Light-emitting aluminum gallium indium nitride compound semiconductor device having an improved luminous intensity

• US 6,265,726 B1
• Filed: 08/24/1999
• Issued: 07/24/2001
• Est. Priority Date: 03/22/1994
• Status: Expired due to Term

• Current Assignee: Toyoda Gosei Company Limited (Toyota Motor Corporation)
• Original Assignee: Toyoda Gosei Company Limited (Toyota Motor Corporation)
• Inventors: Shibata, Naoki, Kato, Hisaki, Koike, Masayoshi, Sassa, Michinari, Asai, Makoto, Manabe, Katsuhide, Yamazaki, Shiro
• Primary Examiner(s): Tran, Minh Loan
• Application Number:
  US09/379,621
• Time in Patent Office: 700 Days
• Field of Search: 257/13, 257/87, 257/94, 257/101, 257/102, 257/103, 257/12, 257/96, 372/43, 372/45
• US Class Current: 257/13
• CPC Class Codes: H01L 33/0025 comprising only AIIIBV compounds
• CPC Class Codes: H01L 33/007 comprising nitride compounds
• CPC Class Codes: H01L 33/32 containing nitrogen
• CPC Class Codes: H01L 33/325 characterised by the doping materials
• CPC Class Codes: H01L 33/38 with a particular shape
• CPC Class Codes: H01L 33/382 the electrode extending partially in or entirely through the semiconductor body
• CPC Class Codes: H01L 33/385 the electrode extending at least partially onto a side surface of the semiconductor body
• CPC Class Codes: H01L 33/40 Materials therefor

Abstract

A light-emitting semiconductor device (10) consecutively includes a sapphire substrate (1), an AlN buffer layer (2), a silicon (Si) doped GaN n⁺-layer (3) of high carrier (n-type) concentration, a Si-doped (Al_x3Ga_1−x3)_y3In_1−y3N n⁺-layer (4) of high carrier (n-type) concentration, a zinc (Zn) and Si-doped (Al_x2Ga_1−x2)_y2In_1−y2N emission layer (5), and a Mg-doped (Al_x1Ga_1−x1)_y1In_1−y1N p-layer (6). The AlN layer (2) has a 500 Å thickness. The GaN n⁺-layer (3) has about a 2.0 μm thickness and a 2×10¹⁸/cm³ electron concentration. The n⁺-layer (4) has about a 2.0 μm thickness and a 2×10¹⁸/cm³ electron concentration. The emission layer (5) has about a 0.5 μm thickness. The p-layer 6 has about a 1.0 μm thickness and a 2×10¹⁷/cm³ hole concentration. Nickel electrodes (7, 8) are connected to the p-layer (6) and n⁺-layer (4), respectively. A groove (9) electrically insulates the electrodes (7, 8). The composition ratio of Al, Ga, and In in each of the layers (4, 5, 6) is selected to meet the lattice constant of GaN in the n⁺-layer (3). The LED (10) is designed to improve luminous intensity and to obtain purer blue color.

Claims

1. A light-emitting semiconductor device comprising:

an N⁺-layer of N-type conduction of group III nitride compound semiconductor;

an N-layer of N-type conduction of group III nitride compound semiconductor satisfying the formula Al_x2Ga_y2In<sub>1−

x2−

y2</sub>N, where 0≦

x2≦

1, 0≦

y2≦

1, and 0≦

x2+y2≦

1 with a low electron concentration formed on said N⁺-layer, said N-layer having a valence band;

an emission layer of group III nitride compound semiconductor satisfying the formula Al_x3Ga_y3In<sub>1−

x3−

y3</sub>N, where 0≦

x3≦

1, 0≦

y3≦

1, and 0≦

x3+y3≦

1;

a P-layer of P-type conduction of group III nitride compound semiconductor satisfying the formula Al_x4Ga_y4In<sub>1−

x4−

y4</sub>N, where 0≦

x4≦

1, 0≦

y4≦

1, and 0≦

x4+y4≦

1, said P-layer having a conduction band;

a P-electrode emission layer, and

an N-electrode;

wherein a band width of said N-layer is smaller than a band width of said P-layer and an electrical potential barrier of the valence band of said N-layer is lower than an electrical potential barrier of the conduction band of said P-layer.

2. A light-emitting semiconductor device according to claim 1, wherein said N⁺-layer is doped with Si.

3. A light-emitting semiconductor device according to claim 2, wherein said P-layer is doped with Mg.

4. A light-emitting semiconductor device according to claim 1, wherein said P-layer is doped with Mg.

5. A light-emitting semiconductor device according to claim 1, wherein said N-electrode is Ni.

6. A light-emitting semiconductor device according to claim 1, wherein said P-electrode is Ni.

7. A light-emitting semiconductor device according to claim 1, further comprising:

a sapphire substrate, and

a buffer layer formed on said sapphire substrate, said N⁺-layer being formed on said buffer layer.

8. A light-emitting semiconductor device according to claim 1, wherein said N⁺-layer is formed with GaN.

9. A light-emitting semiconductor device comprising:

an N⁺-layer of N-type conduction of group III nitride compound semiconductor, the N⁺-layer having formed thereon an N-layer of N-type conduction of group III nitride compound semiconductor satisfying the formula Al_x2Ga_y2In<sub>1−

x2−

y2</sub>N, where 0≦

x2≦

1, 0≦

y2≦

1, and 0≦

x2+y2≦

1 with a low electron concentration, the N-layer having a valence band;

an emission layer of group III nitride compound semiconductor satisfying the formula Al_x3Ga_y3In<sub>1−

x3−

y3</sub>N, where 0≦

x3≦

1, 0≦

y3≦

1, and 0≦

x3+y3≦

1, the emission layer being formed on the N-layer;

a P-layer of P-type conduction of group III nitride compound semiconductor satisfying the formula Al_x4Ga_y4In<sub>1−

x4−

y4</sub>N, where 0≦

x4≦

1, 0≦

y4≦

1, and 0≦

x4+y4≦

1, the P-layer being formed on the emission layer and having a conduction band formed thereon;

a P-electrode; and

an N-electrode;

wherein a band width of the N-layer is smaller than a band width of the P-layer and an electrical potential barrier of the valence band of the N-layer is lower than an electrical potential barrier of the conduction band of the P-layer.