Nitride semiconductor laser device and a method for improving its performance

a laser device and nitride technology, applied in the direction of semiconductor lasers, crystal growth process, polycrystalline material growth, etc., can solve the problems of affecting the lifetime of over 100 mw laser diodes, and affecting the performance of nitride semiconductor laser devices. achieve the effect of improving the performance of a nitride semiconductor laser devi

Inactive Publication Date: 2008-02-28
AMMONO SP Z O O (PL)
View PDF6 Cites 26 Cited by
  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Benefits of technology

[0012] The object of this invention is to develop a nitride semiconductor laser with a resonator radiation-emitting end face covered with a nitride window layer without impairing laser performance parameters.
[0014] A further object of the present invention is to provide a method for improving performance of nitride semiconductor laser device involving manufacturing a nitride laser with a satisfactory nitride window layer.
[0018] at least the radiation-emitting end face of said resonator is covered by said window layer comprising monocrystalline nitride of general formula AlxGa1-x-yInyN, where 0≦x+y≦1, 0≦x≦1 and 0≦y<1, especially nitride of general formula AlxGa1-xN (0≦x≦1) having a wider energy gap than that of the active layer and being formed at a low temperature so as not to damage said active layer. In this invention, a term “window layer” denotes a layer having a wider energy gap than that of the active layer or the quantum well layer, which is formed directly on the radiation-emitting end face of resonator for avoiding the problems caused by the narrower energy gap of the end face of the resonator.
[0030] in a second process the resonator radiation-emitting end face is covered by a window layer of monocrystalline nitride of general formula AlxGa1-x-yInyN, where 0≦x+y≦1, 0≦x≦1 and 0≦y<1, especially nitride of general formula AlxGa1-xN (0≦x≦1), having a wider energy gap than that of the active layer, at low temperature so as not to damage said active layer.
[0032] In the method for improving the performance of a nitride semiconductor laser device according to the present invention, during the second process the resonator end face window layer is formed after at least upper surface of resonator p-type contact layer is covered by a mask having higher or same chemical resistance than that of end face window layer material in supercritical ammonia-containing solution.
[0034] In the method for improving the performance of a nitride semiconductor laser device according to the present invention the resonator end face window layer is formed by depositing monocrystalline nitride layer of the above described composition in the supercritical ammonia-containing solution at a temperature of 800° C. or less, preferably 600° C. or less.

Problems solved by technology

In nitride semiconductor lasers, resonator mirrors are obtained as a result of Reactive Ion Etching (RIE) or cleavage, and—due to energy gap narrowing—they absorb emitted radiation, which results in heat generation leading to impairment of the lifetime of over 100 mW laser diodes.
However, such high temperatures cause damage to the active layer formed of an indium-containing nitride semiconductor as used in nitride semiconductor lasers so far.
Moreover, as a result of tinge caused by amorphousness, light absorption and end face heating occur, which consequently leads to accelerated degradation thereof.

Method used

the structure of the environmentally friendly knitted fabric provided by the present invention; figure 2 Flow chart of the yarn wrapping machine for environmentally friendly knitted fabrics and storage devices; image 3 Is the parameter map of the yarn covering machine
View more

Image

Smart Image Click on the blue labels to locate them in the text.
Viewing Examples
Smart Image
  • Nitride semiconductor laser device and a method for improving its performance
  • Nitride semiconductor laser device and a method for improving its performance
  • Nitride semiconductor laser device and a method for improving its performance

Examples

Experimental program
Comparison scheme
Effect test

example 1

[0111] First, the sapphire wafer 1 of 2 inch diameter and a surface essentially perpendicular to c-axis is placed in the MOCVD reactor. Temperature is set at 510° C. Hydrogen is used as carrier gas and gaseous substrates of the reaction are: ammonia and TMG (thrimethylgallium). The GaN buffer layer 11 of 200 angstrom thick is formed on the sapphire wafer, in the conditions of low-temperature growth.

[0112] On the buffer layer, the following layers are deposited one after the other: [0113] (1) 4 μm thick n-type GaN contact layer, doped with Si at the level of 3×1018 / cm3. [0114] (2) 1.5 μm thick undoped In0.06Ga0.94N crack-preventing layer. [0115] (3) n-type clad layer, in the form of the superlattice of the total thickness being 1.2 μm, formed by alternate deposition of 25 angstroms thick undoped In0.1Ga0.9N layers and n-type GaN layers doped with Si at the level of 1×1019 / cm3. [0116] (4) 0.2 μm thick undoped n-type GaN optical guide layer of. [0117] (5) the active layer of the total...

example 2

[0133] In this Example 2, only the resonator radiation-emitting end face is covered with a GaN monocrystalline layer, whereas other stages of laser production are carried out as in Example 1. The laser element made in this way is also equipped with a heat sink. Similar as in Example 1, the average lifetime of the laser—with the threshold current density of 2.0 kA / cm2, the power output of 100 mW and the 405 nm light wavelength—is extended.

example 3

[0134] In this Example 3, after the buffer layer is formed on a sapphire wafer, a 100 μm thick GaN layer is deposited by the HVPE method. Next, as in Example 1, the n-type nitride semiconductor layer, the active layer and the p-type nitride semiconductor layer are formed. Next, sapphire is removed and consequently a homogenous GaN substrate is obtained. In the successive stages, as in Example 1, resonator end faces are uncovered and subsequently covered with a 0.5 μm thick GaN monocrystalline layer crystallized in the environment of a supercritical ammonia-containing solution. In the case of the nitride semiconductor laser thus obtained, its parameters may be expected to get improved as in Example 1.

the structure of the environmentally friendly knitted fabric provided by the present invention; figure 2 Flow chart of the yarn wrapping machine for environmentally friendly knitted fabrics and storage devices; image 3 Is the parameter map of the yarn covering machine
Login to view more

PUM

PropertyMeasurementUnit
temperatureaaaaaaaaaa
temperatureaaaaaaaaaa
temperatureaaaaaaaaaa
Login to view more

Abstract

The present invention relates to a nitride semiconductor laser device provided with a window layer on a light-emitting end face of the resonator which comprises an active layer of nitride semiconductor between the n-type nitride semiconductor layers and the p-type nitride semiconductor layers, in which at least the radiation-emitting end face of said resonator is covered by said window layer comprising monocrystalline nitride of general formula AlxGa1-x-yInyN, where 0≦x+y≦1, 0≦x≦1 and 0≦y<1, having a wider energy gap than that of the active layer and being formed at a low temperature so as not to damage said active layer. Formation of such a window layer improves significantly the performance of the nitride laser device according to the invention

Description

CROSS REFERENCE TO RELATED APPLICATIONS [0001] This application is a divisional application of U.S. patent application Ser. No. 10 / 519,501 filed on Dec. 27, 2004, currently pending, which was the National Stage of International Application No. PCT / PL2003 / 000061, filed on Jun. 26, 2003. The disclosures of U.S. patent application Ser. No. 10 / 519,501 and International Application No. PCT / PL2003 / 000061 are hereby incorporated by reference.BACKGROUND OF THE INVENTION [0002] 1. Field of the Invention [0003] The invention relates to a nitride semiconductor laser device and to a method for improving its performance leading to an extension of its lifetime. In particular the method according to the invention relates to providing a window layer on the radiation emitting end face of the resonator. Such a layer increases durability of the nitride semiconductor laser device according to the invention. [0004] 2. Description of the Related Art [0005] Lifetime of semiconductor laser devices depends ...

Claims

the structure of the environmentally friendly knitted fabric provided by the present invention; figure 2 Flow chart of the yarn wrapping machine for environmentally friendly knitted fabrics and storage devices; image 3 Is the parameter map of the yarn covering machine
Login to view more

Application Information

Patent Timeline
no application Login to view more
Patent Type & Authority Applications(United States)
IPC IPC(8): H01S5/16H01L21/208C30B7/00C30B9/00H01S5/028H01S5/323
CPCC30B9/00C30B29/403C30B29/406C30B7/005H01S5/164H01S5/32341H01S5/0281H01S5/30
Inventor DWILINSKI, ROBERTDORADZINSKI, ROMANGARCZYNSKI, JERZYSIERZPUTOWSKI, LESZEK P.KANBARA, YASUO
Owner AMMONO SP Z O O (PL)
Who we serve
  • R&D Engineer
  • R&D Manager
  • IP Professional
Why Eureka
  • Industry Leading Data Capabilities
  • Powerful AI technology
  • Patent DNA Extraction
Social media
Try Eureka
PatSnap group products

Browse by: Latest US Patents, China's latest patents, Technical Efficacy Thesaurus, Application Domain, Technology Topic.

© 2024 PatSnap. All rights reserved.Legal|Privacy policy|Modern Slavery Act Transparency Statement|Sitemap