KR19980015871A - Method for manufacturing semiconductor laser diode - Google Patents
Method for manufacturing semiconductor laser diode Download PDFInfo
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- KR19980015871A KR19980015871A KR1019960035328A KR19960035328A KR19980015871A KR 19980015871 A KR19980015871 A KR 19980015871A KR 1019960035328 A KR1019960035328 A KR 1019960035328A KR 19960035328 A KR19960035328 A KR 19960035328A KR 19980015871 A KR19980015871 A KR 19980015871A
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- 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
- H01S5/30—Structure or shape of the active region; Materials used for the active region
- H01S5/32—Structure or shape of the active region; Materials used for the active region comprising PN junctions, e.g. hetero- or double- heterostructures
- H01S5/3211—Structure or shape of the active region; Materials used for the active region comprising PN junctions, e.g. hetero- or double- heterostructures characterised by special cladding layers, e.g. details on band-discontinuities
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- 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
- H01S5/22—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 ridge or stripe structure
- H01S5/2205—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 ridge or stripe structure comprising special burying or current confinement layers
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Abstract
반도체 레이져 다이오드의 제조방법에 관한 것으로, 2차 제2클래드층 형성시 양질의 결정성장을 얻기 위하여 700℃ 이상의 고온에서 AlGaAs를 성장시킬 경우에 1차 제2클래드층에서 활성층으로 아연확산이 발생하여 레이저 다이오드의 동작특성을 변화시키는 문제점이 있었다.The present invention relates to a method of manufacturing a semiconductor laser diode. In the case of growing AlGaAs at a high temperature of 700 ° C or more in order to obtain good crystal growth at the time of forming the second second clad layer, zinc diffusion occurs in the active layer from the first clad layer There has been a problem of changing the operating characteristics of the laser diode.
이를 해결하기 위한 본 발명은 약 600℃의 온도에서 양질의 결정성장을 얻을 수 있는 InGaAsP를 사용하여 2차 제2클래드층을 형성하므로 레이저 다이오드의 변화를 방지하여 소자의 신뢰성을 극대화 할 수 있다.In order to solve this problem, InGaAsP, which can obtain high quality crystal growth at a temperature of about 600 ° C, is used to form a second-order second cladding layer, so that the reliability of the device can be maximized by preventing the laser diode from being changed.
Description
본 발명은 반도체 레이저에 관한 것으로서 특히, 반도체 레이저 다이오드의 제조방법에 관한 것이다.The present invention relates to a semiconductor laser, and more particularly, to a method of manufacturing a semiconductor laser diode.
일반적으로, 레이저는 복사선의 유도방출에 의한 빛의 증폭(Light Amplification by Stimulated Emission of Radiation : LASER)를 의미한다.Generally, a laser means Light Amplification by Stimulated Emission of Radiation (LASER) by radiation of radiation.
그리고 레이저의 종류에는 루비레이저, 가스레이저, 대형 펄스레이저, 반도체 레이저 등이 있다.Types of lasers include ruby lasers, gas lasers, large pulse lasers, and semiconductor lasers.
이때, 반도체 레이저는 한 형식의 물질에 한 접합만을 포함한 동종접합(Hamo Junction) 레이저와, 광통신의 요건에 맞도록 실온에서 효율적으로 동작하도록 만든 이종접합(Hetero Junction) 레이저로 대별된다.Semiconductor lasers are roughly divided into Hamo Junction lasers, which contain only one junction of one type of material, and heterojunction lasers, which are designed to operate efficiently at room temperature to meet optical communication requirements.
이하, 종래 기술에 따른 반도체 레이저 다이오드의 제조방법을 첨부한 도면을 참조하여 설명하면 다음과 같다.Hereinafter, a conventional method of manufacturing a semiconductor laser diode will be described with reference to the accompanying drawings.
도 1a 내지 도 1d는 종래 기술에 따른 반도체 레이저 다이오드의 제조공정을 보여주는 공정단면도이다.1A to 1D are process sectional views showing a manufacturing process of a semiconductor laser diode according to the prior art.
먼저, 도 1a와 같이 n-GaAs 기판(1)상에 MOCVD(유기금속 화학기상증착) 방법에 의해 n-GaAs로 버퍼층(2)을 형성한다.First, as shown in FIG. 1A, a buffer layer 2 is formed of n-GaAs on an n-GaAs substrate 1 by MOCVD (Organometallic Chemical Vapor Deposition) method.
이어, 버퍼층(2) 전면에 n-GaAs로 제1클래드층(3)을 형성한다.Next, a first cladding layer 3 is formed on the entire surface of the buffer layer 2 with n-GaAs.
그리고 제1클래드층(3) 전면에 활성층(4)을 형성한다.Then, the active layer 4 is formed on the entire surface of the first clad layer 3.
이어, 활성층(4) 전면에 p-AlGaAs로 1차 제2클래드층(5)을 형성한다.Next, a first-order second clad layer 5 is formed on the entire surface of the active layer 4 with p-AlGaAs.
이때, 1차 제2클래드층(5)내에 아연 불순물이 주입된다.At this time, zinc impurity is implanted into the first-order second cladding layer 5.
그리고, 1차 제2클래드층(5) 전면에 n-GaAs로 전류차단층(6)을 형성하여 MOCVD에 의한 1차 성장을 마친다.Then, the current blocking layer 6 is formed of n-GaAs on the entire surface of the first-order second clad layer 5, and the first-order growth by MOCVD is completed.
이어 도 1b와 같이 통전영역을 형성하기 위하여 전류차단층(6)의 전면에 포토레지스트(7)을 증착하여 일정영역의 전류차단층(6)이 노출되도록 포토레지스트(7)를 제거한다.Next, as shown in FIG. 1B, a photoresist 7 is deposited on the entire surface of the current blocking layer 6 to remove the photoresist 7 to expose the current blocking layer 6 in a certain region.
그리고, 도 1c와 같이 포토레지스트(7)를 마스크로 노출된 전류제한층(6)을 제거하고 남아 있는 포토레지스트(7)를 제거하여 통전영역을 형성한다.Then, as shown in FIG. 1C, the exposed current limiting layer 6 is removed by using the photoresist 7 as a mask, and the remaining photoresist 7 is removed to form a current carrying region.
이어 도 1d와 같이 MOCVD 방법으로 통전영역이 형성된 전류제한층(6) 전면에 p-AlXGa1-XAs로 2차 제2클래드층(8)을 형성한다.Next, a second secondary cladding layer 8 is formed of p-Al x Ga 1 -x As on the entire surface of the current confining layer 6 formed with the energizing region by the MOCVD method as shown in FIG. 1d.
이때 p-AlXGa1-XAs의 불순물 농도 P=5∼10×1017/cm3, 조성비는 0.4≤x≤0.7이고 성장온도는 700℃이다.At this time, the impurity concentration P of the p-Al x Ga 1 -x As is 5 to 10 x 10 17 / cm 3 , the composition ratio is 0.4 ? X? 0.7, and the growth temperature is 700 占 폚.
그리고, 2차 제2클래드층(8) 전면에 p-GaAs로 캡층(9)을 형성한다.Then, a cap layer 9 is formed on the entire surface of the second secondary cladding layer 8 with p-GaAs.
이때 캡층(9)형성은 p-GaAs의 도핑(doping) 농도를 높이기 위해 약 620℃의 온도에서 이루어진다.At this time, the cap layer 9 is formed at a temperature of about 620 DEG C to increase the doping concentration of p-GaAs.
2차 제2클래드층(8)과 캡층(9)의 형성으로 2차 MOCVD 성장을 완료한다.Secondary MOCVD growth is completed by forming the second secondary cladding layer 8 and the cap layer 9.
이어 캡층(9) 상부에 제1전극(10)을 형성하고 기판(11) 하부에 제2전극(11)을 형성하여 반도체 레이저 다이오드가 완성된다.The first electrode 10 is formed on the cap layer 9 and the second electrode 11 is formed on the bottom of the substrate 11 to complete the semiconductor laser diode.
종래 기술에 따른 반도체 레이져 다이오드의 제조방법은 양질의 2차 제2클래드층(AlGaAs)을 얻기 위해 700℃ 이상의 고온공정에서 성장이 이루어지는데 상기의 고온성장이 진행되는 동안 1차 클래드층에 불순물로 첨가된 아연이 1차 제2클래드층 하부의 활성층으로 확산되어 발진파장을 변화시키고 발진개시 전류를 증가시켜 반도체 레이져 다이오드의 동작특성을 변환시키는 문제점이 있었다.In the conventional method for fabricating a semiconductor laser diode, growth is performed in a high-temperature process of 700 ° C or more in order to obtain a second-order second cladding layer (AlGaAs). During the high temperature growth, impurities The added zinc diffuses into the active layer under the first second clad layer to change the oscillation wavelength and to increase the oscillation start current to change the operating characteristics of the semiconductor laser diode.
따라서, 본 발명은 종래의 문제점을 해결하기 위하여 안출한 것으로서 본 발명의 목적은 고온성장에 의한 1차 제2클래드층에서 활성층으로의 아연확산을 방지할 수 있는 반도체 레이저 다이오드의 제조방법을 제공함에 있다.SUMMARY OF THE INVENTION Accordingly, the present invention has been made to solve the conventional problems, and it is an object of the present invention to provide a method of fabricating a semiconductor laser diode capable of preventing zinc diffusion from a first-order second clad layer to an active layer by high-temperature growth have.
도 1a 내지 도 1d는 종래의 기술에 따른 반도체 레이저 다이오드의 제조공정을 보여주는 공정단면도이고,FIGS. 1A to 1D are cross-sectional views showing a manufacturing process of a semiconductor laser diode according to a conventional technique,
도 2a 내지 도 2e는 본 발명에 따른 반도체 레이져 다이오드의 제조공정을 보여주는 공정단면도이다.2A to 2E are process cross-sectional views illustrating a manufacturing process of a semiconductor laser diode according to the present invention.
*도면의 주요부분에 대한 부호의 설명*Description of the Related Art [0002]
21 : 기판22 : 버퍼층21: substrate 22: buffer layer
23 : 제1클래드층24 : 활성층23: first clad layer 24: active layer
25 : 1차 제2클래드층26 : 전류차단층25: primary second clad layer 26: current blocking layer
27 : 포토 레지스트28 : 2차 제2클래드층27: Photoresist 28: Secondary second cladding layer
29 : 캡층30 : 제1전극29: cap layer 30: first electrode
31 : 제2전극31: Second electrode
본 발명에 따른 반도체 레이저 다이오드의 제조방법은 600℃ 정도의 성장온도에서 양질의 결정이 성장되는 InGaAsP를 2차 제2클래드층으로 사용함으로서 아연의 확산을 방지하여 소자의 신뢰성을 극대화 할 수 있는 특징이 있다.The method of manufacturing a semiconductor laser diode according to the present invention uses InGaAsP, which is grown at a growth temperature as high as about 600 ° C, as a second-type second clad layer, thereby preventing diffusion of zinc and maximizing reliability of the device .
이하 본 발명에 따른 반도체 레이저 다이오드 제조방법을 첨부한 도면을 참조하여 설명하면 다음과 같다.Hereinafter, a method for fabricating a semiconductor laser diode according to the present invention will be described with reference to the accompanying drawings.
도 2a 내지 도 2e는 본 발명에 따른 반도체 레이저 다이오드의 제조공정을 보여주는 공정단면도이다.2A to 2E are process cross-sectional views illustrating a manufacturing process of a semiconductor laser diode according to the present invention.
먼저, p-GaAs 기판(21)상에 MOCVD(Metal Organic Chemical Vapor Deposition : 유기금속 화학기상증착) 방법으로 p-GaAs 버퍼층(22)을 약 0.5㎛두게로 형성한다.First, a p-GaAs buffer layer 22 is formed on the p-GaAs substrate 21 by a metal organic chemical vapor deposition (MOCVD) method to a thickness of about 0.5 μm.
이때, 불순물 농도 n=1∼3×1018/cm3이다.At this time, the impurity concentration n is 1 to 3 x 10 18 / cm 3 .
이어, n-GaAs버퍼층(22) 전면에 n-AlXGa1-XAs 제1클래드층(23)을 약 1.0㎛ 두께로 형성한다.Next, an n-Al x Ga 1 -x As first cladding layer 23 is formed to a thickness of about 1.0 탆 on the entire surface of the n-GaAs buffer layer 22.
이때, 불순물 농도 n=3∼10×1017/cm3이고 조성비는 0.4≤x≤0.7이다.At this time, the impurity concentration n is 3 to 10 x 10 17 / cm 3 and the composition ratio is 0.4? X? 0.7.
그리고, 제1클래드층(23) 전면에 780nm 파장을 가지는 활성층(24)을 형성한다.Then, an active layer 24 having a wavelength of 780 nm is formed on the entire surface of the first clad layer 23.
이어, 활성층(24) 전면에 n-AlXGa1-XAs 1차 제2클래드층(25)을 0.2∼0.4㎛ 두께로 형성한다.Next, an n-Al x Ga 1 -x As first-order second clad layer 25 is formed to a thickness of 0.2 to 0.4 μm on the entire surface of the active layer 24.
이때 1차 제2클래드층(25)내에는 아연 불순물이 주입되고 불순물 농도 P=3∼7×1017/cm3이며 조성비는 0.4≤x≤0.7이다.At this time, zinc impurity is injected into the first-order second cladding layer 25, the impurity concentration is P = 3 to 7 × 10 17 / cm 3, and the composition ratio is 0.4 ≦ x ≦ 0.7.
그리고, 1차 제2클래드층(25) 전면에 n-GaAs 전류차단층(26)은 0.8∼1.0㎛두께로 형성하여 MOVCD에 의한 1차 성장을 마친다.The n-GaAs current blocking layer 26 is formed to a thickness of 0.8 to 1.0 m on the entire surface of the first second cladding layer 25 to complete the first growth by MOVCD.
이때 1차 성장은 약 700℃의 온도에서 이루어진다.At this time, the primary growth is carried out at a temperature of about 700 ° C.
이어 도 2b와 같이 통전영역을 형성하기 위하여 전류차단층(26)의 전면에 포토레지스트(27)를 증착하여 일정영역의 전류차단층(26)이 노출되도록 포토레지스트(27)를 제거한다.Next, as shown in FIG. 2B, a photoresist 27 is deposited on the entire surface of the current blocking layer 26 to remove the photoresist 27 so that the current blocking layer 26 in a certain region is exposed.
그리고, 도 2c와 같이 포토레지스트(27)를 마스크로 노출된 전류제한층(26)을 제거하고 남아 있는 포토레즈스트(27)를 제거하여 통전영역을 형성한다.Then, as shown in FIG. 2C, the exposed current limiting layer 26 is removed by using the photoresist 27 as a mask, and the remaining photoresist 27 is removed to form a current carrying region.
이어 도 1d와 같이 MOCVD 방법으로 통전영역이 형성된 전류제한층(26) 전면에 p-InXGa1-XAsyP1-y2차 제2클래드층(28)을 0.5∼0.6㎛두께로 증착한다.Following a current confined layer 26 over the entire surface of the p-In X Ga 1-X As y P 1-y 2 primary second cladding layer 28, the current flow region formed by MOCVD method as shown in Fig. 1d to the thickness 0.5~0.6㎛ Lt; / RTI >
이때 불순물 농도 p=5∼10×1017/cm3이고 조성비 x는 약 0.45, y는 0.1이며 성장온도는 약 600℃이다.In this case, the impurity concentration is p = 5 to 10 × 10 17 / cm 3 , the composition ratio x is about 0.45, y is about 0.1, and the growth temperature is about 600 ° C.
종래 기술에 따른 p-AlGaAs를 양질의 결정으로 형성시키기 위해서는 700℃ 이상의 고온에서 성장시켜야 하므로 1차 제2클래드층(26)에 함유된 아연이 활성층(24)으로 확산되었지만, 본 발명에 따른 p-InGaAsP는 600℃의 온도에서도 양질의 결정으로 형성시킬 수 있으므로 아연확산을 방지할 수 있다.In order to form p-AlGaAs according to the prior art as high-quality crystals, zinc must be grown at a high temperature of 700 ° C or more, so that zinc contained in the first-order second cladding layer 26 is diffused into the active layer 24. However, -InGaAsP can be formed with high quality crystals even at a temperature of 600 DEG C, so zinc diffusion can be prevented.
그리고, 도 2e와 같이 2차 제2클래드층(28) 전면에 p-GaAs 캡층(29)을 약 3㎛ 두께로 형성하여 2차 MOCVD 성장이 완료된다.As shown in FIG. 2E, the p-GaAs cap layer 29 is formed to a thickness of about 3 .mu.m on the entire surface of the second secondary cladding layer 28, and the secondary MOCVD growth is completed.
이때, 상기 캡층(29)의 형성은 종래의 기술에서 설명한 바와 같이 도핑농도를 높이기 위해 620℃ 이하에서 이루어져야 하는데, 본 발명은 종래의 기술과 달리 약 600℃의 온도에서 2차 제2클래드층(18)이 형성되고 이어서 캡층(29)을 형성시키므로 종래의 기술과 달리 온도를 재조정할 필요가 없고 2차 제2클래드층 성장과 캡층의 성장온도를 일정하게 유지한다.In order to increase the doping concentration, the cap layer 29 should be formed at a temperature of 620 캜 or less as described in the related art. However, unlike the prior art, the cap layer 29 is formed at a temperature of about 600 캜, 18 is formed and the cap layer 29 is formed. Therefore, unlike the conventional technique, it is not necessary to readjust the temperature, and the growth of the second second clad layer and the growth temperature of the cap layer are kept constant.
이어, 캡층(29) 상부에 제1전극(30)을 형성하고 기판(21) 하부에 제2전극(31)을 형성하여 반도체 레이저 다이오드가 완성된다.A first electrode 30 is formed on the cap layer 29 and a second electrode 31 is formed on the bottom of the substrate 21 to complete the semiconductor laser diode.
본 발명에 따른 반도체 레이저 다이오드의 제조방법은 다음과 같은 효과가 있다.The method of manufacturing a semiconductor laser diode according to the present invention has the following effects.
첫째, 2차 제2클래드층을 형성하기 위해 InGaAsP를 사용할 경우 AlGaAs에 비해 약 100℃이상 성장온도를 낮게 즉, 600℃에서 성장시킬 수 있으므로 캡층 형성시 온도를 재조정할 필요가 없으므로 공정시간을 단축하여 생산성을 향상시킬 수 있는 효과가 있다.First, when InGaAsP is used to form the second second clad layer, since the growth temperature can be lowered to about 100 ° C or lower, that is, 600 ° C compared to AlGaAs, it is not necessary to readjust the temperature at the time of forming the cap layer, So that the productivity can be improved.
둘째, 2차 제2클래드층 형성이 600℃에서 이루어져 활성층으로의 아연확산으로 인한 발진파장의 변화 및 발진개시 전류의 증가를 막아 소자의 신뢰성을 극대화할 수 있는 효과가 있다.Secondly, the formation of the second second clad layer is performed at 600 ° C, which is effective in preventing the change of the oscillation wavelength due to the zinc diffusion into the active layer and the increase of the oscillation start current, thereby maximizing the reliability of the device.
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