JP2953326B2 - Method of manufacturing gallium nitride based compound semiconductor laser device - Google Patents
Method of manufacturing gallium nitride based compound semiconductor laser deviceInfo
- Publication number
- JP2953326B2 JP2953326B2 JP29543394A JP29543394A JP2953326B2 JP 2953326 B2 JP2953326 B2 JP 2953326B2 JP 29543394 A JP29543394 A JP 29543394A JP 29543394 A JP29543394 A JP 29543394A JP 2953326 B2 JP2953326 B2 JP 2953326B2
- Authority
- JP
- Japan
- Prior art keywords
- gallium nitride
- based compound
- compound semiconductor
- plane
- sapphire substrate
- 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
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Description
【０００１】[0001]
【産業上の利用分野】本発明は窒化ガリウム系化合物半
導体（ＩｎXＡｌYＧａ1-X-YＮ、0≦X、0≦Y、X＋Y≦
１）よりなるレーザ素子の製造方法に係り、特にサファ
イア基板のＣ面上に窒化ガリウム系化合物半導体がレー
ザ素子の構造となるように積層されたウェーハから半導
体素子の光共振面を形成する方法に関する。The present invention relates to a gallium nitride compound semiconductor (In X Al Y Ga 1- XY N, 0 ≦ X, 0 ≦ Y, X + Y ≦
More particularly, the present invention relates to a method for forming an optical resonance surface of a semiconductor device from a wafer in which a gallium nitride-based compound semiconductor is laminated on a C-plane of a sapphire substrate so as to have a structure of the laser device. .
【０００２】[0002]
【従来の技術】青色〜紫外域にレーザ発振し得る半導体
材料の一つに窒化ガリウム系化合物半導体（ＩｎXＡｌY
Ｇａ1-X-YＮ、０≦X、０≦Y、X＋Y≦１）が知られてい
る。また最近、窒化ガリウム系化合物半導体よりなるダ
ブルへテロ構造の発光ダイオード、が実用化されたこと
により、レーザダイオードが急に注目されるようになっ
た。2. Description of the Related Art One of semiconductor materials capable of laser oscillation in the blue to ultraviolet region is a gallium nitride-based compound semiconductor (In X Al Y).
Ga 1 -XYN , 0 ≦ X, 0 ≦ Y, X + Y ≦ 1) are known. Further, recently, a laser diode having a double heterostructure made of a gallium nitride-based compound semiconductor has been put to practical use.
【０００３】窒化ガリウム系化合物半導体を用いたレー
ザ素子は従来より数々の構造が提案されている。例えば
特開平６−２８３８２５号公報ではＳｉドープｎ型Ａｌ
ＧａＮ／Ｓｉドープｎ型ＧａＮ／ＭｇドープＡｌＧａＮ
ダブルへテロ構造のレーザダイオードが開示されてお
り、またＵＳＰ５，１４６，４６５にはＡｌＧａＮを活
性層として、ＡｌＧａＮの多層膜で光共振面を形成した
レーザ素子が開示されている。[0003] Numerous structures have been proposed for laser devices using gallium nitride-based compound semiconductors. For example, Japanese Patent Application Laid-Open No. 6-283825 discloses a Si-doped n-type Al
GaN / Si doped n-type GaN / Mg doped AlGaN
A laser diode having a double hetero structure is disclosed, and US Pat. No. 5,146,465 discloses a laser device in which an optical resonance surface is formed of an AlGaN multilayer film using AlGaN as an active layer.
【０００４】[0004]
【発明が解決しようとする課題】しかしながら、窒化ガ
リウム系化合物半導体のレーザ素子は未だ実現されてい
ない。その理由は数々あるが、その一つにレーザ素子で
不可欠な光共振面の形成が困難であるという問題があ
る。However, a gallium nitride based compound semiconductor laser device has not yet been realized. Although there are various reasons, one of them is a problem that it is difficult to form an optical resonance surface indispensable in a laser device.
【０００５】一般に窒化ガリウム系化合物半導体はサフ
ァイア基板の上に成長されることが多い。サファイアは
六方晶系という結晶の性質上、劈開性を有していない。
さらに窒化ガリウム系化合物半導体も同じく六方晶系で
あるので劈開性を有していない。一方、赤外、赤色半導
体レーザ素子に使用されるＧａＡｓ系の材料は立方晶系
であって劈開性を有しているため、半導体レーザの共振
面は半導体結晶の劈開面が使用される。In general, a gallium nitride compound semiconductor is often grown on a sapphire substrate. Sapphire does not have cleavage properties due to its hexagonal crystal nature.
Further, gallium nitride-based compound semiconductors are also hexagonal and do not have cleavage. On the other hand, since the GaAs-based material used for the infrared and red semiconductor laser elements is cubic and has cleavage, the cleavage plane of the semiconductor crystal is used as the resonance plane of the semiconductor laser.
【０００６】半導体レーザを実現する上で光共振面を形
成することは非常に重要である。ところが前記のように
窒化ガリウム系化合物半導体は劈開性を有していないの
で、劈開面を光共振面とすることができないという欠点
がある。従来、レーザ素子となる窒化ガリウム系化合物
半導体の積層構造は多く提案されているが、実際の光共
振面の形成方法については知られていないのが実状であ
る。そこで、本発明はこのような事情を鑑みて成された
ものであって、その目的とするところは、サファイア基
板の上に窒化ガリウム系化合物半導体がレーザ素子とな
る構造で積層されたウェーハから半導体層に光共振面を
実現できるレーザ素子の製造方法を提供するにある。To realize a semiconductor laser, it is very important to form an optical resonance surface. However, since the gallium nitride-based compound semiconductor has no cleavage property as described above, there is a disadvantage that the cleavage plane cannot be an optical resonance plane. Conventionally, many laminated structures of gallium nitride-based compound semiconductors to be used as laser elements have been proposed, but the actual method of forming an optical resonance surface is not known. Accordingly, the present invention has been made in view of such circumstances, and an object of the present invention is to provide a semiconductor device having a structure in which a gallium nitride-based compound semiconductor is stacked on a sapphire substrate in a structure to be a laser device. It is an object of the present invention to provide a method for manufacturing a laser device capable of realizing an optical resonance surface in a layer.
【０００７】[0007]
【課題を解決するための手段】我々は特定の面方位のサ
ファイア基板の表面に窒化ガリウム系化合物半導体を積
層した後、そのサファイア基板を特定の面方位で割るこ
とによって、窒化ガリウム系化合物半導体層の光共振面
を作製できることを新たに見いだし本発明を成すに至っ
た。即ち、本発明の窒化ガリウム系化合物半導体レーザ
素子の製造方法は、サファイア基板の（０００１）面の
表面に窒化ガリウム系化合物半導体をレーザ素子の構造
に積層した後、そのサファイア基板を数１、数２、数
３、数４、数５、数６面（以下特に記載のない限り、前
記六種類の面方位をまとめてＭ面という。）の内のいず
れかの面方位でかつその分割位置でのサファイア基板の
厚さを１５０μｍ以下にして割ることにより半導体レー
ザ素子の光共振面を作製することを特徴とする。Means for Solving the Problems We deposit a gallium nitride-based compound semiconductor on the surface of a sapphire substrate having a specific plane orientation, and then divide the sapphire substrate by the specific plane orientation to obtain a gallium nitride-based compound semiconductor layer. The present inventors have newly found that an optical resonance surface can be manufactured, and have accomplished the present invention. That is, according to the method of manufacturing a gallium nitride-based compound semiconductor laser device of the present invention, after a gallium nitride-based compound semiconductor is laminated on the surface of the (0001) plane of the sapphire substrate in the structure of the laser device, In any one of the 2, 3, 4, 5, and 6 planes (the above six plane orientations are collectively referred to as an M plane unless otherwise specified) and at the division position thereof. The optical resonance surface of the semiconductor laser device is manufactured by dividing the thickness of the sapphire substrate to 150 μm or less.
【０００８】図１にサファイア単結晶の面方位を表すユ
ニットセル図を示す。本発明ではこのユニットセル図の
（０００１）面（以下、この面をＣ面という。）に窒化
ガリウム系化合物半導体を積層する。サファイアのＣ面
に窒化ガリウム系化合物半導体をＣ軸方向に配向させて
積層する。窒化ガリウム系化合物半導体は、例えばＨＤ
ＶＰＥ（ハイドライド気相成長法）、ＭＯＶＰＥ（有機
金属気相成長法）、ＭＢＥ（分子線気相成長法）等の気
相成長法により成長させることができる。また、サファ
イア基板のＣ面とは（０００１）面に完全に一致してい
ることはいうまでもなく、（０００１）面よりおよそ±
１０゜以内の範囲でオフ角を有するＣ面であってもよ
い。FIG. 1 is a unit cell diagram showing the plane orientation of a sapphire single crystal. In the present invention, a gallium nitride-based compound semiconductor is laminated on a (0001) plane (hereinafter, this plane is referred to as a C plane) of the unit cell diagram. A gallium nitride-based compound semiconductor is laminated on the C-plane of sapphire with its orientation oriented in the C-axis direction. Gallium nitride-based compound semiconductors include, for example, HD
It can be grown by a vapor phase growth method such as VPE (hydride vapor phase epitaxy), MOVPE (metal organic vapor phase epitaxy), or MBE (molecular beam vapor phase epitaxy). Also, it goes without saying that the C plane of the sapphire substrate completely coincides with the (0001) plane, and is approximately ±
A C-plane having an off angle within a range of 10 ° or less may be used.
【０００９】レーザ素子の構造とするには、基本的にダ
ブルへテロ構造を達成すればよく、例えばＩｎＧａＮ／
ＡｌＧａＮ（活性層／クラッド層）、ＩｎＧａＮ／Ｇａ
Ｎ、ＡｌＧａＮ／ＡｌＧａＮ等のヘテロ接合でダブルへ
テロ構造を達成することができる。好適には活性層はノ
ンドープｎ型ＩｎXＡｌYＧａ1-X-YＮ（０＜X、０≦Y、X
＋Y＜１）、またはｎ型ドーパントおよび／またはｐ型
ドーパントをドープしたｎ型ＩｎXＡｌYＧａ1-X-YＮ
（０＜X、０≦Y、X＋Y＜１）として、活性層を互いに導
電型が異なり活性層よりもバンドギャップの大きい窒化
ガリウム系化合物半導体で挟んだダブルへテロ構造とす
る。活性層を少なくともインジウムとガリウムとを含む
窒化ガリウム系化合物半導体とすることにより、ＩｎＧ
ａＮのバンド間発光のみでレーザ発光波長を紫〜赤色ま
で変化させることができる。さらに、活性層はｎ型であ
る方が結晶欠陥の少ない半導体層が得られるのでレーザ
の信頼性が向上する。さらにまたＳｉ、Ｇｅ、Ｓ等のｎ
型ドーパント、Ｚｎ、Ｍｇ、Ｃｄ等のｐ型ドーパントを
ドープするとＩｎＧａＮのバンド間発光の他に、発光中
心ができるので、発振波長の補正をすることも可能であ
る。In order to obtain the structure of the laser element, it is basically sufficient to achieve a double hetero structure.
AlGaN (active layer / cladding layer), InGaN / Ga
A double heterostructure can be achieved with a heterojunction such as N or AlGaN / AlGaN. Preferably, the active layer is a non-doped n-type In x Al Y Ga 1 -XYN (0 <X, 0 ≦ Y, X
+ Y <1), or n-type In x Al Y Ga 1-XY N doped with an n-type dopant and / or a p-type dopant
Assuming that (0 <X, 0 ≦ Y, X + Y <1), the active layer has a double hetero structure sandwiched between gallium nitride-based compound semiconductors having different conductivity types and a larger band gap than the active layer. By forming the active layer from a gallium nitride-based compound semiconductor containing at least indium and gallium, InG
The laser emission wavelength can be changed from purple to red only by the interband emission of aN. Further, when the active layer is of the n-type, a semiconductor layer having less crystal defects can be obtained, so that the reliability of the laser is improved. Furthermore, n of Si, Ge, S, etc.
When a p-type dopant such as Zn, Mg, or Cd is doped with a p-type dopant, an emission center is formed in addition to the inter-band emission of InGaN, so that the oscillation wavelength can be corrected.
【００１０】例えばレーザ素子の構造には、利得導波型
ストライプ型レーザとしては、電極ストライプ型、メサ
ストライプ型、ヘテロアイソレーション型等を挙げるこ
とができ、またその他、作りつけ導波機構をもつストラ
イプ型レーザとして、埋め込みヘテロ型、ＣＳＰ型、リ
ブガイド型等を挙げることができる。For example, in the structure of the laser device, the gain-guided stripe type laser can be an electrode stripe type, a mesa stripe type, a hetero-isolation type, etc., and also has a built-in waveguide mechanism. Examples of the stripe type laser include a buried hetero type, a CSP type, a rib guide type, and the like.
【００１１】次に、気相成長法によりサファイア基板の
Ｃ面に窒化ガリウム系化合物半導体を積層した後、最上
層のｐ型窒化ガリウム系化合物半導体層に正電極を形成
する。図２に本発明の一方法による窒化ガリウム系化合
物半導体レーザ素子の斜視図を示す。これは基本的には
メサストライプ型のレーザ素子の構造を示しており、サ
ファイア基板１のＣ面上にｎ型の窒化ガリウム系化合物
半導体よりなる第一のクラッド層２とｎ型の窒化ガリウ
ム系化合物半導体よりなる活性層３と、ｐ型の窒化ガリ
ウム系化合物半導体よりなる第二のクラッド層４とを積
層してダブルへテロ構造とし、第二のクラッド層４の表
面にストライプ状の正電極１２と、第一のクラッド層２
の表面に同じくストライプ状の負電極１１を形成してい
る。このように、例えばストライプ型レーザを実現する
には導波路として正電極を数μｍ〜２０μｍ程度の幅で
形成することにより、ストライプに沿って発振を起こす
ことができる。図２では活性層３のレーザ発振領域をハ
ッチングして示している。ここで、正電極を形成する場
合に注意することは、後でサファイア基板をＭ面で割っ
た際、その分割面の窒化ガリウム系化合物半導体層を光
共振面とするので、窒化ガリウム系化合物半導体の分割
面に対してストライプが垂直となるように電極を形成す
る必要がある。なお、前記のようにサファイアをＭ面で
割った場合、窒化ガリウム系化合物半導体の光共振面は
六方晶系のNext, after a gallium nitride-based compound semiconductor is laminated on the C-plane of the sapphire substrate by vapor phase growth, a positive electrode is formed on the uppermost p-type gallium nitride-based compound semiconductor layer. FIG. 2 is a perspective view of a gallium nitride based compound semiconductor laser device according to one method of the present invention. This basically shows the structure of a mesa-stripe type laser element. A first cladding layer 2 made of an n-type gallium nitride-based compound semiconductor and an n-type gallium nitride-based compound semiconductor are formed on a C-plane of a sapphire substrate 1. An active layer 3 made of a compound semiconductor and a second clad layer 4 made of a p-type gallium nitride-based compound semiconductor are laminated to form a double heterostructure, and a stripe-shaped positive electrode is formed on the surface of the second clad layer 4. 12 and the first cladding layer 2
A negative electrode 11 in the form of a stripe is also formed on the surface of. Thus, for example, in order to realize a stripe type laser, oscillation can be generated along the stripe by forming a positive electrode as a waveguide with a width of about several μm to 20 μm. In FIG. 2, the laser oscillation region of the active layer 3 is hatched. Here, when forming the positive electrode, it should be noted that when the sapphire substrate is later divided by the M plane, the gallium nitride-based compound semiconductor layer on the divided surface is used as an optical resonance surface. It is necessary to form the electrodes so that the stripes are perpendicular to the divided plane. When sapphire is divided by the M-plane as described above, the optical resonance surface of the gallium nitride-based compound semiconductor has a hexagonal system.
【数７】 （１１０） 面となることが多い。## EQU7 ## In many cases, the (110) plane is used.
【００１２】次に本発明の最も重要な点である光共振面
の形成方法について述べる。本発明ではサファイアのＣ
面上に窒化ガリウム系化合物半導体を積層したウェーハ
を、サファイア基板のＭ面の内のいずれかで割って、窒
化ガリウム系化合物半導体の光共振面を形成する。例え
ば図１において、例えば斜線部で示すサファイア基板の
数３面で割った窒化ガリウム系化合物半導体層と、数３
面と対向する同じく斜線部で示す数６面で割った窒化ガ
リウム系化合物半導体層とで光共振面を形成することが
できる。なおこの共振面は前記のように六方晶系の数７
面となることが多い。Next, a method of forming an optical resonance surface, which is the most important point of the present invention, will be described. In the present invention, sapphire C
The wafer on which the gallium nitride-based compound semiconductor is laminated is divided by any one of the M planes of the sapphire substrate to form an optical resonance surface of the gallium nitride-based compound semiconductor. For example, in FIG. 1, for example, a gallium nitride-based compound semiconductor layer divided by three surfaces of a sapphire substrate indicated by hatched portions,
The optical resonance surface can be formed by the gallium nitride-based compound semiconductor layer divided by the surface of the gallium nitride-based compound semiconductor, which is also indicated by the hatched portion facing the surface. Note that this resonance surface has a hexagonal number of 7 as described above.
Often a surface.
【００１３】ウェーハを割る手段として例えばスクライ
バー、またはダイサーを用いることができる。スクライ
バーを用いた場合、窒化ガリウム系化合物半導体層と対
向するサファイア基板をスクライブする前に基板の厚さ
を１５０μｍ以下、さらに好ましくは１００μｍ以下の
厚さに研磨して薄くすることが望ましい。基板を１５０
μｍ以下に研磨して薄くすることにより、Ｍ面からウェ
ーハを割る際にスクライブラインより真っ直ぐに割れ易
くなり、割れた窒化ガリウム系化合物半導体層面を光共
振面とすることが容易になる。一方、ダイサーで割る場
合には、同じく窒化ガリウム系化合物半導体層と対向す
るサファイア基板側をハーフカットした後、ウェーハを
圧し割ることにより光共振面を形成できる。さらに、ス
クライバーとダイサーとを組み合わせてウェーハを割る
ことも可能である。図３は本発明の一工程で得られるウ
ェーハの模式的な断面図を示している。これはサファイ
ア基板の表面をまずダイサーでハーフカットして、その
ダイシング溝の跡をスクライブした時のウェーハの状態
を示している。サファイア基板に形成された広い溝がダ
イサーでのハーフカットを示しており、ダイサー溝の中
心に入れられた小さな溝がスクライバーによる溝を示し
ている。この図に示すようにダイサーによるハーフカッ
ト、スクライバーでウェーハを割る際には前記のように
サファイア基板の厚さを１５０μｍ以下にすることによ
り、窒化ガリウム系化合物半導体層に光共振面を形成す
ることが容易となる傾向にある。なお、ウェーハを割る
には前記スクライブ、ダイシングの後、ローラー等でウ
ェーハを圧し割ることによって簡単に割ることができ
る。As a means for breaking the wafer, for example, a scriber or a dicer can be used. When a scriber is used, it is desirable to reduce the thickness of the sapphire substrate by polishing to a thickness of 150 μm or less, more preferably 100 μm or less, before scribing the sapphire substrate facing the gallium nitride-based compound semiconductor layer. 150 substrates
When the wafer is polished to a thickness of not more than μm and thinned, the wafer can be easily broken straight from the scribe line when the wafer is split from the M plane, and the broken gallium nitride-based compound semiconductor layer can easily be used as an optical resonance surface. On the other hand, in the case of dividing by a dicer, an optical resonance surface can be formed by half-cutting the sapphire substrate side facing the gallium nitride-based compound semiconductor layer and then pressing and dividing the wafer. Further, it is also possible to crack a wafer by combining a scriber and a dicer. FIG. 3 is a schematic sectional view of a wafer obtained in one step of the present invention. This shows the state of the wafer when the surface of the sapphire substrate is first half-cut with a dicer and the trace of the dicing groove is scribed. A wide groove formed on the sapphire substrate indicates a half cut by the dicer, and a small groove inserted in the center of the dicer groove indicates a groove formed by a scriber. As shown in this figure, when the wafer is cut with a dicer, the optical resonance surface is formed on the gallium nitride based compound semiconductor layer by making the thickness of the sapphire substrate 150 μm or less as described above. Tends to be easier. The wafer can be easily split by pressing and splitting the wafer with a roller or the like after scribing and dicing.
【００１４】[0014]
【作用】図１を元に本発明の方法の作用を説明する。サ
ファイア単結晶は窒化ガリウム系化合物半導体と異なり
結晶性が非常に良く、図１に示すようにほぼ正確な六方
晶系を有している。一方、窒化ガリウム系化合物半導体
は六方晶系といえどもサファイア基板の上に必ずしも基
板と一致した結晶形で積層されるわけではない。しかし
サファイアの結晶系が安定しているならば、安定したサ
ファイアの方でウェーハを割ってやることにより、窒化
ガリウム系化合物半導体を安定して割れ易くすることが
可能となり、あたかも窒化ガリウム系化合物半導体で劈
開面を形成したかのような状態にすることができるので
ある。特に、図１の斜線部で示すようにサファイアのＭ
面は必ず対向するもう一方のＭ面を有しているため、そ
れらのＭ面でウェーハを割ることによって、窒化ガリウ
ム系化合物半導体層に対向する光共振面を形成できる。The operation of the method of the present invention will be described with reference to FIG. A sapphire single crystal has very good crystallinity unlike a gallium nitride-based compound semiconductor, and has a substantially accurate hexagonal system as shown in FIG. On the other hand, a gallium nitride-based compound semiconductor is not always laminated on a sapphire substrate in a crystal form consistent with the substrate, even though it is hexagonal. However, if the crystal system of sapphire is stable, it is possible to break the gallium nitride compound semiconductor easily and easily by cracking the wafer with the stable sapphire, as if it were a gallium nitride compound semiconductor. Thus, it is possible to make a state as if a cleavage plane was formed. In particular, as shown by the hatched portion in FIG.
Since the surfaces always have the other opposing M-plane, the optical resonance surface opposing the gallium nitride-based compound semiconductor layer can be formed by dividing the wafer by these M-planes.
【００１５】さらに、サファイア単結晶のＭ面は、他の
サファイアの面方位、例えばＣ面、Ａ面（数７面）等に
比べて、割れやすい性質がある。一方、サファイアの上
にレーザ素子の構造に積層される窒化ガリウム系化合物
半導体層の厚さはせいぜい１０μｍ以下でしかなく、こ
れに対しサファイア基板は１０倍以上の厚さを有してい
る。このため、割り易いＭ面でサファイア基板を割る
と、サファイア基板に積層された膜厚の薄い窒化ガリウ
ム系化合物半導体層が、サファイア基板のＭ面につられ
て割れ、その割れた窒化ガリウム系化合物半導体層面が
劈開面のような状態となり光共振面となる。Further, the M-plane of the sapphire single crystal has a property that it is more easily broken than the plane orientation of other sapphire, for example, the C-plane and the A-plane (Equation 7). On the other hand, the thickness of the gallium nitride-based compound semiconductor layer laminated on the structure of the laser element on sapphire is at most 10 μm or less, whereas the thickness of the sapphire substrate is 10 times or more. For this reason, when the sapphire substrate is divided at the M-plane which is easy to split, the thin gallium nitride-based compound semiconductor layer laminated on the sapphire substrate is broken along the M-plane of the sapphire substrate, and the cracked gallium nitride-based compound semiconductor is broken. The layer surface becomes like a cleavage plane and becomes an optical resonance plane.
【００１６】[0016]
【実施例】図４および図５を元に本発明の方法を詳説す
る。なお、図４は本発明の一方法により得られたレーザ
素子をＭ面と平行な方向で切断した際の模式断面図を示
しており、図５はウェーハの窒化ガリウム系化合物半導
体層に正電極を形成した際の平面図を示している。DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The method of the present invention will be described in detail with reference to FIGS. FIG. 4 is a schematic cross-sectional view of the laser device obtained by one method of the present invention when cut in a direction parallel to the M-plane. FIG. 5 shows a positive electrode on the gallium nitride-based compound semiconductor layer of the wafer. FIG. 3 shows a plan view when forming a pattern.
【００１７】Ｃ面を主面とする厚さ５００μｍのサファ
イア基板３０の表面にＭＯＶＰＥ法を用いて窒化ガリウ
ム系化合物半導体を積層した。なおサファイア基板はＡ
面（数７面）がオリエンテーションフラットされた面を
用いた。積層順はサファイア基板表面から順にＧａＮよ
りなるバッファ層３１が２００オングストローム、Ｓｉ
ドープｎ型ＧａＮよりなるｎ型コンタクト層３２が４μ
ｍ、Ｓｉドープｎ型ＡｌＧａＮよりなるｎ型クラッド層
３３が０．１μｍ、ノンドープｎ型ＩｎＧａＮ層よりな
る活性層３４が５００オングストローム、Ｍｇドープｐ
型ＡｌＧａＮ層よりなるｐ型クラッド層３５が０．１μ
ｍ、Ｍｇドープｐ型ＧａＮ層よりなるｐ型コンタクト層
３６が０．５μｍの膜厚で成長した。A gallium nitride-based compound semiconductor was laminated on the surface of a sapphire substrate 30 having a thickness of 500 μm and having the C-plane as a main surface by MOVPE. The sapphire substrate is A
A plane (Equation 7) having an orientation flat was used. The lamination order is such that the buffer layer 31 made of GaN is 200 angstrom, Si
The n-type contact layer 32 made of doped n-type GaN has a thickness of 4 μm.
m, n-type cladding layer 33 made of Si-doped n-type AlGaN is 0.1 μm, active layer 34 made of non-doped n-type InGaN layer is 500 Å, Mg-doped p-type.
The p-type cladding layer 35 composed of the AlGaN layer has a thickness of 0.1 μm.
A p-type contact layer 36 of m, Mg-doped p-type GaN layer was grown to a thickness of 0.5 μm.
【００１８】次に最上層であるｐ型コンタクト層３６の
表面に所定のストライプ形状のマスクを形成し、ｐ型コ
ンタクト層３６、ｐ型クラッド層３５、活性層３４、ｎ
型クラッド層３３の一部をエッチングして取り除き負電
極１１を形成すべきｎ型コンタクト層３２を露出させ
た。Next, a mask having a predetermined stripe shape is formed on the surface of the uppermost p-type contact layer 36, and the p-type contact layer 36, the p-type cladding layer 35, the active layer 34, and the n-type
A part of the mold clad layer 33 was removed by etching to expose the n-type contact layer 32 where the negative electrode 11 was to be formed.
【００１９】エッチング後、マスクを除去し、再度所定
の形状のマスクを形成して、ｎ型コンタクト層３２に２
０μｍの幅で負電極１１、ｐ型コンタクト層３６に２μ
ｍの幅で正電極１２をそれぞれ形成した。正電極１２形
成時のウェーハの表面を示す平面図を図５に示してい
る。正電極１２、負電極１１をウェーハのオリエンテー
ションフラット面、Ａ面に平行な方向で形成すると、図
５の破線に示すようにＡ面に垂直な方向でウェーハを割
ると、自動的にＭ面からウェーハを割ることができる。After the etching, the mask is removed, and a mask having a predetermined shape is formed again.
The negative electrode 11 has a width of 0 μm and the p-type contact layer 36 has a width of 2 μm.
The positive electrode 12 was formed with a width of m. FIG. 5 is a plan view showing the surface of the wafer when the positive electrode 12 is formed. When the positive electrode 12 and the negative electrode 11 are formed in a direction parallel to the orientation flat surface of the wafer and the A surface, when the wafer is divided in a direction perpendicular to the A surface as shown by a broken line in FIG. The wafer can be broken.
【００２０】次に、窒化ガリウム系化合物半導体層を形
成していない方のサファイア基板面を研磨して基板の厚
さを９０μｍにした。研磨後、ウェーハをスクライバー
にセットして、研磨したサファイア基板表面をスクライ
ブした。スクライブ方向はＡ面に平行な方向と、図５の
破線に示すようにＡ面に垂直な方向としてスクライブし
た。Next, the surface of the sapphire substrate on which the gallium nitride-based compound semiconductor layer was not formed was polished to a thickness of 90 μm. After polishing, the wafer was set on a scriber, and the polished sapphire substrate surface was scribed. The scribing direction was a direction parallel to the plane A and a direction perpendicular to the plane A as shown by the broken line in FIG.
【００２１】スクライブ後、ウェーハをローラーで圧し
割りウェーハを７００μｍ角のチップに分割した。この
チップは図４に示すような構造を有しており、Ａ面に垂
直な方向で割った面がレーザ素子の光共振面とされてい
る。次に分割されたチップをヒートシンクに設置し、そ
れぞれの電極をワイヤーボンドした後、液体窒素温度で
レーザ発振を試みたところ、しきい値電流密度１．５ｋ
Ａ／cm2で発振波長３９０ｎｍのレーザ発振が確認され
た。After scribing, the wafer was pressed with a roller to split the wafer into 700 μm square chips. This chip has a structure as shown in FIG. 4, and a plane divided by a direction perpendicular to the plane A is an optical resonance plane of the laser element. Next, the divided chips were placed on a heat sink, and after wire bonding each electrode, laser oscillation was attempted at liquid nitrogen temperature.
Laser oscillation having an oscillation wavelength of 390 nm at A / cm 2 was confirmed.
【００２２】[0022]
【発明の効果】以上説明したように、本発明では初めて
具体的な方法で光共振面の形成方法を示しているので、
劈開性のないサファイア基板上に積層した窒化ガリウム
系化合物半導体層より劈開面と同様の光共振面が得られ
てレーザ発振が可能となる。このため同一半導体材料を
用いて紫外〜赤色までの半導体レーザが実現可能となり
その産業上の利用価値は非常に大きい。As described above, in the present invention, for the first time, a method for forming an optical resonance surface is shown by a specific method.
An optical resonance surface similar to the cleavage plane is obtained from the gallium nitride-based compound semiconductor layer laminated on the sapphire substrate having no cleavage, and laser oscillation becomes possible. For this reason, semiconductor lasers from ultraviolet to red can be realized using the same semiconductor material, and the industrial use value thereof is very large.
【図１】 サファイア単結晶の面方位を表すユニットセ
ル図。FIG. 1 is a unit cell diagram showing a plane orientation of a sapphire single crystal.
【図２】 本発明の一実施例によるレーザ素子の斜視
図。FIG. 2 is a perspective view of a laser device according to one embodiment of the present invention.
【図３】 本発明の方法の一工程で得られるウェーハの
模式断面図。FIG. 3 is a schematic sectional view of a wafer obtained in one step of the method of the present invention.
【図４】 本発明の一実施例によるレーザ素子をＭ面と
平行な方向で切断した際の模式断面図。FIG. 4 is a schematic cross-sectional view when the laser device according to one embodiment of the present invention is cut in a direction parallel to the M-plane.
【図５】 正電極を形成した際のウェーハの表面を示す
平面図。FIG. 5 is a plan view showing a surface of a wafer when a positive electrode is formed.
１、３０・・・・サファイア基板 ２・・・・第一のクラッド層 ３、３４・・・・活性層 ４・・・・第二のクラッド層 ３１・・・・バッファ層３１ ３２・・・・ｎ型コンタクト層３２ ３３・・・・ｎ型クラッド層 ３５・・・・ｐ型クラッド層３５ ３６・・・・ｐ型コンタクト層 １１・・・・負電極 １２・・・・正電極 1, 30 sapphire substrate 2 first cladding layer 3, 34 active layer 4 second cladding layer 31 buffer layer 31 32 · N-type contact layer 32 33 ··· n-type cladding layer 35 ··· p-type cladding layer 35 36 ··· p-type contact layer 11 ··· negative electrode 12 ··· positive electrode
Claims (1)
に窒化ガリウム系化合物半導体をレーザ素子の構造に積
層した後、そのサファイア基板を 【数１】 （１００） 【数２】 （１００） 【数３】 （０１０） 【数４】 （１００） 【数５】 （０１０） 【数６】 （０１０） 面のうちのいずれかの面方位で、かつその分割位置での
サファイア基板の厚さを１５０μｍ以下にして割ること
により半導体レーザ素子の光共振面を作製することを特
徴とする窒化ガリウム系化合物半導体レーザ素子の製造
方法。After laminating a gallium nitride-based compound semiconductor on the surface of a (0001) plane of a sapphire substrate in a structure of a laser device, the sapphire substrate is expressed by the following formula: (010) (4) (100) (5) (010) (6) The thickness of the sapphire substrate at any one of the plane orientations and at the division position is set to 150 μm. A method for manufacturing a gallium nitride-based compound semiconductor laser device, characterized in that an optical resonance surface of the semiconductor laser device is manufactured by dividing as follows.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP29543394A JP2953326B2 (en) | 1994-11-30 | 1994-11-30 | Method of manufacturing gallium nitride based compound semiconductor laser device |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP29543394A JP2953326B2 (en) | 1994-11-30 | 1994-11-30 | Method of manufacturing gallium nitride based compound semiconductor laser device |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPH08153931A JPH08153931A (en) | 1996-06-11 |
| JP2953326B2 true JP2953326B2 (en) | 1999-09-27 |
Family
ID=17820542
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| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP29543394A Expired - Fee Related JP2953326B2 (en) | 1994-11-30 | 1994-11-30 | Method of manufacturing gallium nitride based compound semiconductor laser device |
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| Country | Link |
|---|---|
| JP (1) | JP2953326B2 (en) |
Families Citing this family (17)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP3557011B2 (en) | 1995-03-30 | 2004-08-25 | 株式会社東芝 | Semiconductor light emitting device and manufacturing method thereof |
| JPH08316582A (en) * | 1995-05-19 | 1996-11-29 | Nec Corp | Semiconductor laser |
| US6377596B1 (en) | 1995-09-18 | 2002-04-23 | Hitachi, Ltd. | Semiconductor materials, methods for fabricating semiconductor materials, and semiconductor devices |
| JP3537977B2 (en) * | 1996-12-27 | 2004-06-14 | 日亜化学工業株式会社 | Method of manufacturing nitride semiconductor laser device |
| US6608327B1 (en) | 1998-02-27 | 2003-08-19 | North Carolina State University | Gallium nitride semiconductor structure including laterally offset patterned layers |
| US6051849A (en) | 1998-02-27 | 2000-04-18 | North Carolina State University | Gallium nitride semiconductor structures including a lateral gallium nitride layer that extends from an underlying gallium nitride layer |
| US6265289B1 (en) | 1998-06-10 | 2001-07-24 | North Carolina State University | Methods of fabricating gallium nitride semiconductor layers by lateral growth from sidewalls into trenches, and gallium nitride semiconductor structures fabricated thereby |
| JP4070893B2 (en) * | 1998-09-22 | 2008-04-02 | 三菱電機株式会社 | Manufacturing method of semiconductor device |
| US6255198B1 (en) | 1998-11-24 | 2001-07-03 | North Carolina State University | Methods of fabricating gallium nitride microelectronic layers on silicon layers and gallium nitride microelectronic structures formed thereby |
| US6177688B1 (en) | 1998-11-24 | 2001-01-23 | North Carolina State University | Pendeoepitaxial gallium nitride semiconductor layers on silcon carbide substrates |
| US6521514B1 (en) | 1999-11-17 | 2003-02-18 | North Carolina State University | Pendeoepitaxial methods of fabricating gallium nitride semiconductor layers on sapphire substrates |
| US6653663B2 (en) | 1999-12-06 | 2003-11-25 | Matsushita Electric Industrial Co., Ltd. | Nitride semiconductor device |
| US6380108B1 (en) | 1999-12-21 | 2002-04-30 | North Carolina State University | Pendeoepitaxial methods of fabricating gallium nitride semiconductor layers on weak posts, and gallium nitride semiconductor structures fabricated thereby |
| US6403451B1 (en) | 2000-02-09 | 2002-06-11 | Noerh Carolina State University | Methods of fabricating gallium nitride semiconductor layers on substrates including non-gallium nitride posts |
| US6261929B1 (en) | 2000-02-24 | 2001-07-17 | North Carolina State University | Methods of forming a plurality of semiconductor layers using spaced trench arrays |
| JP2005252245A (en) * | 2004-02-03 | 2005-09-15 | Showa Denko Kk | Gallium nitride-based compound semiconductor wafer |
| JP2006171102A (en) * | 2004-12-13 | 2006-06-29 | Fuji Photo Film Co Ltd | Manufacturing method of optical compensation plate |
-
1994
- 1994-11-30 JP JP29543394A patent/JP2953326B2/en not_active Expired - Fee Related
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| JPH08153931A (en) | 1996-06-11 |
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