Source: http://www.google.com/patents/US6162656?dq=6004266
Timestamp: 2013-12-21 10:27:41
Document Index: 718370723

Matched Legal Cases: ['art 2', 'art 2', 'art. 2', 'art. 2', 'art. 1', 'art. 1']

Patent US6162656 - Manufacturing method of light emitting device - Google PatentsSearch Images Maps Play YouTube News Gmail Drive More »Sign inAdvanced Patent SearchPatentsA method of manufacturing a light emitting device, including the steps of: forming an active layer composed of a compound semiconductor containing indium by a vapor phase growth method; and forming a cap layer composed of a compound semiconductor on said active layer by a vapor phase growth method at...http://www.google.com/patents/US6162656?utm_source=gb-gplus-sharePatent US6162656 - Manufacturing method of light emitting deviceAdvanced Patent SearchPublication numberUS6162656 APublication typeGrantApplication numberUS 09/427,694Publication dateDec 19, 2000Filing dateOct 27, 1999Priority dateApr 26, 1996Fee statusPaidAlso published asCN1169036A, CN1220278C, CN1540775A, CN100353573C, DE69735078D1, DE69735078T2, EP0803916A2, EP0803916A3, EP0803916B1, EP1453112A1, EP2383846A2, US5990496, USRE42074Publication number09427694, 427694, US 6162656 A, US 6162656A, US-A-6162656, US6162656 A, US6162656AInventorsTakashi Kano, Tatsuya Kunisato, Yasuhiko Matsushita, Yasuhiro Ueda, Katsumi YagiOriginal AssigneeSanyo Electric Co., Ltd.Export CitationBiBTeX, EndNote, RefManPatent Citations (15), Non-Patent Citations (12), Referenced by (21), Classifications (21), Legal Events (3) External Links: USPTO, USPTO Assignment, EspacenetManufacturing method of light emitting deviceUS 6162656 AAbstract A method of manufacturing a light emitting device, including the steps of: forming an active layer composed of a compound semiconductor containing indium by a vapor phase growth method; and forming a cap layer composed of a compound semiconductor on said active layer by a vapor phase growth method at a growth temperature approximately equal to or lower than a growth temperature for said active layer.
What is claimed is: 1. A method of manufacturing a light emitting device, comprising the steps of:forming an active layer composed of a nitride system semiconductor by a vapor phase growth method; forming a cap layer composed of a nitride system semiconductor on said active layer by a vapor phase growth method at a growth temperature approximately equal to or lower than a growth temperature for said active layer; and forming a cladding layer composed of a nitride system semiconductor of one conductivity type on said cap layer by a vapor phase growth method; wherein said cap layer has a lower impurity concentration than said cladding layer. 2. The method of manufacturing a light emitting device according to claim 1, whereinsaid active layer is composed of a III-V group nitride system semiconductor, said cap layer is composed of a III-V group nitride system semiconductor, and said cladding layer is composed of a III-V group nitride system semiconductor. 3. The method of manufacturing a light emitting device according to claim 2, wherein said step of forming a cladding layer includes forming said cladding layer at a growth temperature higher than the temperature allowing crystal growth of said active layer.
4. The method of manufacturing a light emitting device according to claim 3, whereinsaid cap layer is composed of Al.sub.u Ga.sub.1-u N, said cladding layer is composed of Al.sub.z Ga.sub.1-z N of one conductivity type, and the Al composition ratio u of said cap layer is smaller than the Al composition ratio z of said cladding layer. 5. The method of manufacturing a light emitting device according to claim 4, wherein the Al composition ratio u of said cap layer is approximately equal to or smaller than 0.1.
8. The method of manufacturing a light emitting device according to claim 1, wherein the step of forming said cap layer includes forming said cap layer at a growth temperature of not lower than 700 than 950
11. The method of manufacturing a light emitting device according to claim 1, wherein said active layer has a quantum well structure including an InGaN quantum well layer and a GaN quantum barrier layer, andthe step of forming said active layer includes forming said GaN quantum barrier layer at a growth temperature of not lower than 700 higher than 950 Description
TABLE 1______________________________________Name of layer   Growth temperature (______________________________________Buffer layer 102            600  N-type contact layer 103 1150  Active layer 104  860  P-type cladding layer 105 1150  P-type contact layer 106 1150______________________________________
The growth temperature for the cap layer is preferably set to a temperature which allows crystal growth of the active layer. The active layer is preferably formed at a growth temperature not lower than 700 and not higher than 950 growth temperature not lower than 700 950 growth temperature suppresses elimination of constituent elements such as indium from the active layer.
It is preferable that the active layer has a quantum well structure including an InGaN quantum well layer and a GaN quantum barrier layer and the GaN quantum barrier layer is formed by a vapor phase growth method at a growth temperature not lower than 700 950 indium from the InGaN quantum well layer is suppressed, thus enabling larger luminous intensity. An InGaN having an In composition ratio lower than that of the quantum well layer may be used as the quantum barrier layer.
In FIG. 1, formed in order on a sapphire insulating substrate 1 are a 110-Å-thick undoped Al.sub.x Ga.sub.1-x N (x=0.5) buffer layer 2, a 0.2-μm-thick undoped GaN underlayer 3, a 4-μm-thick Si-doped n-type GaN contact layer 4 also serving as an n-type cladding layer, and a 0.2-μm-thick Zn- and Si-doped In.sub.q Ga.sub.1-q N (q=0.05) active layer 5. Formed in order on the InGaN active layer 5 are a 200-Å-thick undoped GaN cap layer 6 for preventing crystal deterioration of the active layer 5, a 0.15-μm-thick Mg-doped p-type Al.sub.z Ga.sub.1-z N (z=0.2) cladding layer 7, and a 0.3-μm-thick Mg-doped p-type GaN contact layer 8.
First, the substrate 1 is placed in a metal organic chemical vapor deposition apparatus. Then, with the substrate 1 held at a non-single crystal growth temperature, e.g., a growth temperature (a substrate temperature) of 600 buffer layer 2 is grown on the substrate 1 by using H.sub.2 and N.sub.2 as carrier gas and ammonia, trimethylgallium (TMG) and trimethylaluminum (TMA) as material gas.
Subsequently, with the substrate 1 held at a single crystal growth temperature, or a growth temperature preferably of 1000-1200 e.g., 1150 grown on the buffer layer 2 by using H.sub.2 and N.sub.2 as carrier gas and ammonia and trimethylgallium (TMG) as material gas.
Then with the substrate 1 held at a single crystal growth temperature, or a growth temperature preferably of 1000-1200 C., the single-crystal Si-doped n-type GaN contact layer 4 is grown on the underlayer 3 by using H.sub.2 and N.sub.2 as carrier gas, ammonia and trimethylgallium (TMG) as material gas, and SiH.sub.4 as dopant gas.
Next, with the substrate 1 held at a single crystal growth temperature, or preferably at a growth temperature of 700-950 860 is grown on the n-type contact layer 4 by a1) using H.sub.2 and N.sub.2 as carrier gas, ammonia, triethylgallium (TEG) and trimethylindium (TMI) as material gas, and SiH.sub.4 and diethylzinc (DEZ) as dopant gas.
Subsequently, with the substrate 1 held at a temperature equal to or lower than the growth temperature for the active layer 5, or at 860 in this embodiment, the single-crystal undoped GaN cap layer 6 is grown on the InGaN active layer 5 continuously following the growth of the active layer 5 by using H.sub.2 and N.sub.2 as carrier gas, and ammonia and trimethylgallium (TMG) as material gas. Triethylgallium (TEG) may be used in place of trimethylgallium (TMG).
Then with the substrate 1 held at a single crystal growth temperature, i.e., preferably at a growth temperature of 1000-1200 1150 is grown on the GaN cap layer 6 by using H.sub.2 and N.sub.2 as carrier gas, ammonia, trimethylgallium (TMG) and trimethylaluminum (TMA) as material gas, and Cp.sub.2 Mg (cyclopentadienylmagnesium) as dopant gas.
Next, with the substrate 1 held at a single crystal growth temperature, i.e., preferably at a growth temperature of 1000-1200 1150 grown on the p-type cladding layer 7 by using H.sub.2 and N.sub.2 as carrier gas, ammonia and trimethylgallium (TMG) as material gas, and Cp.sub.2 Mg (cyclopentadienylmagnesium) as dopant gas.
Then a heat treatment is performed at 750-800 in an atmosphere of nitrogen to activate the dopants in the p-type contact layer 8 and the p-type cladding layer 7 to obtain high carrier concentration and to correct crystal deterioration in the n-type contact layer 4 caused by the etching.
Then the p electrode 9 composed of Au is formed by evaporation, or the like, on the p-type contact layer 8 and the n electrode 10 composed of Al is formed by evaporation or the like on the n electrode formation region of the n-type contact layer 4. A heat treatment at 500 applied to cause the p electrode 9 and the n electrode 10 to come into ohmic contact with the p-type contact layer 8 and the n-type contact layer 4, respectively, to form the light emitting diode shown in FIG. 1.
This embodiment differs from the first embodiment in that it uses a 200-Å-thick undoped Al.sub.u Ga.sub.1-u N layer as the cap layer 6 in place of the undoped GaN layer. The value of u is approximately 0.1 and 0.2. This Al.sub.u Ga.sub.1-u N layer, too, is formed by MOCVD at the same temperature as the growth temperature for the active layer 5, at 860 gas and ammonia, trimethylgallium (TMG) and trimethylaluminum (TMA) are used as material gas. Triethylgallium (TEG) may be used instead of trimethylgallium (TMG).
However, as compared with the 200-Å-thick undoped GaN cap layer 6 in the first embodiment regarded as providing a luminous intensity of 450 (arbitrary unit), an undoped Al.sub.u Ga.sub.1-u N cap layer 6 with an Al composition ratio u of about 0.1 in the second embodiment provided a luminous intensity smaller than half thereof, 190 (arbitrary unit).
The aforementioned embodiments use an active layer with a non-quantum-well structure as the active layer 5, rather than a quantum-well structure. However, needless to say, an active layer with a single-quantum-well structure or a multi-quantum-well structure may be used. For example, the active layer may have a single-quantum-well structure formed of an In.sub.s Ga.sub.1-s N (1&gt;s&gt;0) quantum well layer, or a multi-quantum-well structure formed of an In.sub.s Ga.sub.1-s N (1&gt;s&gt;0) quantum well layer and an In.sub.r Ga.sub.1-r N (1&gt;s&gt;r≧0) quantum barrier layer.
When using a multi-quantum-well structure formed of an In.sub.s Ga.sub.1-s N (1&gt;s&gt;0) quantum well layer and a GaN quantum barrier layer, it is preferable to form the GaN quantum barrier layer at a growth temperature not lower than 700 also preferable to grow the quantum well layer and the quantum barrier layer at approximately equal growth temperatures.
This semiconductor laser device is manufactured by performing crystal growth once by using chemical vapor deposition, such as MOCVD. When manufacturing, the undoped AlGaN buffer layer 12 is formed at a growth temperature or 600 GaN contact layer 14 and the n-type AlGaN cladding layer 15 are formed at a growth temperature of 1150 GaN cap layer 17 are formed at a growth temperature of 700-950 and the p-type AlGaN cladding layer 18, the n-type current blocking layer 19 and the p-type GaN contact layer 20 are formed at a growth temperature of 1150
This semiconductor laser device is manufactured by performing crystal growth three times by using chemical vapor deposition such as MOCVD. When manufacturing, the undoped AlGaN buffer layer 32 is formed at a growth temperature of 600 GaN contact layer 34 and the n-type AlGaN cladding layer 35 are formed at a growth temperature of 1150 undoped GaN cap layer 37 are formed at a growth temperature of 700-950 layer 39, the n-type current blocking layer 40 and the p-type GaN contact layer 41 are formed at a growth temperature of 1150
The semiconductor laser device of this embodiment is formed by performing crystal growth once by using chemical vapor deposition such as MOCVD. When manufacturing, the undoped AlGaN buffer layer 52 is formed at a growth temperature of 600 GaN contact layer 54 and the n-type AlGaN cladding layer 55 are formed at a growth temperature of 1150 undoped GaN cap layer 57 are formed at a growth temperature of 700-950 GaN contact layer 59 are formed at a growth temperature of 1150
With the structure shown in FIG. 6, for example, an n-type AlGaN layer 72 and an InGaN layer 73 are formed in order on an n-type GaN layer 71 and a p-type SiC layer 75 is formed above the InGaN layer 73 with an undoped GaN cap layer 74 therebetween. In this case, the InGaN layer 73 and the GaN cap layer 74 are formed at a growth temperature of 700-950 the p-type SiC layer 75 is formed at a growth temperature of 1300-1500 GaN cap layer 74 on the InGaN layer 73 suppresses elimination of constituent elements such as In from the InGaN layer 73.
In the structure of FIG. 7, an InGaN layer 82 is formed on an n-type SiC layer 81 and a p-type SiC layer 84 is formed above the InGaN layer 82 with an undoped GaN cap layer 83 therebetween. In this case, as well, the InGaN layer 82 and the undoped GaN cap layer 83 are formed at a growth temperature of 700-950 a growth temperature of 1300-1500 formation of the undoped GaN cap layer 83 on the InGaN layer 82 suppresses elimination of constituent elements such as In from the InGaN layer 82.
Patent CitationsCited PatentFiling datePublication dateApplicantTitleUS5345463 *Apr 13, 1993Sep 6, 1994Matsushita Electric Industrial Co., Ltd.Semiconductor laser with improved oscillation wavelength reproducibilityUS5393993 *Dec 13, 1993Feb 28, 1995Cree Research, Inc.Buffer structure between silicon carbide and gallium nitride and resulting semiconductor devicesUS5495115 *Aug 8, 1994Feb 27, 1996Hitachi, Ltd.Semiconductor crystalline laminate structure, forming method of the same, and semiconductor device employing the sameUS5563422 *Apr 28, 1994Oct 8, 1996Nichia Chemical Industries, Ltd.Gallium nitride-based III-V group compound semiconductor device and method of producing the sameUS5578839 *Nov 17, 1993Nov 26, 1996Nichia Chemical Industries, Ltd.Light-emitting gallium nitride-based compound semiconductor deviceUS5583878 *Jun 23, 1994Dec 10, 1996The Furukawa Electric Co., Ltd.Semiconductor optical deviceUS5592501 *Sep 20, 1994Jan 7, 1997Cree Research, Inc.Low-strain laser structures with group III nitride active layersUS5656832 *Mar 8, 1995Aug 12, 1997Kabushiki Kaisha ToshibaSemiconductor heterojunction device with ALN buffer layer of 3nm-10nm average film thicknessUS5777350 *Nov 30, 1995Jul 7, 1998Nichia Chemical Industries, Ltd.Nitride semiconductor light-emitting deviceUS5866440 *Oct 14, 1997Feb 2, 1999Sharp Kabushiki KaishaMethod of making compound semiconductor light emitting device having evaporation preventing layer Al.sub.x Ga.sub.(1-x) NUS5990496 *Apr 25, 1997Nov 23, 1999Sanyo Electric Co., Ltd.Light emitting device with cap layerEP0497350A1 *Jan 30, 1992Aug 5, 1992Nichia Kagaku Kogyo K.K.Crystal growth method for gallium nitride-based compound semiconductorJPH0774431A * Title not availableJPH06283825A * Title not availableJPH07249795A * Title not available* Cited by examinerNon-Patent CitationsReference1 *Compound Semiconductor, p. 7 Jan./Feb. 1996.2Compound Semiconductor, p. 7--Jan./Feb. 1996.3Nakamura S. et al. "Superbright green InGaN single-quantum-well-structure LEDs" Japanese Journal Of Applied Physics, Part 2 (Letters), Oct. 15, 1995, Japan, vol. 34, No. 10B, pp. L1332-L1335, XP000702227.4 *Nakamura S. et al. Superbright green InGaN single quantum well structure LEDs Japanese Journal Of Applied Physics, Part 2 (Letters), Oct. 15, 1995, Japan, vol. 34, No. 10B, pp. L1332 L1335, XP000702227.5Nakamura S: "III-V nitride-based LEDs" Conf. On Diamond, Diamond-Like And Related Materials, Barcelona, Sep. 10-15, 1995, vol. 5, No. 3-5, pp. 496-500, XP000627554.6 *Nakamura S: III V nitride based LEDs Conf. On Diamond, Diamond Like And Related Materials, Barcelona, Sep. 10 15, 1995, vol. 5, No. 3 5, pp. 496 500, XP000627554.7 *Shuji Nakamura et al.; Appl. Phys. Lett. 69 (10), pp. 1477 1479; Sep. 2, 1996.8Shuji Nakamura et al.; Appl. Phys. Lett. 69 (10), pp. 1477-1479; Sep. 2, 1996.9 *Shuji Nakamura et al.; Jpn. J. Appl. Phys. vol. 35, pp. L217 220, Part. 2, No. 2B; Feb. 15, 1996.10Shuji Nakamura et al.; Jpn. J. Appl. Phys. vol. 35, pp. L217-220, Part. 2, No. 2B; Feb. 15, 1996.11 *Shuji Nakamura et al.; Jpn. J. Appl. Phys. vol. 35, pp. L74 L76, Part. 1, No. 1B; Jan. 15, 1996.12Shuji Nakamura et al.; Jpn. J. Appl. Phys. vol. 35, pp. L74-L76, Part. 1, No. 1B; Jan. 15, 1996.* Cited by examinerReferenced byCiting PatentFiling datePublication dateApplicantTitleUS6720196 *May 6, 2002Apr 13, 2004Sanyo Electric Co., Ltd.Nitride-based semiconductor element and method of forming nitride-based semiconductorUS6738175 *Dec 12, 2000May 18, 2004Nichia CorporationLight emitting deviceUS6952024 *Feb 13, 2003Oct 4, 2005Cree, Inc.Group III nitride LED with silicon carbide cladding layerUS7012283 *Sep 17, 2001Mar 14, 2006Sharp Kabushiki KaishaNitride semiconductor light emitting element and optical device containing itUS7067847 *Dec 14, 2001Jun 27, 2006Ngk Isulators, Ltd.Semiconductor elementUS7119378Nov 2, 2004Oct 10, 2006Nichia CorporationNitride semiconductor deviceUS7120181 *Mar 22, 2000Oct 10, 2006Sanyo Electric Co., Ltd.Semiconductor laser device and method of fabricating the sameUS7358522Nov 5, 2002Apr 15, 2008Nichia CorporationSemiconductor deviceUS7646009Feb 7, 2006Jan 12, 2010Nichia CorporationNitride semiconductor deviceUS7667226Feb 21, 2008Feb 23, 2010Nichia CorporationSemiconductor deviceUS7700384Feb 15, 2007Apr 20, 2010Sharp Kabushiki KaishaNitride semiconductor light emitting device and manufacturing method thereofUS7750337Sep 12, 2007Jul 6, 2010Nichia CorporationNitride semiconductor deviceUS8030745Feb 28, 2005Oct 4, 2011Semiconductor Energy Laboratory Co., Ltd.ID chip and IC cardUS8044384Feb 2, 2010Oct 25, 2011Cree, Inc.Group III nitride based quantum well light emitting device structures with an indium containing capping structureUS8211726Feb 16, 2007Jul 3, 2012Sharp Kabushiki KaishaMethod of manufacturing nitride semiconductor light emitting deviceUS8227268 *Oct 19, 2007Jul 24, 2012Cree, Inc.Methods of fabricating group III nitride based light emitting diode structures with a quantum well and superlattice, group III nitride based quantum well structures and group III nitride based superlattice structuresUS8309948Jun 11, 2010Nov 13, 2012Nichia CorporationNitride semiconductor deviceUS8536615Aug 2, 2010Sep 17, 2013Cree, Inc.Semiconductor device structures with modulated and delta doping and related methodsUS8546787Sep 30, 2011Oct 1, 2013Cree, Inc.Group III nitride based quantum well light emitting device structures with an indium containing capping structureUS8575592Feb 3, 2010Nov 5, 2013Cree, Inc.Group III nitride based light emitting diode structures with multiple quantum well structures having varying well thicknessesUSRE42074 *Dec 18, 2002Jan 25, 2011Sanyo Electric Co., Ltd.Manufacturing method of light emitting device* Cited by examinerClassifications U.S. Classification438/46, 438/45, 438/22International ClassificationH01L33/32, H01L33/06, H01S5/343, H01S5/00, H01L33/12, H01S5/323, H01L33/34, H01L33/00Cooperative ClassificationH01S5/32341, H01S2304/04, H01L33/32, H01S5/221, H01S2301/173, H01S5/0213, H01L33/007, H01S5/2231European ClassificationH01L33/00G3B2, H01L33/32Legal EventsDateCodeEventDescriptionJun 6, 2008FPAYFee paymentYear of fee payment: 8May 12, 2004FPAYFee paymentYear of fee payment: 4May 13, 2003RFReissue application filedEffective date: 20021218RotateOriginal ImageGoogle Home - Sitemap - USPTO Bulk Downloads - Privacy Policy - Terms of Service - About Google Patents - Send FeedbackData provided by IFI CLAIMS Patent Services©2012 Google