Source: https://patents.google.com/patent/US8837545B2/en
Timestamp: 2019-02-16 00:21:58
Document Index: 565776449

Matched Legal Cases: ['Application No. 61', 'Application No. 61', 'Application No. 61', 'Application No. 61', 'Application No. 61', 'Application No. 61', 'Application No. 61', 'Application No. 61', 'Application No. 61', 'Application No. 61', 'Application No. 61', 'Application No. 61', 'Application No. 61']

US8837545B2 - Optical device structure using GaN substrates and growth structures for laser applications - Google Patents
Optical device structure using GaN substrates and growth structures for laser applications Download PDF
US8837545B2
US8837545B2 US13/549,335 US201213549335A US8837545B2 US 8837545 B2 US8837545 B2 US 8837545B2 US 201213549335 A US201213549335 A US 201213549335A US 8837545 B2 US8837545 B2 US 8837545B2
US13/549,335
US20130044782A1 (en
2009-04-17 Priority to US17055309P priority
2009-04-17 Priority to US17055009P priority
2009-05-11 Priority to US17721809P priority
2009-05-11 Priority to US17722709P priority
2009-05-12 Priority to US17731709P priority
2009-10-07 Priority to US24956809P priority
2010-04-16 Priority to US12/762,271 priority patent/US8294179B1/en
2010-04-16 Priority to US12/762,269 priority patent/US8254425B1/en
2010-05-12 Priority to US12/778,718 priority patent/US8242522B1/en
2010-09-17 Priority to US12/884,993 priority patent/US8351478B2/en
2012-07-13 Priority to US13/549,335 priority patent/US8837545B2/en
2012-07-13 Application filed by Soraa Laser Diode Inc filed Critical Soraa Laser Diode Inc
2012-10-25 Assigned to SORAA, INC. reassignment SORAA, INC. ASSIGNMENT OF ASSIGNORS INTEREST (SEE DOCUMENT FOR DETAILS). Assignors: RARING, JAMES W.
2013-02-21 Publication of US20130044782A1 publication Critical patent/US20130044782A1/en
2014-09-16 Publication of US8837545B2 publication Critical patent/US8837545B2/en
This application is a continuation-in-part of U.S. application Ser. No. 12/884,993 filed on Sep. 17, 2010, which claims priority from U.S. Provisional Application No. 61/249,568 filed on Oct. 7, 2009 and from U.S. Provisional Application No. 61/243,502 filed on Sep. 17, 2009; and this application is a continuation-in-part of U.S. application Ser. No. 12/778,718 filed on May 12, 2010, which claims priority from U.S. Provisional Application No. 61/177,317 filed on May 12, 2009; and this application is a continuation-in-part of U.S. application Ser. No. 12/762,269 filed on Apr. 16, 2010, which claims priority from U.S. Provisional Application No. 61/243,502 filed on Sep. 17, 2009, from U.S. Provisional Application No. 61/177,218 filed on May 11, 2009, from U.S. Provisional Application No. 61/170,550 filed on Apr. 17, 2009, and from U.S. Provisional Application No. 61/170,553 filed on Apr. 17, 2009; and this application is a continuation-in-part of U.S. application Ser. No. 12/762,271 filed on Apr. 16, 2010, which claims priority from U.S. Provisional Application No. 61/243,502 filed on Sep. 17, 2009, from U.S. Provisional Application No. 61/177,227 filed on May 11, 2009, from U.S. Provisional Application No. 61/170,550 filed on Apr. 17, 2009, and from U.S. Provisional Application No. 61/170,553 filed on Apr. 17, 2009; and this application is a continuation-in-part of U.S. application Ser. No. 12/759,273 filed on Apr. 13, 2010, which claims priority from U.S. Provisional Application No. 61/243,502 filed on Sep. 17, 2009, and from U.S. Provisional Application No. 61/168,926 filed on Apr. 13, 2009; each of which is commonly-assigned and each of which are hereby incorporated by reference in its entirety.
In the late 1800's, Thomas Edison invented the light bulb. The conventional light bulb, commonly called the “Edison bulb,” has been used for over one hundred years for a variety of applications including lighting and displays. The conventional light bulb uses a tungsten filament enclosed in a glass bulb sealed in a base, which is screwed into a socket. The socket is coupled to an AC or DC power source. The conventional light bulb can be found commonly in houses, buildings, and outdoor lightings, and other areas requiring light or displays.
Unfortunately, drawbacks exist with the conventional Edison light bulb. First, the conventional light bulb dissipates much thermal energy. More than 90% of the energy used for the conventional light bulb dissipates as thermal energy. Second, reliability is less than desired—the conventional light bulb routinely fails due to thermal expansion and contraction of the filament element. In addition, conventional light bulbs emit light over a broad spectrum, much of which does not result in illumination at wavelengths of spectral sensitivity to the human eye. Finally, conventional light bulbs emit light in all directions. They therefore are not ideal for applications requiring strong directionality or focus, such as projection displays, optical data storage, or specialized directed lighting.
In 1960, the laser was first demonstrated by Theodore H. Maiman at Hughes Research Laboratories in Malibu. This laser utilized a solid-state flashlamp-pumped synthetic ruby crystal to produce red laser light at 694 nm. By 1964, blue and green laser output was demonstrated by William Bridges at Hughes Aircraft utilizing a gas Argon ion laser. The Ar-ion laser utilized a noble gas as the active medium and produced laser light output in the UV, blue, and green wavelengths including 351 nm, 454.6 nm, 457.9 nm, 465.8 nm, 476.5 nm, 488.0 nm, 496.5 nm, 501.7 nm, 514.5 nm, and 528.7 nm. The Ar-ion laser had the benefit of producing highly directional and focusable light with a narrow spectral output, but the wall plug efficiency was less than 0.1%. The size, weight, and cost of the laser was undesirable as well.
As laser technology evolved, more efficient lamp pumped solid state laser designs were developed for the red and infrared wavelengths, but these technologies remained a challenge for blue and green lasers. As a result, lamp pumped solid state lasers were developed in the infrared, and the output wavelength was converted to the visible using specialty crystals with nonlinear optical properties. A green lamp pumped solid state laser had 3 stages: electricity powers lamp, lamp excites gain crystal which lases at 1064 nm, 1064 nm goes into frequency conversion crystal which converts to visible 532 nm. The resulting green and blue lasers were called “lamped pumped solid state lasers with second harmonic generation” (LPSS with SHG). These had wall plug efficiency of ˜1%, and were more efficient than Ar-ion gas lasers, but were still too inefficient, large, expensive, and fragile for broad deployment outside of specialty scientific and medical applications. Additionally, the gain crystal used in the solid state lasers typically had energy storage properties which made the lasers difficult to modulate at high speeds, limiting broader deployment.
To improve the efficiency of these visible lasers, high power diode (or semiconductor) lasers were utilized. These “diode pumped solid state lasers with SHG” (DPSS with SHG) had 3 stages: electricity powers 808 nm diode laser, 808 nm excites gain crystal which lases at 1064 nm, 1064 nm goes into frequency conversion crystal which converts to visible 532 nm. The DPSS laser technology extended the life and improved the wall plug efficiency of the LPSS lasers to 5-10%. This sparked further commercialization into specialty industrial, medical, and scientific applications. The change to diode pumping, however, increased the system cost and required precise temperature controls, leaving the laser with substantial size and power consumption. The result did not address the energy storage properties which made the lasers difficult to modulate at high speeds.
As high power laser diodes evolved and new specialty SHG crystals were developed, it became possible to directly convert the output of the infrared diode laser to produce blue and green laser light output. These “directly doubled diode lasers” or SHG diode lasers had 2 stages: electricity powers 1064 nm semiconductor laser, 1064 nm goes into frequency conversion crystal which converts to visible 532 nm green light. These lasers designs are intended to provide improved efficiency, cost and size compared to DPSS-SHG lasers, but the specialty diodes and crystals required make this challenging today. Additionally, while the diode-SHG lasers have the benefit of being directly modulated, they suffer from sensitivity to temperature which limits their application. Further, the spectral linewidth of SHG-based lasers is typically very narrow at about 0.1 nm, which can lead to a severe image distortion called speckle in display applications.
This invention provides an optical device, which includes a gallium nitride substrate having a semipolar or nonpolar crystalline surface region. The device also has an n-type cladding layer overlying the substrate surface. In a preferred embodiment, the n-type GaN cladding layer has a thickness from 100 nm to 5000 nm with a silicon doping level of 1E17 to 5E18 cm-3. The device has an n-side SCH layer overlying the n-type cladding layer. Preferably, the n-side SCH layer is comprised of InGaN with molar fraction of indium of between 1% and 7% and has a thickness from 40 to 150 nm. The optical device also has a multiple quantum well active region overlying the n-side SCH layer. Preferably, the multiple quantum well active region is comprised of two to five 2.5-4.5 nm InGaN quantum wells separated by 3.7-5.5 nm or 7.5 to 20 nm gallium and nitrogen containing barriers such as GaN. Preferably the optical device has a p-side guide layer overlying the multiple quantum well active region. In a preferred embodiment, the p-side guide layer comprises GaN or InGaN and has a thickness from 20 nm to 100 nm. The optical device has an electron blocking layer overlying the p-side guide layer. Preferably, the electron blocking layer comprises a magnesium doped AlGaN layer with molar fraction of aluminum of between 6% and 22% at a thickness from 10 nm to 25 nm. Preferably the optical device also has a p-type cladding layer overlying the electronic blocking layer. The p-type cladding layer has a thickness from 300 nm to 1000 nm with a magnesium doping level of 2E17 cm-3 to 1E19 cm-3 according to one or more embodiments. The device also has a p++-gallium and nitrogen contact layer overlying the p-type cladding layer. The P++-gallium and nitrogen containing layer typically has a thickness from 10 nm to 120 nm with a Mg doping level of 1E19 cm-3 to 1E21 cm-3.
FIG. 1A is a simplified perspective view of a laser device 100 fabricated on a semipolar substrate according to an embodiment of the present invention. This diagram is merely an example, which should not unduly limit the scope of the claims herein. One of ordinary skill in the art would recognize other variations, modifications, and alternatives. As shown, the optical device includes a gallium nitride substrate member 101 having a semipolar or non-polar crystalline surface region. In a specific embodiment, the gallium nitride substrate member is a bulk GaN substrate characterized by having a semipolar or non-polar crystalline surface region, but can be others. In a specific embodiment, the bulk nitride GaN substrate comprises nitrogen and has a surface dislocation density below 107 cm−2 or 105 cm−2. The nitride crystal or wafer may comprise AlxInyGa1-x-yN, where 0≦x, y, x+y≦1. In one specific embodiment, the nitride crystal comprises GaN. In one or more embodiments, the GaN substrate has threading dislocations, at a concentration between about 105 cm−2 and about 108 cm−2, in a direction that is substantially orthogonal or oblique with respect to the surface. As a consequence of the orthogonal or oblique orientation of the dislocations, the surface dislocation density is below about 107 cm−2 or below about 105 cm−2. In a specific embodiment, the device can be fabricated on a slightly off-cut semipolar substrate as described in U.S. application Ser. No. 12/749,466, which claims priority to U.S. Provisional No. 61/164,409 filed on Mar. 28, 2009, commonly assigned, and hereby incorporated by reference herein.
In a specific embodiment on nonpolar GaN, the device has a laser stripe region formed overlying a portion of the semi or non-polar crystalline orientation surface region, as illustrated by FIG. 1B. The laser stripe region is characterized by a cavity orientation which is substantially parallel to the c-direction. The laser strip region has a first end and a second end. Typically, the non-polar crystalline orientation is configured on an m-plane, which leads to polarization ratios parallel to the a-direction. In some embodiments, the m-plane is the (10-10) family. Of course, the cavity orientation can also be substantially parallel to the a-direction as well. In the specific nonpolar GaN embodiment having the cavity orientation substantially parallel to the c-direction is further described in “Laser Device and Method Using Slightly Miscut Non-Polar GaN Substrates,” in the names of Raring, James W. and Pfister, Nick listed as U.S. application Ser. No. 12/759,273, which claims priority to U.S. Provisional Ser. No. 61/168,926 filed on Apr. 13, 2009, commonly assigned, and hereby incorporated by reference for all purposes.
In a specific embodiment, the device also has an overlying n-type gallium nitride layer 205, an active region 207, and an overlying p-type gallium nitride layer structured as a laser stripe region 209. In a specific embodiment, each of these regions is formed using an epitaxial deposition technique of metal organic chemical vapor deposition (MOCVD), molecular beam epitaxy (MBE), or other epitaxial growth techniques suitable for GaN growth. In a specific embodiment, the epitaxial layer is a high quality epitaxial layer overlying the n-type gallium nitride layer. In some embodiments the high quality layer is doped, for example, with Si or O to form n-type material, with a dopant concentration between about 1016 cm−3 and 1020 cm−3.
As an example, the bulk GaN substrate is placed on a susceptor in an MOCVD reactor. After closing, evacuating, and back-filling the reactor (or using a load lock configuration) to atmospheric pressure, the susceptor is heated to a temperature between about 800 and about 1100 degrees Celsius in the presence of a nitrogen-containing gas. In one specific embodiment, the susceptor is heated to approximately 1000 degrees Celsius under flowing ammonia. A flow of a gallium-containing metalorganic precursor, such as trimethylgallium (TMG) or triethylgallium (TEG) is initiated, in a carrier gas, at a total rate between approximately 1 and 50 standard cubic centimeters per minute (sccm). The carrier gas may comprise hydrogen, helium, nitrogen, or argon. The ratio of the flow rate of the group V precursor (ammonia) to that of the group III precursor (trimethylgallium, triethylgallium, trimethylindium, trimethylaluminum) during growth is between about 2000 and about 12000. A flow of disilane in a carrier gas, with a total flow rate of between about 0.1 and 10 sccm, is initiated.
In a specific embodiment, the laser device has active region 207. The active region can include one to twenty quantum well regions according to one or more embodiments. As an example following deposition of the n-type AluInvGa1-u-vN layer for a predetermined period of time, so as to achieve a predetermined thickness, an active layer is deposited. The active layer may comprise a single quantum well or a multiple quantum well, with 1-10 quantum wells. The quantum wells may comprise InGaN wells and GaN barrier layers. In other embodiments, the well layers and barrier layers comprise AlwInxGa1-w-xN and AlyInzGa1-y-zN, respectively, where 0≦w, x, y, z, w+x, y+z≦1, where w<u, y and/or x>v, z so that the bandgap of the well layer(s) is less than that of the barrier layer(s) and the n-type layer. The well layers and barrier layers may each have a thickness between about 1 nm and about 40 nm. In another embodiment, the active layer comprises a double heterostructure, with an InGaN or AlwInxGa1-w-xN layer about 10 nm to 100 nm thick surrounded by GaN or AlyInzGa1-y-zN layers, where w<u, y and/or x>v, z. The composition and structure of the active layer are chosen to provide light emission at a preselected wavelength. The active layer may be left undoped (or unintentionally doped) or may be doped n-type or p-type.
As noted, the p-type gallium nitride structure, which can be a p-type doped AlqInrGa1-q-rN, where 0≦q, r, q+r≦1, layer is deposited above the active layer. The p-type layer may be doped with Mg, to a level between about 1016 cm−3 and 1022 cm−3, and may have a thickness between about 5 nm and about 1000 nm. The outermost 1-50 nm of the p-type layer may be doped more heavily than the rest of the layer, so as to enable an improved electrical contact. In a specific embodiment, the laser stripe is provided by a dry etching process, but wet etching may also be used. The device also has an overlying dielectric region, which exposes contact region 213. In a specific embodiment, the dielectric region is an oxide such as silicon dioxide.
In a preferred embodiment, the growth structure is configured using between 2 and 4 or 5 and 7 quantum wells positioned between n-type and p-type gallium and nitrogen containing cladding layers such as GaN, AlGaN, or InAlGaN. In a specific embodiment, the n-type cladding layer ranges in thickness from 500 nm to 5000 nm and has an n-type dopant such as Si with a doping level of between 1E18 cm−3 and 3E18 cm−3. In a specific embodiment, the p-type cladding layer ranges in thickness from 300 nm to 1000 nm and has a p-type dopant such as Mg with a doping level of between 1E17 cm−3 and 5E19 cm−3. In a specific embodiment, the Mg doping level is graded such that the concentration would be lower in the region closer to the quantum wells.
Preferably, a p-contact layer positioned on top of and is formed overlying the p-type cladding layer. The p-contact layer would be comprised of a gallium and nitrogen containing layer such as GaN doped with a p-dopant such as Mg at a level ranging from 1E19 cm−3 to 1E22 cm−3.
an n-type cladding layer with a thickness from 1000 nm to 5000 nm with Si doping level of 1E17 cm−3 to 3E18 cm−3;
a p-type cladding layer with a thickness from 300 nm to 1000 nm with Mg doping level of 5E17 cm−3 to 1E19 cm−3; and
a p++-GaN contact layer with a thickness from 20 nm to 55 nm with Mg doping level of 1E20 cm−3 to 1E21 cm3.
In a specific embodiment, the above laser device is fabricated on a nonpolar oriented surface region. Preferably, the 474 nm configured laser device uses a nonpolar (10-10) substrate with a miscut or off cut of −0.3 to 0.3 degrees towards (0001) and −0.3 to 0.3 degrees towards (11-20). In a specific embodiment, the n-GaN/p-GaN is grown using an N2 subflow and N2 carrier gas.
an n-GaN cladding layer with a thickness from 100 nm to 5000 nm with Si doping level of 5E17 cm−3 to 3E18 cm−3;
a p-GaN cladding layer with a thickness from 400 nm to 1000 nm with Mg doping level of 5E17 cm−3 to 1E19 cm−3; and
p++-GaN contact layer with a thickness from 20 nm to 40 nm with Mg doping level of 2E19 cm−3 to 1E21 cm−3.
In a specific embodiment, the laser device is fabricated on a non-polar (10-10) oriented surface region (m-plane). In a preferred embodiment, the non-polar substrate has a miscut or off cut of −0.8 to −1.2 degrees towards (0001) and −0.3 to 0.3 degrees towards (11-20). In a specific embodiment, the non-polar oriented surface region has an overlying n-GaN/p-GaN grown with H2/N2 subflow and H2 carrier gas.
an n-GaN cladding layer with a thickness from 100 nm to 3000 nm with Si doping level of 5E17 cm−3 to 3E18 cm−3;
a p-GaN cladding layer with a thickness from 400 nm to 1000 nm with Mg doping level of 2E17 cm−3 to 4E19 cm−3; and
a p++-GaN contact layer with a thickness from 20 nm to 40 nm with Mg doping level of 5E19 cm−3 to 1E21 cm−3.
In a specific embodiment, the laser device is fabricated on a non-polar oriented surface region (m-plane). In a preferred embodiment, the non-polar substrate has a miscut or off cut of −0.8 to −1.2 degrees towards (0001) and −0.3 to 0.3 degrees towards (11-20). In a specific embodiment, the non-polar oriented surface region has an overlying n-GaN/p-GaN grown with H2/N2 subflow and H2 carrier gas.
an n-GaN cladding layer with a thickness from 100 nm to 3000 nm with Si doping level of 5E17 to 3E18 cm−3;
a p++-GaN contact layer with a thickness from 20 nm to 40 nm with Mg doping level of 1E20 cm−3 to 1E21 cm−3.
In a specific embodiment, the laser device is fabricated on a non-polar (10-10) oriented surface region (m-plane). In a preferred embodiment, the non-polar substrate has a miscut or off cut of −0.8 to −1.2 degrees towards (0001) and −0.3 to 0.3 degrees towards (11-20). In a specific embodiment, the non-polar oriented surface region has an overlying n-GaN/p-GaN grown with H2/N2 subflow and H2 carrier gas. In a preferred embodiment, the laser device configured for a 500 nm laser uses well regions and barriers fabricated using slow growth rates of between 0.3 and 0.6 angstroms per second, but can be others. In a specific embodiment, the slow growth rate is believed to maintain the quality of the InGaN at longer wavelengths.
a gallium nitride substrate member having a semipolar crystalline surface region, the substrate member having a thickness of less than 500 microns, the gallium and nitride substrate member characterized by a dislocation density of less than 107 cm−2;
a gallium and nitrogen containing n-type cladding layer overlying the surface region, the n-type cladding layer having a thickness from 300 nm to 6000 nm with an n-type doping level of 1E17 cm−3 to 3E18 cm−3;
a p-type gallium and nitrogen containing cladding layer overlying the multiple quantum well active region, the p-type cladding layer having a thickness from 300 nm to 1000 nm with a p-type doping level of 1E17 cm−3 to 5E19 cm−3;
a p++ gallium and nitrogen containing contact layer overlying the p-type cladding layer, the p++ gallium and nitrogen containing contact layer having a thickness from 10 nm to 120 nm with a p-type doping level of 1E19 cm−3 to 1E22 cm−3;
a surface reconstruction region configured overlying the semipolar surface region and the n-type cladding layer and at an interface within a vicinity of the semipolar surface region, the surface reconstruction region having an oxygen bearing concentration of greater than 1E17 cm−3;
an n-type cladding layer comprising a first quaternary alloy, the first quaternary alloy comprising an aluminum bearing species, an indium bearing species, a gallium bearing species, and a nitrogen bearing species overlying the surface region, the n-type cladding layer having a thickness from 100 nm to 5000 nm with an n-type doping level of 1E17 cm−3 to 6E18 cm−3;
a p-type cladding layer comprising a second quaternary alloy overlying the second gallium and nitrogen containing material, the p-type cladding layer having a thickness from 300 nm to 1000 nm with a magnesium doping level of 1E17 cm−3 to 4E19 cm−3;
a plurality of hydrogen species, the plurality of hydrogen species spatially disposed within the p-type cladding layer;
a p++ gallium and nitrogen containing contact layer overlying the p-type cladding layer, the p++ gallium and nitrogen containing contact layer having a thickness from 10 nm to 140 nm with a magnesium doping level of 1E19 cm−3 to 1E22 cm−3; and
In this example, the present method includes providing a gallium nitride substrate member having a semipolar crystalline surface region. The substrate member has a thickness of less than 500 microns, which has been thinned to less than 100 microns by way of a thinning process, e.g., grinding polishing. The gallium and nitride substrate member is characterized by a dislocation density of less than 107 cm−2. The semipolar surface region is characterized by an off-set of +/−3 degrees from a (20-21) semipolar plane toward a c-plane. As an example, the gallium nitride substrate can be made using bulk growth techniques such as ammonothermal based growth or HVPE growth with extremely high quality seeds to reduce the dislocation density to below 1E5 cm−2, below 1E3 cm−2, or eventually even below 1E1 cm−2.
In this example, the method also includes forming the surface reconstruction region overlying the semipolar surface region. The reconstruction region is formed by heating the substrate in the growth reactor to above 1000° C. with an ammonia (e.g., NH3) and hydrogen (e.g., H2) over pressure, e.g., atmospheric. The heating process flattens and removes micro-scratches and other imperfections on the substrate surface that lead to detrimental device performance. The micro-scratches and other imperfections are often caused by substrate preparation, including grinding, lapping, and polishing, among others.
The method includes forming the n-side separate confining heterostructure (SCH) waveguiding layer comprises processing at a deposition rate of less than 1.5 angstroms per second and an oxygen concentration of less than 8E17 cm−3. In this example, the n-side SCH is an InGaN material having a thickness and an oxygen concentration. The oxygen concentration is preferably below a predetermined level within a vicinity of the multiple quantum well regions to prevent any detrimental influences therein. Further details of the multiple quantum well region are provided below.
In this example, the method includes forming the multiple quantum well active region by processing at a deposition rate of less than 1 angstroms per second and an oxygen concentration of less than 8E17 cm−3. The method also includes forming the p-side guide layer overlying the multiple quantum well active region by depositing an InGaN SCH layer with an InN molar fraction of between 1% and 5% and a thickness ranging from 10 nm to 100 nm. The method forms the second gallium and nitrogen-containing material overlying the p-side guide layer by a process comprising a p-type GaN guide layer with a thickness ranging from 50 nm to 300 nm. As an example, the quantum well region can include two to four well regions, among others. Each of the quantum well layers is substantially similar to each other for improved device performance, or may be different.
In this example, the method includes forming an electron blocking layer overlying the p-side guide layer, the electron blocking layer comprising AlGaN with a molar fraction of AlN of between 6% and 22% and having a thickness from 5 nm to 25 nm and doped with a p-type dopant such as magnesium. The method includes forming the p-type cladding layer comprising a hydrogen species that has a concentration that tracks relatively with the p-type dopant concentration. The method includes forming a p++-gallium and nitrogen containing contact layer comprising a GaN material formed with a growth rate of less than 2.5 angstroms per second and characterized by a magnesium concentration of greater than 5E19 cm−3. Preferably, the electron-blocking layer redirects electrons from the active region back into the active region for radiative recombination.
a gallium and nitrogen containing substrate member having a semipolar crystalline surface region, the gallium and nitrogen containing substrate member having a thickness of less than 500 microns, the gallium and nitrogen containing substrate member characterized by a dislocation density of less than 107 cm−2;
the semipolar crystalline surface region having a root mean square surface roughness of 10 nm or less over a 5 micron by 5 micron analysis area;
an offcut characterizing the semipolar crystalline surface region;
a gallium and nitrogen containing n-type cladding layer overlying the semipolar crystalline surface region, the gallium and nitrogen containing n-type cladding layer having a thickness from 300 nm to 6000 nm with an n-type doping level of 1E17 cm−3 to 3E18 cm−3;
an n-side separate confining heterostructure (SCH) waveguide layer overlying the gallium and nitrogen containing n-type cladding layer, the n-side SCH waveguide layer comprised of at least gallium, indium, and nitrogen with molar fraction of InN of between 1% and 8% and having a thickness from 20 nm to 150 nm;
a multiple quantum well active region overlying the n-side SCH waveguide layer, the multiple quantum well active region comprising two to five InGaN quantum wells having a thickness from 2.0 nm to 4.5 nm and being separated by gallium and nitrogen containing barrier layers having a thickness from 3.5 nm to 20 nm;
a p-side guide layer overlying the multiple quantum well active region, the p-side guide layer comprised of GaN or InGaN and having a thickness from 10 nm to 120 nm;
a p-type gallium and nitrogen containing cladding layer overlying the multiple quantum well active region, the p-type gallium and nitrogen containing cladding layer having a thickness from 300 nm to 1000 nm with a p-type doping level of 1E17 cm−3 to 5E19 cm−3;
a p++ gallium and nitrogen containing contact layer overlying the p-type gallium and nitrogen containing cladding layer, the p++ gallium and nitrogen containing contact layer having a thickness from 10 nm to 120 nm with a p-type doping level of 1E19 cm−3 to 1E22 cm−3;
2. The device of claim 1 further comprising an electron blocking layer overlying the p-side guide layer, the electron blocking layer comprising AlGaN with a molar fraction of AlN of between 6% and 22% and having a thickness from 5 nm to 25 nm and doped with magnesium.
3. The device of claim 1 wherein the gallium and nitrogen containing n-type cladding layer comprises n-type AlGaN.
4. The device of claim 1 wherein the gallium and nitrogen containing n-type cladding layer comprises n-type InAlGaN.
5. The device of claim 1 wherein the p-type gallium and nitrogen containing cladding layer comprises p-type AlGaN.
6. The device of claim 1 wherein the p-type gallium and nitrogen containing cladding layer comprises p-type InAlGaN.
7. The device of claim 1 wherein the gallium and nitrogen containing barrier layers comprise GaN and/or AlGaN.
8. The device of claim 1 wherein the first facet includes a semipolar characteristic.
9. The device of claim 1 wherein the second facet includes a semipolar characteristic.
10. The device of claim 1 wherein the semipolar crystalline surface region is characterized by an off-set of +/−3 degrees from a (20-21) semipolar plane toward a c-plane.
a gallium and nitrogen containing substrate member having a semipolar crystalline surface region, the gallium and nitrogen containing substrate member having a thickness of less than 450 microns, the gallium and nitrogen containing substrate member characterized by a dislocation density of less than 107 cm−2;
an n-type cladding layer comprising at least an aluminum bearing species, a gallium bearing species, and a nitrogen bearing species overlying the semipolar crystalline surface region, the n-type cladding layer having a thickness from 100 nm to 5000 nm with an n-type doping level of 1E17 cm−3 to 6E18 cm−3;
a first gallium and nitrogen containing epitaxial material comprising a first portion including a first indium concentration, a second portion including a second indium concentration, and a third portion including a third indium concentration overlying the n-type cladding layer;
an n-side separate confining heterostructure (SCH) waveguide layer overlying the n-type cladding layer, the n-side SCH waveguide layer comprising InGaN with a molar fraction of InN of between 1% and 8% and having a thickness from 30 nm to 150 nm;
a multiple quantum well active region overlying the n-side SCH waveguide layer, the multiple quantum well active region comprising two to five InGaN quantum wells having a thickness from 2.0 nm to 4.5 nm and being separated by gallium and nitrogen containing barrier layers having a thickness from 5.5 nm to 18 nm;
a p-side guide layer overlying the multiple quantum well active region, the p-side guide layer comprised of GaN or InGaN and having a thickness from 20 nm to 100 nm;
a p-type cladding layer comprising at least an aluminum bearing species, a gallium bearing species, and a nitrogen bearing species overlying the p-side guide layer, the p-type cladding layer having a thickness from 250 nm to 1000 nm with a p-type doping level of 1E17 cm−3 to 5E19 cm−3;
a p++ gallium and nitrogen containing contact layer overlying the p-type cladding layer, the p++ gallium and nitrogen containing contact layer having a thickness from 10 nm to 100 nm with a p-type doping level of 1E19 cm−3 to 1E22 cm−3;
a waveguide member, the waveguide member being aligned substantially in a projection of the c-direction, the waveguide member comprising a first end and a second end;
a second etched surface formed on the second edge region;
whereupon the waveguide member is provided between the first facet and the second facet, the waveguide member having a length of greater than 300 microns and configured to emit substantially polarized electromagnetic radiation such that a polarization is substantially orthogonal to a waveguide cavity direction and the substantially polarized electromagnetic radiation having a wavelength of 500 nm and greater and a spontaneous emission spectral full width at half maximum of less than 50 nm in a light emitting diode mode of operation.
12. The device of claim 11 wherein the n-type cladding layer comprises n-type AlGaN.
13. The device of claim 11 wherein the n-type cladding layer comprises n-type InAlGaN.
14. The device of claim 11 wherein the p-type cladding layer comprises p-type AlGaN.
15. The device of claim 11 wherein the p-type cladding layer comprises p-type InAlGaN.
16. The device of claim 11 wherein the gallium and nitrogen containing barrier layers comprise GaN and/or AlGaN.
17. The device of claim 11 wherein the semipolar crystalline surface region is characterized by an off-set of +/−3 degrees from a (20-21) semipolar plane toward a c-plane.
an n-type cladding layer comprising a first quaternary alloy, the first quaternary alloy comprising an aluminum bearing species, an indium bearing species, a gallium bearing species, and a nitrogen bearing species overlying the semipolar crystalline surface region, the n-type cladding layer having a thickness from 100 nm to 5000 nm with an n-type doping level of 1E17 cm−3 to 6E18 cm−3;
a surface reconstruction region overlying the semipolar crystalline surface region and the n-type cladding layer and at an interface within a vicinity of the semipolar crystalline surface region, the surface reconstruction region having an oxygen bearing concentration of greater than 1E17 cm−3;
a first gallium and nitrogen containing material comprising a first portion including a first indium concentration, a second portion including a second indium concentration, and a third portion including a third indium concentration overlying the n-type cladding layer;
an n-side separate confining heterostructure (SCH) waveguide layer overlying the n-type cladding layer, the n-side SCH waveguide layer comprised of InGaN with molar fraction of InN of between 1% and 8% and having a thickness from 30 nm to 150 nm;
a multiple quantum well active region overlying the n-side SCH waveguide layer, the multiple quantum well active region comprising two to five InGaN quantum wells having a thickness from 2.0 nm to 4.5 nm and being separated by gallium and nitrogen containing barrier layers having a thickness from 5 nm to 20 nm;
a p-side guide layer overlying the multiple quantum well active region, the p-side guide layer comprising GaN or InGaN and having a thickness from 20 nm to 100 nm;
a p-type cladding layer comprising a second quaternary alloy overlying the second gallium and nitrogen containing material, the p-type cladding layer having a thickness from 250 nm to 1000 nm and comprising a p-type doping species including magnesium at a concentration of 1E17 cm−3 to 4E19 cm−3;
a p++ gallium and nitrogen containing contact layer overlying the p-type cladding layer, the p++ gallium and nitrogen containing contact layer having a thickness from 10 nm to 140 nm and comprising a p-type doping species including magnesium at a concentration of 1E19 cm−3 to 1E22 cm−3;
whereupon the waveguide member is provided between the first facet and the second facet, the waveguide member having a length of greater than 300 microns and configured to emit substantially polarized electromagnetic radiation such that a polarization is substantially orthogonal to a waveguide cavity direction and the substantially polarized electromagnetic radiation having a wavelength of 500 nm and greater and a spontaneous emission spectral full width at half maximum of less than 50 nm in a light emitting diode mode of operation or a spectral line-width of a laser output of greater than 0.4 nm.
US13/549,335 2009-04-13 2012-07-13 Optical device structure using GaN substrates and growth structures for laser applications Active US8837545B2 (en)
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US12/762,269 US8254425B1 (en) 2009-04-17 2010-04-16 Optical device structure using GaN substrates and growth structures for laser applications
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US13/549,335 US8837545B2 (en) 2009-04-13 2012-07-13 Optical device structure using GaN substrates and growth structures for laser applications
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US15/380,156 US9735547B1 (en) 2009-04-13 2016-12-15 Optical device structure using GaN substrates and growth structures for laser applications
US15/671,384 US9941665B1 (en) 2009-04-13 2017-08-08 Optical device structure using GaN substrates and growth structures for laser applications
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US12/762,271 Continuation-In-Part US8294179B1 (en) 2009-04-17 2010-04-16 Optical device structure using GaN substrates and growth structures for laser applications
US12/762,269 Continuation-In-Part US8254425B1 (en) 2009-04-17 2010-04-16 Optical device structure using GaN substrates and growth structures for laser applications
US12/778,718 Continuation-In-Part US8242522B1 (en) 2009-05-12 2010-05-12 Optical device structure using non-polar GaN substrates and growth structures for laser applications in 481 nm
US12/884,993 Continuation-In-Part US8351478B2 (en) 2009-09-17 2010-09-17 Growth structures and method for forming laser diodes on {30-31} or off cut gallium and nitrogen containing substrates
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US14/601,651 Active US9099844B2 (en) 2009-04-13 2015-01-21 Optical device structure using GaN substrates and growth structures for laser applications
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