WO2008060531A2 - Diode électroluminescente et diode laser dans lesquelles sont utilisés du gan, du inn et du aln et leurs alliages face azote - Google Patents

Diode électroluminescente et diode laser dans lesquelles sont utilisés du gan, du inn et du aln et leurs alliages face azote Download PDF

Info

Publication number
WO2008060531A2
WO2008060531A2 PCT/US2007/023828 US2007023828W WO2008060531A2 WO 2008060531 A2 WO2008060531 A2 WO 2008060531A2 US 2007023828 W US2007023828 W US 2007023828W WO 2008060531 A2 WO2008060531 A2 WO 2008060531A2
Authority
WO
WIPO (PCT)
Prior art keywords
nitride
face
type
layer
active region
Prior art date
Application number
PCT/US2007/023828
Other languages
English (en)
Other versions
WO2008060531A3 (fr
WO2008060531A9 (fr
Inventor
Nicholas A. Fichtenbaum
Umesh K. Mishra
Stacia Keller
Original Assignee
The Regents Of The University Of California
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 The Regents Of The University Of California filed Critical The Regents Of The University Of California
Priority to JP2009537185A priority Critical patent/JP2010510655A/ja
Publication of WO2008060531A2 publication Critical patent/WO2008060531A2/fr
Publication of WO2008060531A3 publication Critical patent/WO2008060531A3/fr
Publication of WO2008060531A9 publication Critical patent/WO2008060531A9/fr

Links

Classifications

    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L33/00—Semiconductor devices having potential barriers specially adapted for light emission; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof
    • H01L33/02—Semiconductor devices having potential barriers specially adapted for light emission; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof characterised by the semiconductor bodies
    • H01L33/04—Semiconductor devices having potential barriers specially adapted for light emission; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof characterised by the semiconductor bodies with a quantum effect structure or superlattice, e.g. tunnel junction
    • H01L33/06—Semiconductor devices having potential barriers specially adapted for light emission; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof characterised by the semiconductor bodies with a quantum effect structure or superlattice, e.g. tunnel junction within the light emitting region, e.g. quantum confinement structure or tunnel barrier
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B82—NANOTECHNOLOGY
    • B82Y—SPECIFIC USES OR APPLICATIONS OF NANOSTRUCTURES; MEASUREMENT OR ANALYSIS OF NANOSTRUCTURES; MANUFACTURE OR TREATMENT OF NANOSTRUCTURES
    • B82Y20/00—Nanooptics, e.g. quantum optics or photonic crystals
    • 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
    • H01S5/3202—Structure or shape of the active region; Materials used for the active region comprising PN junctions, e.g. hetero- or double- heterostructures grown on specifically orientated substrates, or using orientation dependent growth
    • H01S5/320225—Structure or shape of the active region; Materials used for the active region comprising PN junctions, e.g. hetero- or double- heterostructures grown on specifically orientated substrates, or using orientation dependent growth polar orientation
    • 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
    • H01S5/34—Structure or shape of the active region; Materials used for the active region comprising quantum well or superlattice structures, e.g. single quantum well [SQW] lasers, multiple quantum well [MQW] lasers or graded index separate confinement heterostructure [GRINSCH] lasers
    • H01S5/343—Structure or shape of the active region; Materials used for the active region comprising quantum well or superlattice structures, e.g. single quantum well [SQW] lasers, multiple quantum well [MQW] lasers or graded index separate confinement heterostructure [GRINSCH] lasers in AIIIBV compounds, e.g. AlGaAs-laser, InP-based laser
    • H01S5/34333—Structure or shape of the active region; Materials used for the active region comprising quantum well or superlattice structures, e.g. single quantum well [SQW] lasers, multiple quantum well [MQW] lasers or graded index separate confinement heterostructure [GRINSCH] lasers in AIIIBV compounds, e.g. AlGaAs-laser, InP-based laser with a well layer based on Ga(In)N or Ga(In)P, e.g. blue laser
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L33/00—Semiconductor devices having potential barriers specially adapted for light emission; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof
    • H01L33/02—Semiconductor devices having potential barriers specially adapted for light emission; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof characterised by the semiconductor bodies
    • H01L33/16—Semiconductor devices having potential barriers specially adapted for light emission; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof characterised by the semiconductor bodies with a particular crystal structure or orientation, e.g. polycrystalline, amorphous or porous
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L33/00—Semiconductor devices having potential barriers specially adapted for light emission; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof
    • H01L33/02—Semiconductor devices having potential barriers specially adapted for light emission; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof characterised by the semiconductor bodies
    • H01L33/26—Materials of the light emitting region
    • H01L33/30—Materials of the light emitting region containing only elements of Group III and Group V of the Periodic Table
    • H01L33/32—Materials of the light emitting region containing only elements of Group III and Group V of the Periodic Table containing nitrogen

Definitions

  • This invention is related to growth of Group III nitride materials, and in particular to Light Emitting Diodes (LEDs) and Laser Diodes (LDs) made from Nitrogen (N) face Gallium Nitride (GaN) Indium Nitride (InN), and Aluminum Nitride (AlN) and their alloys.
  • LEDs Light Emitting Diodes
  • LDs Laser Diodes
  • the present invention describes light emitting diodes (LEDs) and Laser Diodes (LDs) with improved properties using N-face group III nitride materials.
  • a light emitting device in accordance with the present invention comprises a p-type group-Ill nitride,an n-type group-Ill nitride, and a group-III-nitride active region growth along a [000-1] crystal direction resulting in a top surface which is a nitrogen face, wherein a first grown layer of the group Ill-nitride active region growth is a group III atom layer and a last grown layer of the Ill-nitride active region growth is a nitrogen layer, such that a spontaneous polarization points towards a growth surface of the Ill-nitride active region; and the Ill-nitride active region growth is light emitting and between the n-type nitride and the p-type nitride.
  • Such a device further optionally comprises the Ill-nitride active region growth is from a nitrogen face, the Ill-nitride active region growth is from a group-III-nitride layer, the Ill-nitride active region is on a misoriented and nitridized substrate, the III- nitride active region growth is a growth from the n-type nitride, the n-type nitride is a growth along a [000-1] direction resulting in a top surface of the n-type nitride which is an N- face, the p-type nitride is a growth from the N- face of the Ill-nitride active region, the p-type nitride has a magnesium doping greater than 3x10 20 , the active region contains indium, the Ill-nitride active region growth contains more indium than an active region which is a growth along a [0001] direction resulting in a top surface which is a
  • a method for growing a light emitting device in accordance with the present invention comprises growing a light emitting Ill-nitride active region along a [000-1] crystal direction, resulting in a top surface of the Ill-nitride active region which is nitrogen-face (N-face).
  • Such a method further optionally comprises the light emitting Ill-nitride active region contains indium and is grown at a higher temperature and has an improved surface quality compared to an active region grown along a [0001] direction, growing an n-type nitride along a [000-1] direction and terminating on an N-face of the n-type nitride layer, growing the light emitting Ill-nitride active region on the N-face of the n-type nitride layer; and growing a p-type nitride layer along a [000-1] direction on the N-face of the light emitting Ill-nitride active region and terminating on an N-face of the p-type nitride layer, growing an n-type N-face GaN buffer layer on a misoriented and nitridized substrate;growing the light emitting Ill-nitride active region on the n-type N-face GaN buffer layer, the light emitting III- nitride active
  • the method can further optionally comprise growing an n-type N-face AlGaN buffer and confinement layer, growing an n-type N-face GaN layer on the AlGaN buffer and confinement layer, growing the light emitting Ill-nitride active region on the n-type N-face GaN layer, the light emitting Ill-nitride active region comprising multiple quantum wells of InGaN active material, growing a p-type N-face GaN layer on the light emitting Ill-nitride active region, growing a p-type AlGaN cladding layer on the p-type N-face GaN layer, applying a metal to contact the p-type AlGaN cladding layer, etching a laser diode stripe structure and forming mirror facets into the layers obtained from the above steps, and applying a second metal to contact the n- type N-face GaN layer.
  • a Ill-nitride film in accordance with the present invention comprises a growth of Ill-nitride resulting in a top surface which is a nitrogen face.
  • Such a film further optionally comprises a first grown layer of the growth is a group III atom layer and a last grown layer of the growth is a nitrogen layer, such that a spontaneous polarization points towards a growth surface of the Ill-nitride film, the growth is from a misoriented and nitridized surface of a substrate, and the Ill-nitride film emits light.
  • FIG. 1 illustrates charge profiles for (a) Ga-face and (b) N-face P-I-N structures;
  • FIG. 2 illustrates band diagrams for Ga-face and N-face multiple quantum well LEDs
  • FIG. 3 illustrates a typical LED epitaxial structure
  • FIG. 4 illustrates a typical LD epitaxial structure
  • FIG. 5 illustrates an LED growth structure and band diagram
  • FIG. 6 is a process chart illustrating the process used in fabricating the LED of FIG. 5
  • FIG. 7 is a process chart illustrating the process used in an embodiment of the present invention
  • FIG. 8 is a process chart illustrating the process used in an embodiment of the present invention.
  • FIG. 9 is an AFM image of a N- face surface of a GaN film grown by MBE on
  • FIG. 10(a) shows an optical microscope image
  • FIG. 10(b) shows an AFM image, of an MOCVD grown GaN N- face film.
  • FIG. 11 shows an optical image of a prior art N-face Ill-nitride.
  • FIG. 12 is an AFM image and photoluminescence data for N-face Hi-nitride of the present invention.
  • the present invention allows the growth of InGaN with greater compositions of Indium than traditionally available now, which pushes LED and LD wavelengths into the yellow and red portions of the color spectrum.
  • the ability to grow with Indium at higher temperatures leads to a higher quality AlInGaN.
  • This also allows for novel polarization-based band structure designs to create more efficient devices. Additionally, it allows the fabrication of p-GaN layers with increased conductivity, which improves device performance.
  • the present invention allows for the creation of high brightness LEDs and LDs with improved properties.
  • N-face based devices enables the growth of better quality, high Indium composition InGaN alloys which are currently needed to create high power devices in the green, yellow, and red parts of the color spectrum.
  • Ga-face GaN suffers from inversion, while N-face doesn't, when doped highly with Mg (e.g., Mg concentrations of approximately 3 x 10 20 which is needed to create p-type GaN). Since high p-type carrier concentrations are a major limitation in nitride based devices, the use of the N-face will drastically increase device performance.
  • Ill-Nitrides The wurtzite structure of Ill-Nitrides causes Ill-Nitrides to exhibit large spontaneous and piezoelectric fields oriented about the [0001] axis. Due to differences in polarization constants, large fixed polarization charges exist at heterostructure interfaces and subsequently electric fields are formed. The direction of these polarization charges and subsequent electric field depends upon the growth direction ([0001] or [000-1]) of the epitaxial film. In the traditional Ga-face LEDs and LDs, the magnitude of the electric field in the quantum well is positive, while in N-face the electric field is negative.
  • the growth substrate typically has a growth surface with a misorientation angle between 0.5 and 10 degrees in any direction relative to a miller indexed crystallographic plane [h, i, k, 1] of the substrate, where h, i, k, 1 are miller indices; and growing the N-face group Ill-nitride film on the growth surface, wherein the group Ill-nitride film having an N-face is smoother than an N-face group III- nitride film grown on a substrate without a misorientation angle.
  • the misoriented/viscinal substrate is typically nitridized at medium temperature (approximately 1050° C).
  • the nitridization leads to the formation of an AlN nucleation layer (one or more monolayers thick, for example) on the surface of the sapphire, which sets the N-face polarity of the growth.
  • the nitridization breaks the surface layers of sapphire into AlN.
  • Growth of N-face Ill-nitride buffer or template can then commence on the AlN nucleation layer(s) terminating the substrate.
  • Growth of Ill-nitride on a nitridized misoriented/viscinal substrate at high temperature allows a group III atomic layer to be deposited first and a nitrogen atom layer to be deposited last, yielding an N-face for the Ill-nitride layer. Subsequent layers grown on the N-face of the first grown Ill-nitride layer will also be N-face.
  • the underlying surface on which Ill-Nitride is grown doesn't have to be an N- face to allow the Ga atoms to bond first, it just has to be more attractive (either electrically or mechanically, or both) to the Ga atoms than the N atoms.
  • the N-face is grown last (or formed last) because the Ga-atoms bond better to the nitridized substrate/N-face of the previously-grown layers, which results in a final face of the wurtzite crystal growth being an N-face.
  • the above discussion also holds if the Ga atoms are group III atoms. Further, the definition of N-face or Ga- face is not usually defined by the stacking order (i.e Ga then N or N then Ga).
  • the N-face is better defined by the atomic arrangements of the Ga — N bonds, which is encompassed in the direction of the spontaneous polarization of the material.
  • the spontaneous polarization points towards the surface, while the spontaneous polarization in Ga-face points away from the surface.
  • N-face may refer either to the spontaneous polarization pointing to the suface or the N-atoms residing in the upper layer.
  • the Ill-nitride is deposited at medium/high growth temperatures (-1050 0 C- or more typically between 800 - 1100 C, depending upon the reactor. More details can be found in U.S Utility Patent Application Serial No. 11/855,591, entitled "METHOD FOR HETEROEPIT AXIAL GROWTH OF HIGH-QUALITY N-FACE GaN, InN, and AlN AND THEIR ALLOYS BY METAL ORGANIC CHEMICAL VAPOR DEPOSITION, filed September 14, 2007, which application is incorporated by reference herein.
  • FIG. 11/855,591 entitled "METHOD FOR HETEROEPIT AXIAL GROWTH OF HIGH-QUALITY N-FACE GaN, InN, and AlN AND THEIR ALLOYS BY METAL ORGANIC CHEMICAL VAPOR DEPOSITION, filed September 14, 2007, which application is incorporated by reference herein.
  • FIG. l(a) is a schematic showing a PIN structure 100 made from Ga-Face material, comprising a stack of p-type material 102, intrinsic InGaN material 104, and n-type material 106.
  • the graph 108 also shows the polarization (P TOT ) at the interface between the p-type material 102 and intrinsic InGaN material 104 is positive and P TOT at the interface between the n-type material 106 and intrinsic material 104 is negative.
  • FIG. l(b) is a schematic showing a PIN structure 112 made from N-Face material, comprising a stack of p-type material 114, intrinsic InGaN material 116, and n-type material 118.
  • the graph 120 also shows the P T O T at the interface between the p-type material 114 and intrinsic material 116 is negative and P TOT at the interface between the n-type material 118 and intrinsic InGaN material 116 is positive.
  • the band energy 200,202 in the active region 206 increases from the interface 210 with the p-type material towards the interface 212 with the n-type material (positive gradient), meaning that the electric field in the active region is positive.
  • the band energy 214, 216 in the active region 220 decreases from the interface 224 (with the p-type material) towards the interface 226 (with the n-type material), meaning the electric field in the active region 220 is negative.
  • FIGs. 2(a) and 2(b) also show a decreased depletion width at the interfaces 224, 226 (and consequently decreased turn on voltage for N- face grown GaN devices as compared to Ga-face grown GaN).
  • the decreased depletion width is evidenced by the more abrupt (vertical) band 228 gradient for the N-face grown GaN as compared to the less abrupt (lower) band gradient Ga-face grown GaN 230.
  • N-face LEDs and LDs While the production of Ga-face LEDs and LDs in the Ill-Nitride system is widely reported by companies and also universities, growth of a N-face LED or LD has not yet been reported. In the past, growth of N-face by metalorganic chemical vapor deposition lagged significantly behind Ga-face growth in crystal quality, which is the likely reason that there are not reports of light emitters. N-face growth of Ill- Nitrides has been successfully achieved by molecular beam epitaxy (MBE), however the optical quality of the material is still poor, i.e., the efficiency of the device is far less than state of the art Ga-face devices. Currently, the performance of LEDs in the yellow and red part of the spectrum is poor, while laser diodes emitting in the green have not been achieved.
  • MBE molecular beam epitaxy
  • the LED aspect of this invention is realized by: 1) Growth (typical structure shown in FIG. 3): a) Growth of a n-type N-face GaN buffer layer 300 on a substrate 302. b) An optional AlGaN hole blocking layer can be added. c) The active region is then typically grown, which will comprise of multiple quantum wells of InGaN active material. The quantum wells comprise InGaN 304 and GaN 305 material. d) An optional AlGaN current blocking layer can then be added. e) Growth of a p-type N- face GaN cap layer 306.
  • the arrow 308 indicates the growth direction [000-1], such that the final growth surface 310 of each layer 300-306 is an N- face, and the first growth surface 312 of each layer 300, 304, and 306 is a Ga face or group III atom face.
  • a first grown layer of the Ill-nitride active region growth, n-type nitride, and p-type nitride is a group III atom layer and a last grown layer of the Ill-nitride active region, n-type nitride, or p-type nitride growth is a nitrogen layer.
  • the surface 310 is Ga face (or a face of group III material) and the surface 312 is N-face.
  • growth of group Ill-nitride material comprises alternating layers of group III atoms and nitrogen atoms, with equal numbers of group III layers and nitrogen layers.
  • a GaN layer comprises equal numbers one or more Ga layers alternating with the same number of nitrogen layers, or again, has a spontaneous polarization pointing toward the surface for the N- faces and a spontaneous polarization pointing away from the surface for the Ga- faces.
  • the LD aspect of this invention is realized by: 1) Growth (typical structure shown in FIG. 4): a) n-type N-face AlGaN buffer and confinement layer 400 on a substrate 402. b) N-type N-face GaN layer 404. c) Active region 406 comprising multiple quantum wells of InGaN active material. d) P-type N-face GaN layer 408. e) P-type AlGaN cladding layer 410. 2) Processing: a) An appropriate metal is applied to contact the p-type layer 410 b) LD stripe structure and mirror facets are etched. c) An appropriate metal is applied to contact the n-type layer 400.
  • MOCVD MOCVD
  • HVPE HVPE
  • CBE CBE
  • FIG. 5(a) illustrates a schematic of a growth structure of an N-face LED with tunnel junction.
  • the LED comprises an Si doped GaN layer 500, an InGaN/GaN multi quantum well active region 502, an Mg doped GaN layer 504, an AlN layer 506 and an Si doped GaN layer 508.
  • the AlN layer 506 forms a tunnel junction between the GaN layers 504 and 508.
  • the arrow 510 in FIG. 5(a) shows the growth direction and the orientation of the N-face surface, and therefore indicates that the last growth surface of each layer 500-508 is an N-face surface 512.
  • the first growth surface of each layer is therefore a Ga surface (or group III atom surface) 514.
  • the surface 512 is a Ga face and the surface 514 is an N-face.
  • the band diagram plots the conduction band energy Ec 518 and the valence band energy Ey 520.
  • the band diagram shows Ec ⁇ 0 522 in the n-type layers 500, 508, evidencing all n-type contact to the LED.
  • the all n-type contacts are possible due to the polarization induced tunnel junction whose energy is also shown in FIG. 5(b).
  • the large gradient of the band profile 524 at the interface between the active region 502 and the p-type layer 504 evidences a narrow depletion region.
  • E v ⁇ 0 526 in the thin p-type layer 504 evidences reduced series resistance for the device.
  • FIGS. 6(a)-(e) illustrate a method of fabricating an N- face LED with tunnel junction.
  • FIG. 6(a) illustrates the step of preparing the surface of the sapphire substrate, for example, pre-patterning a sapphire substrate by a dry etch to form a patterned sapphire surface (PSS) 600.
  • PSS patterned sapphire surface
  • FIG. 6(b) illustrates the step of growing the layers 500-508 sequentially in the N-face direction 602.
  • FIG. 6(c) illustrates the step of etching a mesa using a reactive ion etch (RIE) etch.
  • FIG. 6(d) illustrates the step of wet etching the Si doped GaN layer 508 (the base of the LED) in order to roughen the top surface 604 of the Si GaN layer 508. The roughened surface 604 enhances light extraction from the LED.
  • RIE reactive ion etch
  • FIG. 6(e) illustrates the step of forming n-type ohmic contacts 606 on the layers 508 and 500.
  • Any appropriate substrate can be used, such as SiC, Si, spinel, bulk GaN, ZnO, etc., as long as N-face GaN can be grown.
  • the epitaxial structure described with InGaN as the active material and also the corresponding confinement and buffer layers can be changed to use GaN, AlGaN, or AlInGaN- depending upon the desired wavelength of emission.
  • the structure can be grown with p-type first followed by an active region and n-type as long as the polarity is still N-face.
  • the layer thicknesses and compositions can be varied appropriately.
  • the LD can be grown appropriately to create a vertical cavity surface emitting laser (VCSEL) with the addition of distributed Bragg reflectors (DBR) above and below the active region.
  • VCSEL vertical cavity surface emitting laser
  • DBR distributed Bragg reflectors
  • the LED structure can be grown upon a DBR to enhance light extraction.
  • Light extraction methods can be applied to the LED such as ZnO megacones or surface roughening.
  • Ga- face growth throughout this disclosure also applies to group III atom growth along the [0001] direction.
  • the present invention describes a light emitting device, comprising p-type nitride, n-type nitride, and an active region between the p-type nitride and the n-type nitride, wherein the active region is a growth of nitride along a [000-1] crystal direction terminating with a nitrogen face.
  • the p-type layer, n-type layer, and active layer may have any composition or structure known in the art suitable for use in a III- nitride (or Ill-nitride alloy comprising (Al, In, Ga)N, for example) based light emitting diode or laser diode. Therefore, the active layer is not limited to quantum wells.
  • additional layers as are known in the art may also be included, for example, current spreading layers, contacts layers etc.
  • FIG. 7 is a process chart illustrating the process used in an embodiment of the present invention.
  • a typical process chart is as follows.
  • Box 700 illustrates growing a n-type N-face GaN buffer layer on a substrate.
  • Box 702 illustrates growing an active region, the active region comprising a multiple quantum well region.
  • Box 704 illustrates growing a p-type N-face GaN cap layer.
  • Box 706 illustrates applying a metal to contact the p-type layer.
  • Box 708 illustrates forming LED mesas by etching.
  • Box 710 illustrates applying a second metal to contact the n-type layers.
  • Box 800 illustrates growing a N-type N-face AlGaN buffer and confinement layer on a substrate.
  • Box 802 illustrates growing an N-type N-face GaN layer.
  • Box 804 illustrates growing an active region comprising multiple quantum wells of InGaN active material.
  • Box 806 illustrates growing a P-type N-face GaN layer.
  • Box 808 illustrates growing a P-type AlGaN cladding layer.
  • Box 810 illustrates applying a metal to contact the p-type layer.
  • Box 812 illustrates etching an LD stripe structure and mirror facets.
  • Box 814 illustrates applying a second metal to contact the n-type layer.
  • the various layers are grown at temperatures appropriate to control the desired alloy composition of the particular layer.
  • the present invention also allows the growth of Ill-nitride N-face films.
  • the films can be grown using a variety of growth methods, including but not limited to Molecular Beam Epitaxy (MBE) and Metal Organic Chemical Vapor Deposition (MOCVD).
  • FIG. 9 shows N-face surface AFM image of a GaN film grown by MBE on C-face SiC.
  • the growth temperature was 710-720°C, and the dislocation reduction was achieved using a two step buffer, wherein in step 1 GaN growth was initiated on the SiC with a Ga flux in a low to intermediate regime and in step 2 morphology was recovered by increasing the Ga flux.
  • This method achieved a threading dislocation density of ⁇ 10 10 cm “2 , and a surface roughness of at most 5 nm in a 5 micron by 5 micron area.
  • the film was doped with Si to at least 3 x 10 18 cm “3 to achieve a mobility of at least 140 cm 2 /Vs, which is comparable to Ga- face MBE grown films.
  • N-face p-type films have increased surface stability when they are doped with high (> 1x10 20 ) Mg concentrations. These films could be used as substrates or devices, such as electronic (transistors) or optoelectronic devices.
  • FIG. 10(a) shows an optical microscope image
  • FIG. 10(b) shows an AFM image, of an MOCVD grown GaN N-face film, showing rms roughness of at most 0.9 nm.
  • XRD measurements of these 1-1.5 micron thick GaN films measured FWHM (along the 002 reflection) of at most 110 arcsecs and FWHM (along the 201 reflection) of at most 900 arcsecs for a misorientation of 2 degrees towards the sapphire A direction, and FWHM (along the 002 reflection) of at most 300 arcsecs and FWHM (along the 201 reflection) of at most 450 arcsecs for a misoreintation of four degrees toward the sapphire A direction.
  • FIG. 11 shows the poor surface morphology of prior art N-face growth.
  • prior art growth by MOCVD has been typically rough due to formation of hexagonal hillocks (having micron sized dimensions), observed for hetero-epitaxial and homoepitaxial growth of GaN. This poor surface morphology has prevented application for devices.
  • FIG. 12(a) shows an AFM image of InGaN/GaN multi quantum wells (MQWs) grown using the present invention, where the RMS roughness is 0.85 nm, showing a smooth surface at InGaN growth temperatures.
  • FIG. 12(b) shows 300 Kelvin photoluminescence (PL) of MQWs comprising 5 x (3 nm thick In 0 1 Ga O 9 N/ 8 nm thick GaN), grown by MOCVD according to the present invention. The photoluminescence is intense in the range 385 nm to 475 nm.
  • PL Kelvin photoluminescence
  • the N-face Ill-nitride grown using the present invention has increased optical quality and increased structural or surface quality.
  • the increased structural or surface quality characterized by reduced surface roughness, smaller XRD diffraction FWHM's, reduced threading dislocation), as compared to N-face Ill-nitride grown using prior art techniques.
  • the increased optical quality is evidenced by the fact that prior art methods have not achieved adequate light emission whereas the present invention has higher emission efficiency in these regions.
  • N-face allows the growth of InGaN at higher temperatures than the traditional Ga-face, which will provide better quality material as well as making higher indium content films feasible, where indium content films are now more stable at any concentration of indium in the InGaN material.
  • the growth temperature for MBE grown InN is approximately 100 0 C higher for N- face growth as compared to Ga-face growth.
  • p-type doping Another challenge to the growth of light emitters is p-type doping.
  • Mg p-type doping
  • N- face does not seem to suffer a similar fate with p-type doping, allowing higher levels of p-type doping, which will create much better device performance.
  • N- face material provides an electric field in the opposite direction to the traditional Ga-face which allows for lower turn-on voltages and also increased quantum efficiencies.
  • N-face The etching properties of N-face are distinctly different from that of Ga-face which will be useful in creating better light extraction schemes in LEDs, such as surface roughening, and mega-cones.
  • N-face devices can be obtained by growing a nitride device in the Ga (0001) direction and removing the substrate to expose the N-Face of the device.
  • this process is more difficult (and consequently more expensive and time consuming) than the present invention because it involves the additional step of substrate removal.
  • the present invention grows a light emitting device on a misoriented or miscut substrate.
  • the miscut shows in subsequent layers grown on the miscut substrate.
  • the misorientation is transferred to layers grown on top of the buffer layer, all of which can be measured by x-ray diffraction.
  • the active region in a device grown using the present invention will typically have a higher oxygen concentration as compared to the active region grown in a Ga-polar (0001) direction.
  • the present invention may grow the p-type layer before or after the n-type layer and active layer.
  • the p-type layer would have to be grown before the n-type layer and active layer.
  • the order in which the layers have been grown can also be measured by measuring impurity concentrations and structural quality of the various layers. Growing a p-type layer first generally leads to poor material on top because of the use of high Mg doping concentrations, which creates defects.
  • Homo-epitaxial GaN growth on exact and misoriented single crystals suppression of hillock formation: A.R.A. Zauner, J.L. Weyher, M. Plomp, V. Kirilyuk, I. Grzegory, W.J.P. van Enckevort, JJ. Schermer, P.R. Hageman, and P.K. Larsen, J. Cryst. Growth 210 (2000) 435 - 443.
  • Homo-epitaxial GaN growth on the N- face of GaN single crystals the influence of the misorientation on the surface morphology: A.R.A. Zauner, A. Aret, W.J.P. van Enckevort, J.L. Weyher , S. Porowski, JJ. Schermer, J. Cryst. Growth 240 (2002) 14 - 21.
  • N-polarity GaN on sapphire substrates grown by MOCVD T. Matsuoka, Y. Kobayashi, H. Takahata, T. Mitate, S Mizuno, A. Sasaki, M. Yoshimoto, T. Ohnishi, and M. Sumiya, phys. stat. sol. (b) 243 (2006) 1446 - 1450.
  • RF-MBE Naoi et al., J. Cryst. Growth 269 (2004) 155-161.
  • the present invention describes Ill-nitride films, light emitting devices and methods for making light emitting devices and Ill-nitride films.
  • a light emitting device in accordance with the present invention comprises a p-type group-Ill nitride,an n-type group-Ill nitride, and a group-III-nitride active region growth along a [000-1] crystal direction resulting in a top surface which is a nitrogen face, wherein a first grown layer of the group Ill-nitride active region growth is a group III atom layer and a last grown layer of the Ill-nitride active region growth is a nitrogen layer, such that a spontaneous polarization points towards a growth surface of the Ill-nitride active region; and the Ill-nitride active region growth is light emitting and between the n-type nitride and the p-type nitride.
  • Such a device further optionally comprises the Ill-nitride active region growth is from a nitrogen face, the Ill-nitride active region growth is from a group-III-nitride layer, the Ill-nitride active region is on a misoriented and nitridized substrate, the III- nitride active region growth is a growth from the n-type nitride, the n-type nitride is a growth along a [000-1] direction resulting in a top surface of the n-type nitride which is an N- face, the p-type nitride is a growth from the N-face of the Ill-nitride active region, the p-type nitride has a magnesium doping greater than 3x10 20 , the active region contains indium, the Ill-nitride active region growth contains more indium than an active region which is a growth along a [0001] direction resulting in a top surface which is a
  • a method for growing a light emitting device in accordance with the present invention comprises growing a light emitting Ill-nitride active region along a [000-1] crystal direction, resulting in a top surface of the Ill-nitride active region which is nitrogen-face (N-face).
  • Such a method further optionally comprises the light emitting Ill-nitride active region contains indium and is grown at a higher temperature and has an improved surface quality compared to an active region grown along a [0001] direction, growing an n-type nitride along a [000-1] direction and terminating on an N-face of the n-type nitride layer, growing the light emitting Ill-nitride active region on the N-face of the n-type nitride layer; and growing a p-type nitride layer along a [000-1] direction on the N-face of the light emitting Ill-nitride active region and terminating on an N-face of the p-type nitride layer, growing an n-type N-face GaN buffer layer on a misoriented and nitridized substrate;growing the light emitting Ill-nitride active region on the n-type N-face GaN buffer layer, the light emitting III- nitride active
  • the method can further optionally comprise growing an n-type N-face AlGaN buffer and confinement layer, growing an n-type N-face GaN layer on the AlGaN buffer and confinement layer, growing the light emitting Ill-nitride active region on the n-type N-face GaN layer, the light emitting Ill-nitride active region comprising multiple quantum wells of InGaN active material, growing a p-type N-face GaN layer on the light emitting Ill-nitride active region, growing a p-type AlGaN cladding layer on the p-type N-face GaN layer, applying a metal to contact the p-type AlGaN cladding layer, etching a laser diode stripe structure and forming mirror facets into the layers obtained from the above steps, and applying a second metal to contact the n- type N-face GaN layer.
  • a Ill-nitride film in accordance with the present invention comprises a growth of Ill-nitride resulting in a top surface which is a nitrogen face.
  • Such a film further optionally comprises a first grown layer of the growth is a group III atom layer and a last grown layer of the growth is a nitrogen layer, such that a spontaneous polarization points towards a growth surface of the Ill-nitride film, the growth is from a misoriented and nitridized surface of a substrate, and the Ill-nitride film emits light.

Landscapes

  • Physics & Mathematics (AREA)
  • Engineering & Computer Science (AREA)
  • Optics & Photonics (AREA)
  • Condensed Matter Physics & Semiconductors (AREA)
  • Electromagnetism (AREA)
  • General Physics & Mathematics (AREA)
  • Power Engineering (AREA)
  • Microelectronics & Electronic Packaging (AREA)
  • Computer Hardware Design (AREA)
  • Manufacturing & Machinery (AREA)
  • Chemical & Material Sciences (AREA)
  • Nanotechnology (AREA)
  • Life Sciences & Earth Sciences (AREA)
  • Biophysics (AREA)
  • Crystallography & Structural Chemistry (AREA)
  • Semiconductor Lasers (AREA)
  • Led Devices (AREA)

Abstract

La présente invention permet de faire croître du InGaN avec de meilleures compositions d'indium que celles disponibles jusqu'ici, ce qui amène les longueurs d'ondes des DEL et des diodes laser dans les parties jaunes et rouges du spectre chromatique. La capacité de croissance avec l'indium à des températures supérieures conduit à du AlInGaN de meilleure qualité. Cela permet également de concevoir de nouvelles structures de bande de polarisation pour créer des dispositifs plus efficaces. De plus, cela permet de fabriquer des couches de GaN de type p possédant une meilleure conductivité et, ainsi, d'augmenter les performances du dispositif.
PCT/US2007/023828 2006-11-15 2007-11-15 Diode électroluminescente et diode laser dans lesquelles sont utilisés du gan, du inn et du aln et leurs alliages face azote WO2008060531A2 (fr)

Priority Applications (1)

Application Number Priority Date Filing Date Title
JP2009537185A JP2010510655A (ja) 2006-11-15 2007-11-15 Ｎ面ＧａＮ、ＩｎＮおよびＡｌＮならびにそれらの合金を用いた発光ダイオードおよびレーザダイオード

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
US86601906P 2006-11-15 2006-11-15
US60/866,019 2006-11-15

Publications (3)

Publication Number Publication Date
WO2008060531A2 true WO2008060531A2 (fr) 2008-05-22
WO2008060531A3 WO2008060531A3 (fr) 2008-06-26
WO2008060531A9 WO2008060531A9 (fr) 2008-08-21

Family

ID=39402231

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/US2007/023828 WO2008060531A2 (fr) 2006-11-15 2007-11-15 Diode électroluminescente et diode laser dans lesquelles sont utilisés du gan, du inn et du aln et leurs alliages face azote

Country Status (2)

Country Link
JP (1) JP2010510655A (fr)
WO (1) WO2008060531A2 (fr)

Cited By (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP2284967A1 (fr) * 2009-07-14 2011-02-16 Sumitomo Electric Industries, Ltd. Diode laser à semi-conducteur en nitrure de groupe III
EP2287981A1 (fr) * 2009-07-15 2011-02-23 Sumitomo Electric Industries, Ltd. Diode de laser semi-conducteur à base de nitrure de gallium
CN102315349A (zh) * 2010-07-08 2012-01-11 Lg伊诺特有限公司 发光器件及其制造方法
WO2015065684A1 (fr) * 2013-10-29 2015-05-07 The Regents Of The University Of California Structures de dispositifs (al, in, ga, b)n sur un substrat à motifs
US9048169B2 (en) 2008-05-23 2015-06-02 Soitec Formation of substantially pit free indium gallium nitride
US9356192B2 (en) 2011-08-09 2016-05-31 Soko Kagaku Co., Ltd. Nitride semiconductor ultraviolet light-emitting element
CN105870283A (zh) * 2016-05-17 2016-08-17 东南大学 一种具有复合极性面电子阻挡层的发光二极管
US10153393B2 (en) 2013-08-22 2018-12-11 Commissariat à l'énergie atomique et aux énergies alternatives Light emitting diode of which an active area comprises layers of inn

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN108305918B (zh) * 2017-01-12 2019-07-16 中国科学院苏州纳米技术与纳米仿生研究所 氮化物半导体发光器件及其制作方法

Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20040012032A1 (en) * 2002-03-26 2004-01-22 Sanyo Electric Co., Ltd. Nitride-based semiconductor device and method of fabricating the same
US20060118799A1 (en) * 2003-10-24 2006-06-08 General Electric Company Resonant cavity light emitting devices and associated method
US20060202105A1 (en) * 2005-03-14 2006-09-14 Lumileds Lighting U.S., Llc Wavelength-converted semiconductor light emitting device
US20060202215A1 (en) * 2005-03-14 2006-09-14 Lumileds Lighting U.S., Llc Polarization-reversed III-nitride light emitting device

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20040012032A1 (en) * 2002-03-26 2004-01-22 Sanyo Electric Co., Ltd. Nitride-based semiconductor device and method of fabricating the same
US20060118799A1 (en) * 2003-10-24 2006-06-08 General Electric Company Resonant cavity light emitting devices and associated method
US20060202105A1 (en) * 2005-03-14 2006-09-14 Lumileds Lighting U.S., Llc Wavelength-converted semiconductor light emitting device
US20060202215A1 (en) * 2005-03-14 2006-09-14 Lumileds Lighting U.S., Llc Polarization-reversed III-nitride light emitting device

Cited By (13)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US9048169B2 (en) 2008-05-23 2015-06-02 Soitec Formation of substantially pit free indium gallium nitride
US8619828B2 (en) 2009-07-14 2013-12-31 Sumitomo Electronic Industries, Ltd. Group III nitride semiconductor laser diode
EP2284967A1 (fr) * 2009-07-14 2011-02-16 Sumitomo Electric Industries, Ltd. Diode laser à semi-conducteur en nitrure de groupe III
EP2287981A1 (fr) * 2009-07-15 2011-02-23 Sumitomo Electric Industries, Ltd. Diode de laser semi-conducteur à base de nitrure de gallium
US8284811B2 (en) 2009-07-15 2012-10-09 Sumitomo Electric Industries, Ltd. Gallium nitride-based semiconductor laser diode
CN102315349A (zh) * 2010-07-08 2012-01-11 Lg伊诺特有限公司 发光器件及其制造方法
EP2405496A3 (fr) * 2010-07-08 2014-11-05 LG Innotek Co., Ltd. Dispositif électroluminescent avec une face N entre deux couches semiconductrices de type-n.
US9502606B2 (en) 2011-08-09 2016-11-22 Soko Kagaku Co., Ltd. Nitride semiconductor ultraviolet light-emitting element
US9356192B2 (en) 2011-08-09 2016-05-31 Soko Kagaku Co., Ltd. Nitride semiconductor ultraviolet light-emitting element
US10153393B2 (en) 2013-08-22 2018-12-11 Commissariat à l'énergie atomique et aux énergies alternatives Light emitting diode of which an active area comprises layers of inn
WO2015065684A1 (fr) * 2013-10-29 2015-05-07 The Regents Of The University Of California Structures de dispositifs (al, in, ga, b)n sur un substrat à motifs
CN105870283B (zh) * 2016-05-17 2018-05-15 东南大学 一种具有复合极性面电子阻挡层的发光二极管
CN105870283A (zh) * 2016-05-17 2016-08-17 东南大学 一种具有复合极性面电子阻挡层的发光二极管

Also Published As

Publication number Publication date
WO2008060531A3 (fr) 2008-06-26
JP2010510655A (ja) 2010-04-02
WO2008060531A9 (fr) 2008-08-21

Similar Documents

Publication Publication Date Title
US20080111144A1 (en) LIGHT EMITTING DIODE AND LASER DIODE USING N-FACE GaN, InN, AND AlN AND THEIR ALLOYS
US10529892B2 (en) Technique for the growth and fabrication of semipolar (Ga,Al,In,B)N thin films, heterostructures, and devices
US7566580B2 (en) Method for heteroepitaxial growth of high-quality N-face GaN, InN, and AIN and their alloys by metal organic chemical vapor deposition
US8455885B2 (en) Method for heteroepitaxial growth of high-quality N-face gallium nitride, indium nitride, and aluminum nitride and their alloys by metal organic chemical vapor deposition
KR101365604B1 (ko) 유기금속 화학기상증착법을 이용한 비극성 질화인듐갈륨 박막들, 이중 구조들 및 소자들의 제조
US7687293B2 (en) Method for enhancing growth of semipolar (Al,In,Ga,B)N via metalorganic chemical vapor deposition
WO2008060531A9 (fr) Diode électroluminescente et diode laser dans lesquelles sont utilisés du gan, du inn et du aln et leurs alliages face azote
US20090039356A1 (en) Planar nonpolar m-plane group iii-nitride films grown on miscut substrates
WO2012058264A1 (fr) Limitation du relâchement des contraintes dans des hétérostructures de iii-nitrure par façonnage des couches épitaxiales et du substrat
WO2018217973A1 (fr) Couches gan semi-polaires et azote-polaires et dispositifs formés sur du saphir avec un tampon a1n à haute température
KR101028585B1 (ko) 이종 기판, 그를 이용한 질화물계 반도체 소자 및 그의 제조 방법
KR20090053549A (ko) 질화물 반도체 발광소자 및 그 제조 방법

Legal Events

Date Code Title Description
121 Ep: the epo has been informed by wipo that ep was designated in this application

Ref document number: 07861986

Country of ref document: EP

Kind code of ref document: A2

ENP Entry into the national phase in:

Ref document number: 2009537185

Country of ref document: JP

Kind code of ref document: A

NENP Non-entry into the national phase in:

Ref country code: DE

122 Ep: pct application non-entry in european phase

Ref document number: 07861986

Country of ref document: EP

Kind code of ref document: A2