Nitride semiconductor laser device and method of manufacturing the same

• US 20070098030A1
• Filed: 11/02/2006
• Published: 05/03/2007
• Est. Priority Date: 11/03/2005
• Status: Abandoned Application

• Current Assignee: Samsung Electronics Co. Ltd.
• Original Assignee: Samsung Electronics Co. Ltd.
• Inventors: Ha, Kyoung-ho, Ryu, Han-youl
• Application Number:
  US11/591,515
• Publication Number:
  US 20070098030A1
• Time in Patent Office: Days
• US Class Current: 372/43.01
• CPC Class Codes: B82Y 20/00 Nanooptics, e.g. quantum optics or photonic crystals
• CPC Class Codes: H01S 5/04253 having specific optical properties, e.g. transparent electrodes
• CPC Class Codes: H01S 5/04254 characterised by the shape
• CPC Class Codes: H01S 5/20 Structure or shape of the semiconductor body to guide the optical wave ; Confining structures perpendicular to the optical axis, e.g. index or gain guiding, stripe geometry, broad area lasers, gain tailoring, transverse or lateral reflectors, special cladding structures, MQW barrier reflection layers
• CPC Class Codes: H01S 5/2009 by using electron barrier layers
• CPC Class Codes: H01S 5/22 having a ridge or stripe structure
• CPC Class Codes: H01S 5/2214 based on oxides or nitrides
• CPC Class Codes: H01S 5/3214 comprising materials from other groups of the periodic system than the materials of the active layer, e.g. ZnSe claddings and GaAs active layer
• CPC Class Codes: H01S 5/3216 quantum well or superlattice cladding layers
• CPC Class Codes: H01S 5/34333 with a well layer based on Ga(In)N or Ga(In)P, e.g. blue laser

Abstract

A semiconductor laser device is provided. The semiconductor laser device includes a substrate, and an n-material layer, an n-clad layer, an n-light waveguide layer, an active region, a nitride semiconductor layer, a metal layer and a metal-based clad layer sequentially formed on the substrate. The metal layer and the metal-based clad layer have a ridge shape and a current blocking layer is formed on sidewalls of the metal layer and the metal-based clad layer and an exposed surface of the nitride semiconductor layer. A p-electrode layer is formed on the ridge shaped metal layer and the current blocking layer. The semiconductor laser device uses the metal-based clad layer instead of Al_xIn_yGa_1-x-yN-based p-clad layer, thus preventing degradation of the active region. The semiconductor laser device also includes the thin metal layer between the metal-based clad layer and a p-GaN material of the nitride semiconductor layer, thus reducing contact resistance therebetween. Thus, it is possible to fabricate a high power, low voltage semiconductor laser device having a visible light wavelength.

Claims

1. A semiconductor laser device comprising:

an active region;

a nitride semiconductor layer formed on the active region; and

a ridge-shaped metal layer formed on the nitride semiconductor layer.

2. The device of claim 1, wherein the metal layer has a thickness less than approximately 1,000 nm.

3. The device of claim 1, further comprising a current blocking layer covering sidewalls of the ridge-shaped metal layer and a surface of the nitride semiconductor layer exposed on both sides of the ridge-shaped metal layer.

4. The device of claim 1, wherein the active region has a single quantum well (SQW) or multiple quantum well (MQW) structure.

5. The device of claim 4, wherein the quantum well is made from one of GaN, AlGaN, InGaN and AllnGaN.

6. The device of claim 1, wherein the nitride semiconductor layer is formed in a thickness of approximately 1 to 500 nm.

7. The device of claim 1, further comprising a ridge-shaped metal-based clad layer formed on the metal layer.

8. The device of claim 7, wherein the metal-based clad layer is made of conductive metal oxide.

9. The device of claim 7, wherein the metal-based clad layer is made of conductive metal nitride.

10. The device of claim 7, further comprising a current blocking layer formed on sidewalls of the ridge-shaped metal layer and metal-clad layer and a surface of the nitride semiconductor layer exposed on both sides of the ridge-shaped metal layer and metal-clad layer.

11. The device of claim 3, wherein the current blocking layer is formed of at least one of an insulating dielectric material and oxide containing at least one element selected from the group consisting of silicon (Si), aluminum (Al), zirconium (Zr), tantalum (Ta), Hf, Mn, and titanium (Ti).

12. The device of claim 7, wherein the metal layer is formed in a thickness of approximately 1 to 100 nm.

13. The device of claim 1, wherein the metal layer is formed of at least one of a metal selected from the group consisting of palladium (Pd), platinum (Pt), nickel (Ni), gold (Au), ruthenium (Ru), silver (Ag), and lanthanide series metals and an alloy or solid solution containing at least one of the metals.

14. The device of claim 1, wherein the metal layer has at least one layer formed of a metal or an alloy or solution containing at least one metal selected from the group consisting of palladium (Pd), platinum (Pt), nickel (Ni), gold (Au), ruthenium (Ru), silver (Ag), and lanthanide series metals.

15. The device of claim 7, wherein the metal-based clad layer is formed in a thickness of approximately 50 to 1,000 nm.

16. The device of claim 8, wherein the conductive metal oxide consists of oxygen (O) and at least one metal selected from the group consisting of indium (In), tin (Sn), zinc (Zn), gallium (Ga), cadmium (Cd), magnesium (Mg), beryllium (Be), Ag, molybdenum (Mo), vanadium (V), copper (Cu), iridium (Ir), rhodium (Rh), Ru, tungsten (W), cobalt (Co), Ni, manganese (Mn), Al, and lanthanide series metals.

17. The device of claim 8, wherein the conductive metal oxide contains In and Sn together with oxygen as its main elements.

18. The device of claim 9, wherein the conductive metal nitride contains titanium (Ti) and nitrogen (N).

19. The device of claim 7, wherein the metal-based clad layer further includes an additional element to adjust the electrical characteristics.

20. The device of claim 19, wherein the additional element is at least one selected from the group consisting of Mg, Ag, Zn, scandium (Sc), hafnium (Hf), Zr, tellurium (Te), selenium (Se), Ta, W, niobium (Nb), Cu, Si, Ni, Co, Mo, chrome (Cr), Mn, mercury (Hg), praseodymium (Pr), and lanthanide (Ln) series metals.

24. The device of claim 8, wherein the conductive metal oxide contains In and Sn together with oxygen as its main elements.

21. A method of fabricating a semiconductor laser device comprising:

forming an active region;

forming a nitride semiconductor layer on the active region;

forming a metal layer on the light waveguide layer;

etching the metal layer to form a ridge; and

forming a current blocking layer covering sidewalls of the ridge and a surface of the nitride semiconductor layer exposed on both sides of the ridge.

22. The method of claim 21, further comprising:

forming a metal-based clad layer on the metal layer;

etching the metal layer and the metal-based clad layer to form a ridge;

forming a current blocking layer covering sidewalls of the ridge and a surface of the nitride semiconductor layer exposed on both sides of the ridge; and

forming a p-electrode layer on the ridge and the current blocking layer.

23. The method of claim 22, wherein the metal-based clad layer is made of one of conductive metal oxide and conductive metal nitride.