Source: http://www.google.com/patents/US8050304?dq=7751826
Timestamp: 2016-07-27 17:38:39
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Matched Legal Cases: ['Application No. 2', 'Application No. 08160129', 'Application No. 07254498', 'Application No. 2003', 'Application No. 2003', 'Application No. 200710142217', 'Application No. 10', 'Application No. 200710142217', 'Application No. 200480027969']

Patent US8050304 - Group-III nitride based laser diode and method for fabricating same - Google PatentsSearch Images Maps Play YouTube News Gmail Drive More »Sign inPatentsA laser diode comprising a first separate confinement heterostructure and an active region on the first separate confinement heterostructure. A second separate confinement heterostructure is on the active region and one or more epitaxial layers is on the second separate confinement heterostructure. A...http://www.google.com/patents/US8050304?utm_source=gb-gplus-sharePatent US8050304 - Group-III nitride based laser diode and method for fabricating sameAdvanced Patent SearchPublication numberUS8050304 B2Publication typeGrantApplication numberUS 12/880,392Publication dateNov 1, 2011Filing dateSep 13, 2010Priority dateNov 15, 2006Fee statusPaidAlso published asUS7813400, US20080112453, US20100330720Publication number12880392, 880392, US 8050304 B2, US 8050304B2, US-B2-8050304, US8050304 B2, US8050304B2InventorsSteven DenBaars, Shuji Nakamura, Monica HansenOriginal AssigneeCree, Inc.Export CitationBiBTeX, EndNote, RefManPatent Citations (50), Non-Patent Citations (65), Referenced by (2), Classifications (20), Legal Events (1) External Links: USPTO, USPTO Assignment, EspacenetGroup-III nitride based laser diode and method for fabricating same
US 8050304 B2Abstract
1. A method for fabricating a laser diode, comprising;
growing a first guiding layer on said growth wafer;
growing an active region on said first guiding layer;
growing a second guiding layer on said active region;
growing one or more epitaxial layers on said second guiding layer; and
etching a ridge and first mesa in said epitaxial layers, said first mesa being 0.1 to 0.2 microns above said second guiding layer.
14. The method of claim 13, wherein said can is filled with an inert gas. Description
This application is a divisional of and claims the benefit of U.S. patent application Ser. No. 11/600,617, to Denbaars et al., filed on Nov. 15, 2006 now U.S. Pat. No. 7,813,400, and having the same title as the present application.
A known characteristic of laser diodes (and light emitting diodes) is that the frequency of radiation that can be produced by the particular laser diode is related to the bandgap of the particular semiconductor material. Smaller bandgaps produce lower energy, shorter wavelength photons, while wider bandgaps produce higher energy, shorter wavelength photons. One semiconductor material commonly used for lasers is indium gallium aluminum phosphide (InGaAlP), which has a bandgap that is generally dependent upon the mole of atomic fraction of each element present. This material, regardless of the different element atomic fraction, produces only light in the red portion of the visible spectrum, i.e., about 600 to 700 nanometers (nm).
Laser diodes that produce shorter wavelengths not only produce different colors of radiation, but offer other advantages. For example, laser diodes, and in particular edge emitting laser diodes, can be used with optical storage and memory devices (e.g. compact disks (CD) digital video disks (DVD), high definition (HD) DVDs, and Blue Ray DVDs). Their shorter wavelength enables the storage and memory devices to hold proportionally more information. For example, an optical storage device storing information using blue light can hold approximately 32 times the amount of information as one using red light, using the same storage space. There are also applications for shorter wavelength laser in medical systems and projection displays. This has generated interest in Group-III nitride material for use in laser diodes, and in particular gallium nitride (GaN). GaN can produce light in the blue and ultra violet (UV) frequency spectrums because of its relatively high bandgap (3.36 eV at room temperature). This interest has resulted in developments related to the structure and fabrication of Group-III nitride based laser diodes [For example see U.S. Pat. Nos. 5,592,501 and 5,838,706 to Edmond et al].
Embodiments of the present invention may be particularly well suited for use in nitride-based devices such as Group III-nitride based laser diodes. As used herein, the term “Group III nitride” refers to those semiconducting compounds formed between nitrogen and the elements in Group III of the periodic table, usually aluminum (Al), gallium (Ga), and/or indium (In). The term also refers to ternary and quaternary compounds, such as AlGaN and AlInGaN. As well understood by those in this art, the Group III elements can combine with nitrogen to form binary (e.g., GaN), ternary (e.g., AlGaN and AlInN), and quaternary (e.g., AlInGaN) compounds. These compounds all have empirical formulas in which one mole of nitrogen is combined with a total of one mole of the Group III elements. Accordingly, formulas such as Al.sub.xGa.sub.1-xN, where 0�1, are often used to describe them.
The present invention can be utilized with many different laser diode structures arranged in different ways, with the laser diode 10 being only one example of such a laser diode structure. The laser diode 10 comprises a substrate 12 that can be made of many different materials such as sapphire, silicon carbide, or GaN. The preferred laser diode 10 is formed on a free-standing GaN substrate lateral epitaxial overgrown (LEO) pendeo GaN, or a substrate with a lateral epitaxial overgrowth layer on the a substrate such as silicon or silicon carbide. Alternatively, the substrate can be GaN grown by hybrid vapor-phase epitaxy (HVPE).
An n-type contact layer 14 is grown on the substrate and comprises a semiconductor material suitable for spreading current from an n-contact to the active region. Many different materials can be used for the n-type contact layer, with a preferred material being n-type doped GaN, with a suitable dopant being silicon (Si). As further described below, for laser diodes that are formed on conductive substrates, the n-contact can be formed on the substrate 12 and currents from an electrical signal applied to the n-contact conducts through the substrate 12 and n-contact layer 14, to the active region of the laser diode 10. For laser diodes formed on non-conductive substrates or substrates that do not efficiently spread current, a lateral geometry can be used for contacting the device. In these embodiments the laser diode 10 can be etched to form a mesa in the n-type contact layer 14 and the n-contact is deposited on the contact layer mesa. Current spreads from the contact, through the n-type contact layer 14 and to the laser diode's active region.
An n-type guiding layer 20 is formed on the n-type SLS 18 with the guiding layer also referred to as a separate confinement heterostructure (SCH). The n-type SCH 20 serves as part of the light path to the edges of the laser diode 10 and ultimately out the emission edge of the laser diode 10. The light from the active region traveling toward the waveguiding elements (n-type SLS 20 and the p-type SLS described below) is reflected, and light traveling toward the laser diode's edges is reflected until stimulated emission is out one of the edges. The n-type SCH layer 20 and p-type SCH layer serve as the primary reflection cavity for this reflected light. The n-type SCH 22 can comprise many different materials with a preferred material being n-type doped GaN grown with Si doping.
The laser diode 10 further comprises an electron blocking layer 24 formed on the MQW active region 22. The blocking layer 24 comprises a material that blocks electrons from passing from the MOW active region 22 into the p-type SCH layer (described below), but lets holes pass through to form the p-type SCH layer to the MQW active region 22. By blocking electrons, the blocking layer encourages recombination in the MQW active region 22. The blocking layer can be made of many different materials, with a suitable material being p-type AlGaN with Mg doping. A p-type guiding layer or SCH 26 is formed on the electron blocking layer 24. The p-type SCH 26 can be made of many different materials with a suitable material being p-type GaN with Mg doping.
Referring back to FIG. 3, the laser diode 10 also comprises a p-contact (ohmic metal) 34 on the top surface of the ridge 32, which is the p-contact layer 32. An n-contact (ohmic metal) 36 can also be included on the substrate 12 for those embodiments having a conductive substrate. The p- and n-contacts 34, 36 can be made of many different materials, with preferred p-contacts being made of platinum (Pt), gold (Au), nickel (Ni), or combinations thereof, and preferred n-contacts being made of titanium (Ti), Al, Au, Ni, or combinations thereof. The p- and n-contacts can also be deposited using know methods.
FIG. 5 shows another embodiment of a laser diode 60 according to the present invention having the same or similar layers as those shown in FIGS. 1 and 3 and described above. For those same and similar layers, the same reference numbers are used with the understanding that the description of those layers above applies to laser diode 60. The laser diode 60 has a non-conductive substrate 62 and for electrical contact to be made to the n-contact layer 64, a contact n-mesa 66 is formed by etching the layers above the n-contact layer 64. An n-contact 68 is deposited on the mesa, and when a bias is applied across the p- and n-contacts 34, 68 current from the n-contact 68 spreads into the n-contact layer 64 and to the active region 22. The ridge 32 for laser diode 60 can have the same etch depth (1-2 μm) to provide low voltage and threshold current operation.
Laser diodes according to the present invention can have other features that enhance efficiency and reliability. Referring to FIG. 5, when the ridge 32 is etched, a p-mesa 70 is formed on the sides of the ridge 32. The p-mesa 70 can have different widths, with a width being 100 μm or more. Narrower p-mesas can result in poor emission uniformity.
Following deposition of the p-contact 34, and insulating (dielectric) layer 72 can be deposited on the p-mesa 70 and exposed surfaces of the ridge 32. A bond pad 74 can then be deposited over at least part of the insulating layer 72 and in contact with the p-contact 34. The bond pad can be made of many different materials and can have many different thicknesses, with the preferred bond pad made from Au and having a minimum thickness of approximately 0.5 μm, with a preferable thickness being in the range of 1-2 μm. A wire bond 76 can be coupled to the bond pad 74 for applying an electrical signal to the bond pad and in turn to the p-contact 34. According to the present invention, the wire bond 76 should be located off of ridge 32 and preferably on the wider portion of the p-mesa 70. This location helps minimize damage to the ridge 32 during bonding of the wire bond 76.
Patent CitationsCited PatentFiling datePublication dateApplicantTitleUS4152044Jun 17, 1977May 1, 1979International Telephone And Telegraph CorporationGalium aluminum arsenide graded index waveguideUS4675575Jul 13, 1984Jun 23, 1987E & G EnterprisesLight-emitting diode assemblies and systems thereforeUS4933302Apr 19, 1989Jun 12, 1990International Business Machines CorporationFormation of laser mirror facets and integration of optoelectronicsUS5477436Jul 9, 1993Dec 19, 1995Robert Bosch GmbhIlluminating device for motor vehiclesUS5592501Sep 20, 1994Jan 7, 1997Cree Research, Inc.Low-strain laser structures with group III nitride active layersUS5838706Nov 19, 1996Nov 17, 1998Cree Research, Inc.Low-strain laser structures with group III nitride active layersUS6046464Aug 13, 1997Apr 4, 2000North Carolina State UniversityIntegrated heterostructures of group III-V nitride semiconductor materials including epitaxial ohmic contact comprising multiple quantum wellUS6330111Aug 17, 2000Dec 11, 2001Kenneth J. Myers, Edward GreenbergLighting elements including light emitting diodes, microprism sheet, reflector, and diffusing agentUS6331915Jun 13, 2000Dec 18, 2001Kenneth J. MyersLighting element including light emitting diodes, microprism sheet, reflector, and diffusing agentUS6657393Sep 18, 2001Dec 2, 2003Koito Manufacturing Co., Ltd.Vehicle lamp having light sources with LEDs arranged in two groupsUS6744800Dec 30, 1998Jun 1, 2004Xerox CorporationMethod and structure for nitride based laser diode arrays on an insulating substrateUS6746889Mar 27, 2002Jun 8, 2004Emcore CorporationOptoelectronic device with improved light extractionUS6784463Mar 11, 2002Aug 31, 2004Lumileds Lighting U.S., LlcIII-Phospide and III-Arsenide flip chip light-emitting devicesUS6825502Apr 17, 2003Nov 30, 2004Kabushiki Kaisha ToshibaLight emitting element, method of manufacturing the same, and semiconductor device having light emitting elementUS6932497Dec 17, 2003Aug 23, 2005Jean-San HuangSignal light and rear-view mirror arrangementUS6969874Jun 12, 2003Nov 29, 2005Sandia CorporationFlip-chip light emitting diode with resonant optical microcavityUS7087936Apr 6, 2004Aug 8, 2006Cree, Inc.Methods of forming light-emitting devices having an antireflective layer that has a graded index of refractionUS20020015013Jun 26, 2001Feb 7, 2002Larry RagleIntegrated color LED chipUS20020054495Sep 18, 2001May 9, 2002Koito Manufacturing Co., Ltd.Vehicle lampUS20030015708Jul 23, 2001Jan 23, 2003Primit ParikhGallium nitride based diodes with low forward voltage and low reverse current operationUS20030020069 *Jul 25, 2001Jan 30, 2003Motorola, Inc.Structure and method for optimizing transmission media through dielectric layering and doping in semiconductor structures and devices utilizing the formation of a compliant substrateUS20030085409Nov 2, 2001May 8, 2003Yu-Chen ShenIndium gallium nitride separate confinement heterostructure light emitting devicesUS20030165169 *Aug 28, 2002Sep 4, 2003Opnext Japan, Inc.Semiconductor laser diode and optical moduleUS20040207313Apr 21, 2004Oct 21, 2004Sharp Kabushiki KaishaLED device and portable telephone, digital camera and LCD apparatus using the sameUS20050077535Oct 8, 2003Apr 14, 2005Joinscan Electronics Co., LtdLED and its manufacturing processUS20050117320Sep 27, 2004Jun 2, 2005Hon Hai Precision Industry Co., Ltd.Light-emitting diode and backlight system using the sameUS20050152127Dec 16, 2004Jul 14, 2005Takayuki KamiyaLED lamp apparatusUS20050173692Jun 24, 2003Aug 11, 2005Park Young H.Vertical GaN light emitting diode and method for manufacturing the sameUS20050173728Feb 5, 2004Aug 11, 2005Saxler Adam W.Nitride heterojunction transistors having charge-transfer induced energy barriers and methods of fabricating the sameUS20060034576Aug 16, 2004Feb 16, 2006Merritt Scott ASuperluminescent diodes having high output power and reduced internal reflectionsUS20060081862Oct 14, 2004Apr 20, 2006Chua Janet B YDevice and method for emitting output light using quantum dots and non-quantum fluorescent materialUS20060158899Jan 17, 2006Jul 20, 2006Omron CorporationLuminescent light source and luminescent light source arrayUS20060220046Aug 8, 2005Oct 5, 2006Chuan-Pei YuLedUS20070025231 *Jul 28, 2006Feb 1, 2007Masanao OchiaiSemiconductor laser deviceUS20070090383Nov 30, 2006Apr 26, 2007Toyoda Gosei Co., Ltd.Light emitting deviceUS20080036364May 23, 2007Feb 14, 2008Intematix CorporationTwo-phase yellow phosphor with self-adjusting emission wavelengthUS20080074032Apr 8, 2005Mar 27, 2008Tadashi YanoMethod for Fabricating Led Illumination Light Source and Led Illumination Light SourceEP0936682A1Jul 29, 1997Aug 18, 1999Nichia Chemical Industries, Ltd.Light emitting device and display deviceEP1349202A2Mar 28, 2003Oct 1, 2003Rohm Co., Ltd.Semiconductor device and method of manufacturing the sameEP1653255A2Oct 27, 2005May 3, 2006Pentair Water Pool and Spa, Inc.Selectable beam lens for underwater lightEP1681509A1Jan 16, 2006Jul 19, 2006Omron CorporationLuminescent light source and luminescent source arrayFR2586844A1 Title not availableFR2759188A1 Title not availableFR2814220A1 Title not availableWO1998056043A1May 22, 1998Dec 10, 1998Daimlerchrysler AgSemiconductor component and method for producing the sameWO2002011212A1Jul 24, 2001Feb 7, 2002Caldus Semiconductor, Inc.W/wc/tac ohmic and rectifying contacts on sicWO2003044870A1Nov 22, 2001May 30, 2003Mireille GeorgesLight-emitting diode illuminating optical deviceWO2003080763A1Mar 21, 2003Oct 2, 2003Philips Intellectual Property & Standards GmbhTri-color white light led lampWO2005104247A1Apr 8, 2005Nov 3, 2005Matsushita Electric Industrial Co., Ltd.Method for fabricating led illumination light source and led illumination light sourceWO2007005844A2Jul 5, 2006Jan 11, 2007International Rectifier CorporationSchottky diode with improved surge capability* Cited by examinerNon-Patent CitationsReference1Asbeck et al."Enhancement of Base Conductivity Via the Piezoelectric Effect in AlGaN/GaN HBTs", Solid State Electronics, Elsevier Science Pub. Barking GB, vol. 44, No. 2, Feb. 1, 2000 pp. 211-219, XP004186190.2Canadian Patent Application No. 2,454,310, Office Action dated: Feb. 9, 2010.3European Communication from European Appl. 02 798 906.0-1235, Dated Feb. 6, 2009.4European search report for Application No. 08160129.6-2222, Dated. Dec. 15, 2009.5European Search Report from related European Application No. 07254498.4, received on Feb. 11, 2010.6European Search Report, Feb. 24, 2009, re related European Application No. EP 08253301.7Examiner's Report to the Board (Summary) from Japanese Patent Application No. 2003-529535, Appeal Filing Number: 2009-007421 dated Dec. 7, 2010.8International Search Report for PCT/US2008/004453, Date: Sep. 9, 2008.9Invitation to Submit Applicant's Opinion (Summary) from Japanese Patent Application No. 2003-529535, Appeal Filing Number: 2009-007421 dated Dec. 7, 2010.10Johnson et al."New UV Light Emitter Based on AlGaN Heterostructures with Graded Electron and Hole Injectors", Materials Research Society Symposium-Proceedings 2002 Materials Research Society US, vol. 743, 2002, pp. 481-486.11Johnson et al."New UV Light Emitter Based on AlGaN Heterostructures with Graded Electron and Hole Injectors", Materials Research Society Symposium—Proceedings 2002 Materials Research Society US, vol. 743, 2002, pp. 481-486.12Kim J K et al. "Strongly Enhanced Phosphor Efficiency in GaInN White Light-Emitting Diodes Using Remote Phosphor Configuration and Diffuse Reflector Cup", Japanese Journal of Applied Physics, Japan Society of Applied Physics, Tokyo, JP, vol. 44, No. 20-23, Jan. 1, 2005, XP-001236966.13Notice of Allowance from related U.S. Appl. No. 11/600,617, dated: Jun. 11, 2010.14Notice of First Office Action from China Patent Application No. 200710142217.6, dated: Jun. 22, 2009.15Notice Requesting Submission of Opinion re related Korean Application No. 10-2004-7001033, dated: Mar. 9, 2009.16Office Action from related U.S. Appl. No. 11/600,617, dated: Dec. 19, 2008.17Office Action from related U.S. Appl. No. 11/600,617, dated: Dec. 22, 2009.18Office Action from related U.S. Appl. No. 11/600,617, dated: Feb. 14, 2008.19Office Action from related U.S. Appl. No. 11/600,617, dated: Jul. 8, 2009.20Office Action from related U.S. Appl. No. 11/600,617, dated: Jun. 11, 2008.21Office Action from related U.S. Appl. No. 11/600,617, dated: Oct. 20, 2009.22Office Action from U.S. Appl. No. 11/600,618, dated: Feb. 4, 2010.23Official Communication from the EPO regarding European Application 08253301.9, dated: Nov. 17, 2009.24Official Notice of Final Decision of Rejection re Japanese Patent Appl. No. 2003-529535, Dated: Jan. 6, 2009.25PCT Search Report and Written Opinion PCT/US2007/086237, date: May 8, 2008 in related application.26PCT Search Report and Written Opinion PCT/US2007/086242, Date: Mar. 4, 2008.27PCT Search Report and Written Opinion PCT/US2007/12403, Date: Aug. 6, 2008.28Response to Office Action from related U.S. Appl. No. 11/600,617, dated; Mar. 14, 2008.29Response to Office Action from related U.S. Appl. No. 11/600,617, dated; Mar. 18, 2009.30Response to Office Action from related U.S. Appl. No. 11/600,617, dated; Mar. 18, 2010.31Response to Office Action from related U.S. Appl. No. 11/600,617, dated; Nov. 3, 2009.32Response to Office Action from related U.S. Appl. No. 11/600,617, dated; Sep. 12, 2008.33Response to Office Action from related U.S. Appl. No. 11/600,617, dated; Sep. 2, 2009.34Sakai et al., "Experimental Investigation of Dependence of Electrical Characteristics on Device Parameters in Trench MOS Barrier Shottky Diodes", Proceedings of 1998 International Symposium on Power Semiconductor Devices & ICs, Kyoto, pp. 293-296, Jun. 1998.35Second Office Action from Chinese Application No. 200710142217.6, dated: Nov. 6, 2009.36Second Office Action from People's Republic of China, re China Application No. 200480027969.2, dated; Jul. 4, 2008.37Simon et al. "Polarization-Induced 3-Dimensional Electron Slabs in Graded AlGaN Layers", Materials Research Society Symposium Proceedings 2006 Materials Research Society US, vol. 892, Nov. 28, 2005, pp. 417-422.38U.S. Appl. No. 11/613,692, filed Dec. 20, 2006.39U.S. Appl. No. 11/614,180, filed Dec. 21, 2006.40U.S. Appl. No. 11/624,811, filed Jan. 19, 2007.41U.S. Appl. No. 11/736,799, filed Apr. 18, 2007.42U.S. Appl. No. 11/743,754, filed May 3, 2007.43U.S. Appl. No. 11/751,982, filed May 22, 2007.44U.S. Appl. No. 11/751,990, filed May 22, 2007.45U.S. Appl. No. 11/753,103, filed May 24, 2007.46U.S. Appl. No. 11/755,153, filed May 30, 2007.47U.S. Appl. No. 11/818,818, filed Jun. 14, 2007.48U.S. Appl. No. 11/843,243, filed Aug. 22, 2007.49U.S. Appl. No. 11/856,421, filed Sep. 17, 2007.50U.S. Appl. No. 11/859,048, filed Sep. 21, 2007.51U.S. Appl. No. 11/870,679, filed Oct. 11, 2007.52U.S. Appl. No. 11/877,038, filed Oct. 23, 2007.53U.S. Appl. No. 11/936,163, filed Nov. 7, 2007.54U.S. Appl. No. 11/939,047, filed Nov. 13, 2007.55U.S. Appl. No. 11/939,052, filed Nov. 13, 2007.56U.S. Appl. No. 11/948,041, filed Nov. 30, 2007.57U.S. Appl. No. 11/949,222, filed Dec. 3, 2007.58U.S. Appl. No. 12/002,429, filed Dec. 4, 2007.59U.S. Appl. No. 12/045,729, filed Mar. 11, 2008.60U.S. Appl. No. 12/174,053, filed Jul. 16, 2008.61U.S. Copending U.S. Appl. No. 11/443,741, filed Jun. 14, 2007.62U.S. Copending U.S. Appl. No. 11/685,761, filed Mar. 13, 2007.63U.S. Copending U.S. Appl. No. 11/939,059, filed Nov. 13, 2007.64Written Opinion for PCT/US2008/004453, Date: Sep. 9, 2008.65Zhang AP et al, "Comparison of GAN P-I-N and Schottky Rectifier Performance" IEEE Transactions on Electron Devices, IEEE Inc. New York, US, vol. 48, No. 3, pp. 407-411, Mar. 2001.Referenced byCiting PatentFiling datePublication dateApplicantTitleUS8358673 *Feb 17, 2011Jan 22, 2013Corning IncorporatedStrain balanced laser diodeUS20120213240 *Feb 17, 2011Aug 23, 2012Rajaram BhatStrain balanced laser diode* Cited by examinerClassifications U.S. Classification372/45.011, 372/43.01, 372/45.012, 428/670, 428/25International ClassificationH01S5/00, H04B10/00Cooperative ClassificationH01S5/2009, H01S5/3063, H01S5/3216, H01S5/2081, H01S5/22, Y10T428/12875, H01S5/34333, H01S5/0021, B82Y20/00, H01S5/0202, H01S2304/00European ClassificationH01S5/343G, B82Y20/00Legal EventsDateCodeEventDescriptionApr 15, 2015FPAYFee paymentYear of fee payment: 4RotateOriginal ImageGoogle Home - Sitemap - USPTO Bulk Downloads - Privacy Policy - Terms of Service - About Google Patents - Send FeedbackData provided by IFI CLAIMS Patent Services