is 10μm or more and 50μm.
Keep it below m. Next, after removing Sin and ill 1, the n-type kl
,,, Ga0. The As cladding layer 12 has a deep groove of about 3 μm from the tip of the groove.5 At this time, the height of the growth surface of the cladding layer is about half the thickness of the cladding layer in the shallow groove region near the end face in the longitudinal direction of the multi-wave oscillator. The height is such that it is located within a shallow groove. In addition, in this crystal growth, it is necessary to control the growth of the cladding layer also in the region along the wall surface of the deep trench.
An active layer having a thickness of about 100 m is formed. At this time, the height of the active layer is located at the cladding layer in the shallow groove near the end face in the cavity length direction, allowing the oscillation light to pass through.

は深い溝内部の活性層とはメサ、状の部分でとぎれて成
長する。The active layer inside the deep groove is interrupted by a mesa-shaped part.

長しつぎＫｎ形ｋｌ＠、＠１０ａ６．＠＠　Ａｓキャッ
プ層１５を１μｍ程度成長させる。次に成長面［８ｉ０
．膜１６を形成した後フォトレジスト法で深い溝の領域
上の共振器方向全域（〜２５０μｍ）にゎ之って幅４μ
ｍｏ窓をあけてＺｎを拡散する（　Ｚｎ拡散領域１７）
。Ｚｎ拡散７　Ｃ１７トｕ　ｐ　Ｗ！、ｋｌｏ、４　ｏ
ａ、、　Ａｓクラッド層途中にくるように制御する。次
にＺｎ拡歓部分をともなう成長面側にｐ形オーミックコ
ンタクト１８．ｎ形ＧａＡ　ｓ基板にｎ形オーミックコ
ンタク）１９を形成する。第２図は本発明によって得ら
れた半導体レーザの斜視図であり第３図に深い溝領域の
横断面図％第４図に浅い溝領域の横断面図をそれぞれ示
す。又第５図は２つの■溝の先端を含むように共振器長
方向に切った縦方向の断面図である。Long and continuous Kn type kl@, @10a6. @@ The As cap layer 15 is grown to a thickness of about 1 μm. Next, the growth aspect [8i0
．． After forming the film 16, a photoresist method is used to form a film with a width of 4 μm over the entire region of the deep groove in the cavity direction (~250 μm).
Open the MO window and diffuse Zn (Zn diffusion region 17)
. Zn diffusion 7 C17 to up W! , klo, 4 o
a, Control so that it is located in the middle of the As cladding layer. Next, a p-type ohmic contact 18. An n-type ohmic contact (19) is formed on an n-type GaAs substrate. FIG. 2 is a perspective view of a semiconductor laser obtained according to the present invention, and FIG. 3 is a cross-sectional view of a deep groove region, and FIG. 4 is a cross-sectional view of a shallow groove region. FIG. 5 is a longitudinal sectional view taken along the length of the resonator so as to include the tips of the two grooves.

上記半導体レーザにおりて深因溝内部の活性領域の高さ
は第５図に示すように浅い溝の内部に位置するので発振
光は端面近傍ではｐ形りラッド層内を直進する。クラッ
ド層領域で広がったｆｔ、ａ溝の両端のｎ　−ＧａＡｓ
基板では発振波長０．７８μｍに対して数千１−１から
１〜２万ｃＩＬ−’におよぶ吸収損失をうけるので完全
に吸収される。又一方垂直方向に広が−）次光は第４図
に示したよう（上記ｎ−ＧａＡ１基板と浅い溝領域上部
に形成した非励起領域の活性層に吸収される。従って浅
い溝の部分は光のガイドの役割をはたし横幅１．５μｍ
垂直方向２．１μｍ程度のスポットサイズになり円形に
近い発光源になる。一般にＡｌＧａＡｓ　／　ＧａＡｓ
系ではキャリアの拡散長は３〜４μｍと長すので上記構
造を用いれば基本横モード発振が大光出力発振ＶＣおい
て維持される。本構造によって大光出力発振の光出力と
して５ＭＷ／ｄ以上〜３０ｍＷ以上の光出力が再現性よ
く得られる。In the above semiconductor laser, the height of the active region inside the deep trench is located inside the shallow trench as shown in FIG. 5, so the oscillated light travels straight through the p-shaped rad layer near the end facet. The n-GaAs at both ends of the ft and a grooves expanded in the cladding layer region.
The substrate experiences an absorption loss ranging from several thousand cIL-1 to 10,000 to 20,000 cIL-' for an oscillation wavelength of 0.78 μm, so that it is completely absorbed. On the other hand, as shown in FIG. Acts as a light guide and has a width of 1.5 μm
The spot size in the vertical direction is approximately 2.1 μm, resulting in a nearly circular light source. Generally AlGaAs/GaAs
In the system, the carrier diffusion length is as long as 3 to 4 μm, so if the above structure is used, the fundamental transverse mode oscillation can be maintained in the large optical output oscillation VC. With this structure, an optical output of 5 MW/d or more to 30 mW or more can be obtained with good reproducibility as the optical output of high optical output oscillation.

上記実施例はＡｌＧａＡｓ　／　ＧａＡｓグプルヘテロ
接合結晶材料について説明したが、この材料以外の材料
例えばＩｎＧａＡｓＰ／　ＩｎＧａＰ、　ＩｎＧａＰ／
ＡＡ４１ｎＰ等数多くの結晶材料に適用する事ができる
。Although the above embodiments have been described with respect to the AlGaAs/GaAs group heterojunction crystal material, materials other than this material such as InGaAsP/InGaP, InGaP/
It can be applied to many crystal materials such as AA41nP.

【図面の簡単な説明】[Brief explanation of the drawing]

第１図は本発明の半導体レーザの製作過程でｎ−ＧａＡ
ｓ基板に溝を形成した時の斜視図、第２図は本発明の一
実施例における半導体レーザの斜視図、第３図は第２図
におけるＡ−にの部分で切断し励起領域の断面を示し要
因、ＷＪ４図は第２図におけるＢ　−Ｂ’の部分で切断
し非励起領域の断面を示した図、ａＩ５図は第２図にお
けるｃ　−ｃ’の部分で切断した共振器長方向の断面を
示した図。 図において １０−ｎ形ＧａＡｓ基板％　　１１　８ｉ０．＠、　１
２ｎ形Ａ／Ｇ、４　（Ｊａｍ、＠　Ａ　５クラッド層、
１３　アンドープ”ｏ−Ｉｓ　Ｇａ６４．　Ａｓ活性層
、１４・・Ｉ）形ＡＡ！。、、Ｇａ、＠Ａｓクラッド層
、１５　　ｎ形ｈｌ、、。、　Ｇａ、、、、　Ａｓキャ
ブ層、１６”’　ＳｉＯ＊　ｌｌｌ５　１７　　Ｚｎ拡
歓領域、１８・ｐ形オーミックコンタクト、１９　　・
ｎ形オーミックコンタクト ＃！＋１図 第２図 第３図 ７Figure 1 shows n-GaA in the manufacturing process of the semiconductor laser of the present invention.
FIG. 2 is a perspective view of a semiconductor laser according to an embodiment of the present invention, and FIG. 3 is a cross-section of the excitation region cut at A- in FIG. 2. Figure WJ4 is a cross section of the non-excited region taken along line B-B' in Figure 2, and Figure aI5 is a cross section of the resonator length taken at line c-c' in Figure 2. A diagram showing a cross section. In the figure, 10-n-type GaAs substrate% 11 8i0. @, 1
2n type A/G, 4 (Jam, @ A 5 cladding layer,
13 Undoped "o-Is Ga64. As active layer, 14...I) type AA!..., Ga, @As cladding layer, 15 n-type hl,..., Ga,..., As cab layer, 16"' SiO*llll5 17 Zn expansion region, 18・p-type ohmic contact, 19 ・
N-type ohmic contact #! +1 Figure 2 Figure 3 Figure 7

Claims (1)

【特許請求の範囲】[Claims] 発振波長よりもバンドギャップの狭い半導体に共振器長
方向に内反射面近傍では浅く中央部分では深い溝を形成
し、この半導体上に前記内反射面近傍の浅い溝を埋込む
第１のクラッド層、これに隣接した活性層、前記深い溝
を埋込む第２のクラッド層、キャップ層を積層して多層
構造を形成し、前記深い溝における活性層の深さ方向の
位置が前記内反射面近傍の浅い溝の内部にあると共に前
記深い溝における活性層と前記浅い溝における活性層と
が同一平面になく、さらに、前記深い壽の活性層上のキ
ャップ層に電流注入領域を設けた事を特徴とする半導体
レーザ。A first cladding layer in which a groove is formed in a semiconductor having a band gap narrower than the oscillation wavelength, shallow in the vicinity of the internal reflection surface and deep in the central portion in the cavity length direction, and the shallow groove in the vicinity of the internal reflection surface is buried on the semiconductor. , an active layer adjacent to this, a second cladding layer that fills the deep groove, and a cap layer are stacked to form a multilayer structure, and the position of the active layer in the depth direction in the deep groove is near the internal reflection surface. The active layer in the deep groove and the active layer in the shallow groove are not on the same plane, and further, a current injection region is provided in the cap layer on the active layer in the deep groove. semiconductor laser.
JP7937282A 1982-05-12 1982-05-12 Semiconductor laser Pending JPS58197787A (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
JP7937282A JPS58197787A (en) 1982-05-12 1982-05-12 Semiconductor laser

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
JP7937282A JPS58197787A (en) 1982-05-12 1982-05-12 Semiconductor laser

Publications (1)

Publication Number Publication Date
JPS58197787A true JPS58197787A (en) 1983-11-17

Family

ID=13688037

Family Applications (1)

Application Number Title Priority Date Filing Date
JP7937282A Pending JPS58197787A (en) 1982-05-12 1982-05-12 Semiconductor laser

Country Status (1)

Country Link
JP (1) JPS58197787A (en)

Cited By (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS58207691A (en) * 1982-05-28 1983-12-03 Sharp Corp Semiconductor laser element
JPS61121381A (en) * 1984-11-19 1986-06-09 Hitachi Ltd Semiconductor laser device
EP0189296A2 (en) * 1985-01-23 1986-07-30 Sharp Kabushiki Kaisha A semiconductor laser device
US4679200A (en) * 1984-01-17 1987-07-07 Sharp Kabushiki Kaisha Semiconductor laser
EP0291936A2 (en) * 1987-05-18 1988-11-23 Kabushiki Kaisha Toshiba Semiconductor Laser
US4890292A (en) * 1986-09-02 1989-12-26 Mitsubishi Denki Kabushiki Kaisha Semiconductor laser device

Cited By (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS58207691A (en) * 1982-05-28 1983-12-03 Sharp Corp Semiconductor laser element
JPS6139758B2 (en) * 1982-05-28 1986-09-05 Sharp Kk
US4679200A (en) * 1984-01-17 1987-07-07 Sharp Kabushiki Kaisha Semiconductor laser
JPS61121381A (en) * 1984-11-19 1986-06-09 Hitachi Ltd Semiconductor laser device
EP0189296A2 (en) * 1985-01-23 1986-07-30 Sharp Kabushiki Kaisha A semiconductor laser device
US4890292A (en) * 1986-09-02 1989-12-26 Mitsubishi Denki Kabushiki Kaisha Semiconductor laser device
US4983541A (en) * 1986-09-02 1991-01-08 Mitsubishi Denki Kabushiki Kaisha Semiconductor laser device fabrication
EP0291936A2 (en) * 1987-05-18 1988-11-23 Kabushiki Kaisha Toshiba Semiconductor Laser

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