Nitride semiconductor device comprising bonded substrate and fabrication method of the same

• US 8,030,665 B2
• Filed: 04/30/2008
• Issued: 10/04/2011
• Est. Priority Date: 07/08/2002
• Status: Expired due to Fees

• Current Assignee: Nichia Corporation
• Original Assignee: Nichia Corporation
• Inventors: Yamamoto, Masashi, Sakamoto, Keiji, Nagahama, Shinichi, Morita, Daisuke, Yanamoto, Tomoya, Sano, Masahiko
• Primary Examiner(s): Le; Thao
• Assistant Examiner(s): Ullah; Elias
• Application Number:
  US12/113,030
• Publication Number:
  US 20080296609A1
• Time in Patent Office: 1,252 Days
• Field of Search: 257/103, 257/79, 257/E33.001, 438/518, 438/602, 438/767
• US Class Current: 257/79
• CPC Class Codes: H01L 21/76251 using bonding techniques
• CPC Class Codes: H01L 2224/45144 Gold (Au) as principal constituent
• CPC Class Codes: H01L 2224/48091 Arched
• CPC Class Codes: H01L 2224/48247 connecting the wire to a bond pad of the item
• CPC Class Codes: H01L 2224/49171 Fan-out arrangements
• CPC Class Codes: H01L 2924/00 Indexing scheme for arrangements or methods for connecting or disconnecting semiconductor or solid-state bodies as covered by H01L24/00
• CPC Class Codes: H01L 2924/00014 the subject-matter covered by the group, the symbol of which is combined with the symbol of this group, being disclosed without further technical details
• CPC Class Codes: H01L 2924/01013 Aluminum [Al]
• CPC Class Codes: H01L 2924/01037 Rubidium [Rb]
• CPC Class Codes: H01L 2924/12032 Schottky diode
• CPC Class Codes: H01L 2924/3025 Electromagnetic shielding
• CPC Class Codes: H01L 33/0093 Wafer bonding; Removal of the growth substrate
• CPC Class Codes: H01L 33/32 containing nitrogen
• CPC Class Codes: H01L 33/44 characterised by the coatings, e.g. passivation layer or anti-reflective coating
• CPC Class Codes: H01L 33/483 Containers
• CPC Class Codes: H01L 33/508 having a non-uniform spatial arrangement or non-uniform concentration, e.g. patterned wavelength conversion layer, wavelength conversion layer with a concentration gradient of the wavelength conversion material
• CPC Class Codes: H01L 33/62 Arrangements for conducting electric current to or from the semiconductor body, e.g. lead-frames, wire-bonds or solder balls

Abstract

A substrate 1 for growing nitride semiconductor has a first and second face and has a thermal expansion coefficient that is larger than that of the nitride semiconductor. At least n-type nitride semiconductor layers 3 to 5, an active layer 6 and p-type nitride semiconductor layers 7 to 8 are laminated to form a stack of nitride semiconductor on the first face of the substrate 1. A first bonding layer including more than one metal layer is formed on the p-type nitride semiconductor layer 8. A supporting substrate having a first and second face has a thermal expansion coefficient that is larger than that of the nitride semiconductor and is equal or smaller than that of the substrate 1 for growing nitride semiconductor. A second bonding layer including more than one metal layer is formed on the first face of the supporting substrate. The first bonding layer 9 and the second bonding layer 11 are faced with each other and, then, pressed with heat to bond together. After that, the substrate 1 for growing nitride semiconductor is removed from the stack of nitride semiconductor so that a nitride semiconductor device is provided.

Claims

1. A nitride semiconductor device, comprising:

a substrate having two opposed main faces;

a bonding layer placed on one main face of said substrate;

a p-electrode on said bonding layer;

one or more p-type nitride semiconductor layers electronically connected to the p-electrode;

an active layer comprising at least a well layer of Al_aIn_bGa_1-a-bN, (0≦

a≦

1, 0≦

b≦

1, a+b≦

1), and a barrier layer of Al_cIn_dGa_1-c-dN, (0≦

c≦

1, 0≦

d≦

1, c+d≦

1), the active layer being on said p-type nitride semiconductor layers;

n-type nitride semiconductor layers on said active layer; and

an n-electrode electrically connected to one or more of said n-type nitride semiconductor layers;

wherein said p-type nitride semiconductor layers, said active layer and said n-type nitride semiconductor layers are sandwiched between said p-electrode and said n-electrode, and

wherein protrusions or recessions are formed on a surface of said n-type semiconductor layers, said surface being on a side where luminescence is extracted from.

2. The nitride semiconductor device according to claim 1, wherein a planar shape of said protrusions or recessions is round or polygonal.

3. The nitride semiconductor device according to claim 1, wherein a planar shape of said protrusions or recessions is a lattice or rectangular.

4. The nitride semiconductor device according to claim 1, wherein a cross sectional shape of said protrusions or recessions is a mesa or a reverse mesa.

5. The nitride semiconductor device according to claim 1, wherein said protrusions or recessions are formed on said surface of said n-type semiconductor layers exposed from said n-electrode.

6. The nitride semiconductor device according to claim 1, wherein an n-side insulating protection film is formed to coat said surface of n-type nitride semiconductor layers exposed from said n-electrode.

7. The nitride semiconductor device according to claim 1, wherein said n-side insulating protection film comprises SiO₂, Al₂O₃, ZrO₂ or TiO₂.

8. The nitride semiconductor device according to claim 1, wherein said p-electrode and said n-electrode are arranged on the opposite to each other so as not to be overlapped when observed in the layered direction of said p-type and n-type nitride semiconductor layers.

9. The nitride semiconductor device according to claim 1, wherein a p-side insulating protection film made of a monolayer or a multi-layer film is formed between said bonding layer and said p-type nitride semiconductor layers.

10. The nitride semiconductor device according to claim 9, wherein a metal film is formed between said bonding layer and said p-side insulating protection film.

11. The nitride semiconductor device according to claim 9, wherein said p-side insulating protection film is made of a monolayer or a multi-layer film including SiO₂, Al₂O₃, ZrO₂ or TiO₂.

12. A nitride semiconductor device, comprising:

a substrate having two opposed main faces;

a bonding layer placed on one main face of said substrate;

a p-electrode on said bonding layer;

one or more p-type nitride semiconductor layers electrically connected to the p-electrode;

a p-side insulating protection film made of a monolayer or a multi-layer film and formed between said bonding layer and said p-type nitride semiconductor layers;

an active layer comprising at least a well layer of Al_aIn_bGa_1-a-bN, (0≦

a≦

1, 0≦

b≦

1, a+b<

1), and a barrier layer of Al_cIn_dGa_1-c-dN, (0≦

c≦

1, 0≦

d≦

1, c+d≦

1), the active layer being on said p-type nitride semiconductor layers;

n-type nitride semiconductor layers on said active layer; and

an n-electrode electrically connected to one or more of said n-type nitride semiconductor layers;

wherein said p-type nitride semiconductor layers, said active layer and said n-type nitride semiconductor layers are sandwiched between said p-electrode and said n-electrode,

wherein protrusions or recessions are formed on a surface of said n-type semiconductor layers, said surface being on a side where luminescence is extracted from.

13. The nitride semiconductor device according to claim 12, wherein said protrusions or recessions are formed on said surface of said n-type semiconductor layers exposed from said n-electrode.

14. The nitride semiconductor device according to claim 13, wherein a planar shape of said protrusions or recessions is round or polygonal.

15. The nitride semiconductor device according to claim 14, said p-electrode and said n-electrode are arranged on the opposite to each other so as not to be overlapped when observed in the layered direction of said p-type and n-type nitride semiconductor layers.

16. The nitride semiconductor device according to claim 15, wherein a metal film is formed between said bonding layer and said p-side insulating protective film.