Nitride Semiconductor Ultraviolet Light-Emitting Element and Nitride Semiconductor Ultraviolet Light-Emitting Device

• US 20170263817A1
• Filed: 04/03/2015
• Published: 09/14/2017
• Est. Priority Date: 04/03/2015
• Status: Active Grant

• Current Assignee: Nikkiso Company Limited
• Original Assignee: Soko Kagaku Co Ltd
• Inventors: Hirano, Akira, Ippommatsu, Masamichi
• Granted Patent: US 9,812,611 B2
• Time in Patent Office: Days
• CPC Class Codes: H01L 21/28 Manufacture of electrodes on semiconductor bodies using processes or apparatus not provided for in groups H01L21/20 - H01L21/268 etching for patterning the electrodes H01L21/311, H01L21/3213; multistep manufacturing processes for data storage electrodes H01L29/4011
• CPC Class Codes: H01L 21/288 from a liquid, e.g. electrolytic deposition
• CPC Class Codes: H01L 2224/14 of a plurality of bump connectors
• CPC Class Codes: H01L 2224/16225 the item being non-metallic, e.g. insulating substrate with or without metallisation
• CPC Class Codes: H01L 2933/0016 relating to electrodes
• CPC Class Codes: H01L 33/24 of the light emitting region, e.g. non-planar junction
• CPC Class Codes: H01L 33/32 containing nitrogen
• CPC Class Codes: H01L 33/38 with a particular shape
• CPC Class Codes: H01L 33/387 with a plurality of electrode regions in direct contact with the semiconductor body and being electrically interconnected by another electrode layer
• CPC Class Codes: H01L 33/44 characterised by the coatings, e.g. passivation layer or anti-reflective coating
• CPC Class Codes: H01L 33/46 Reflective coating, e.g. dielectric Bragg reflector

Abstract

There is provided a nitride semiconductor ultraviolet light-emitting element capable of efficiently releasing a waste heat generated in an ultraviolet light emitting operation. The nitride semiconductor ultraviolet light-emitting element includes a semiconductor laminated portion 11 having an n-type AlGaN layer 6, an active layer 7 of an AlGaN layer, and p-type AlGaN layers 9 and 10; an n electrode 13; a p electrode 12; a protective insulating film 14, and a first plated electrode 15 formed by a wet plating method and composed of copper or alloy containing copper as a main component. The semiconductor laminated portion 11 is formed in a first region R1, and the p electrode is formed on the portion 11. An upper surface of the n-type AlGaN-based semiconductor layer 6 is exposed in a second region, and the n electrode 13 is formed on the upper surface. The protective insulating film 14 has openings for exposing at least one part of the n electrode 13 and at least one part of the p electrode 12. The first plated electrode 15 is spaced apart from the exposed surface of the n electrode 13 and covers a whole upper surface and a whole outer side surface of the first region R1, and a part of the second region R2 which is in contact with the first region R1.

Claims

1. A nitride semiconductor ultraviolet light-emitting element comprising:

a semiconductor laminated portion including, in a laminated manner, a first semiconductor layer having one or more n-type AlGaN-based semiconductor layers, an active layer having one or more AlGaN-based semiconductor layers having an AlN mole fraction of zero or more, and a second semiconductor layer having one or more p-type AlGaN-based semiconductor layers;

an n electrode including one or more metal layers;

a p electrode including one or more metal layers;

a protective insulating film; and

a first plated electrode which is in contact with an exposed surface of the p electrode which is not covered with the protective insulating film, wherein

referring to a region that the one nitride semiconductor ultraviolet light-emitting element is formed in a plane parallel to a surface of the semiconductor laminated portion as an element region, the semiconductor laminated portion includes the active layer and the second semiconductor layer laminated on the first semiconductor layer in a first region which is a part of the element region, and does not include the active layer and the second semiconductor layer laminated on the first semiconductor layer in a second region in the element region other than the first region,

the first region has a recess surrounding the second region from three directions in planarly-viewed shape,

the second region continuously has a recessed region surrounded by the recess of the first region, and a periphery region other than the recessed region,

the n electrode is formed on the first semiconductor layer in the second region and covers the recessed region and the periphery region,

the p electrode is formed on an uppermost surface of the second semiconductor layer,

the protective insulating film covers at least a whole outer side surface of the semiconductor laminated portion in the first region, an upper surface of the first semiconductor layer provided between the first region and the n electrode, and an upper surface and a side surface of an outer edge portion of the n electrode including a portion at least facing the first region, and does not cover and exposes at least one part of a surface of the n electrode and at least one part of a surface of the p electrode, and

the first plated electrode is composed of copper or alloy containing copper as a main component, formed by wet plating method, spaced apart from the exposed surface of the n electrode which is not covered with the protective insulating film, and covers a whole upper surface of the first region including the exposed surface of the p electrode, the whole outer side surface of the first region covered with the protective insulating film, and a boundary region which is a part in the second region and is in contact with the first region.

2. The nitride semiconductor ultraviolet light-emitting element according to claim 1, wherein

the recessed region of the second region is entirely covered with the first plated electrode through the protective insulating film.

3. The nitride semiconductor ultraviolet light-emitting element according to claim 1, wherein

the first plated electrode is spaced apart from the exposed surface of the n electrode which is not covered with the protective insulating film, by 75 μ

m or more.

4. The nitride semiconductor ultraviolet light-emitting element according to claim 1, wherein

the protective insulating film further covers an upper surface and a side surface around an outer edge potion of the p electrode, and an exposed surface of the uppermost surface of the second semiconductor layer which is not covered with the p electrode.

5. The nitride semiconductor ultraviolet light-emitting element according to claim 1, further comprising a second plated electrode formed at least on the exposed surface of the n electrode which is not covered with the protective insulating film, formed by the wet plating method and composed of copper or alloy containing copper as a main component, wherein

the first plated electrode and the second plated electrode are spaced apart from each other.

6. The nitride semiconductor ultraviolet light-emitting element according to claim 5, wherein

surfaces of the first plated electrode and the second plated electrode are planarized, and

heights of the surfaces vertical to the surface of the semiconductor laminated portion are level with each other.

7. The nitride semiconductor ultraviolet light-emitting element according to claim 5, wherein

a spaced distance between the first plated electrode and the second plated electrode is 75 μ

m or more.

8. The nitride semiconductor ultraviolet light-emitting element according to claim 5, wherein

a single-layer or multiple-layer plated metal film including gold at least on an uppermost layer is formed on each of the surfaces of the first plated electrode and the second plated electrode.

9. The nitride semiconductor ultraviolet light-emitting element according to claim 1, wherein

an outer periphery of the first plated electrode is entirely located on the n electrode through the protective insulating film.

10. The nitride semiconductor ultraviolet light-emitting element according to claim 1, wherein

the first plated electrode is formed and filled in a dent in the recessed region surrounded by the outer side surface of the semiconductor laminated portion in the first region, and an upper surface of the first plated electrode is wholly flat.

11. The nitride semiconductor ultraviolet light-emitting element according to claim 1, wherein

the wet plating method includes an electrolytic plating method, and a power-feeding seed film used in the electrolytic plating method is formed between the protective insulating film and the first plated electrode.

12. The nitride semiconductor ultraviolet light-emitting element according to claim 11, wherein

the protective insulating film includes a transparent insulating film composed of an insulating material which transmits ultraviolet light emitted from the active layer, and

an ultraviolet light refractive layer is formed between the protective insulating film and the seed film to reflect the ultraviolet light at a reflectivity higher than an ultraviolet light reflectivity of the seed film.

13. The nitride semiconductor ultraviolet light-emitting element according to claim 1, wherein

the protective insulating film includes a transparent insulating film composed of an insulating material which transmits ultraviolet light emitted from the active layer, and

an opaque insulating film is formed at least one part on the protective insulating film between the first plated electrode and the exposed surface of the n electrode, and composed of an insulating material which does not transmit the ultraviolet light emitted from the active layer.

14. The nitride semiconductor ultraviolet light-emitting element according to claim 1, wherein

the protective insulating film includes an opaque insulating film composed of an insulating material which does not transmit the ultraviolet light emitted from the active layer.

15. A nitride semiconductor ultraviolet light-emitting device comprising:

a base including a metal film on a surface of an insulating base material, the metal film having a predetermined planarly-viewed shape and including two or more electrode pads; and

the nitride semiconductor ultraviolet light-emitting element according to claim 1 mounted on the base with the first plated electrode facing the electrode pad,

wherein the first plated electrode is electrically and physically connected to the opposed electrode pad.

16. The nitride semiconductor ultraviolet light-emitting device according to claim 15, wherein

the nitride semiconductor ultraviolet light-emitting element further includes a second plated electrode formed at least on an exposed surface of the n electrode which is not covered with the protective insulating film, formed by the wet plating method, and composed of copper or alloy containing copper as a main component,

the first plated electrode and the second plated electrode are spaced apart from each other, and

the first plated electrode is electrically and physically connected to the one electrode pad, and the second plated electrode is electrically and physically connected to the other electrode pad, in the one nitride semiconductor ultraviolet light-emitting element.

17. The nitride semiconductor ultraviolet light-emitting device according to claim 16, wherein

the base includes a plurality of couples of electrode pads which each include a first electrode pad and at least one second electrode pad electrically separated from the first electrode pad,

a plurality of the nitride semiconductor ultraviolet light-emitting elements are mounted on the base, and

the first plated electrode in the one nitride semiconductor ultraviolet light-emitting element is electrically and physically connected to the first electrode pad in the one couple of electrode pads, and the second plated electrode in the one nitride semiconductor ultraviolet light-emitting element is electrically and physically connected to the second electrode pad in the one couple of electrode pads.