Zinc-blende nitride semiconductor free-standing substrate, method for fabricating same, and light-emitting device employing same

• US 20090050928A1
• Filed: 12/12/2007
• Published: 02/26/2009
• Est. Priority Date: 08/22/2007
• Status: Active Grant

• Current Assignee: Hitachi Cable Limited (Proterial Ltd.)
• Original Assignee: Hitachi Cable Limited (Proterial Ltd.)
• Inventors: Fujikura, Hajime
• Granted Patent: US 8,030,682 B2
• Time in Patent Office: Days
• US Class Current: 257/103
• CPC Class Codes: H01L 21/02389 Nitrides
• CPC Class Codes: H01L 21/02395 Arsenides
• CPC Class Codes: H01L 21/02433 Crystal orientation
• CPC Class Codes: H01L 21/02458 Nitrides
• CPC Class Codes: H01L 21/02502 consisting of two layers
• CPC Class Codes: H01L 21/0254 Nitrides
• CPC Class Codes: H01L 21/0262 Reduction or decomposition of gaseous compounds, e.g. CVD
• CPC Class Codes: H01L 31/1844 comprising ternary or quaternary compounds, e.g. Ga Al As, In Ga As P
• CPC Class Codes: H01L 31/1852 comprising a growth substrate not being an AIIIBV compound
• CPC Class Codes: H01L 33/12 with a stress relaxation structure, e.g. buffer layer
• CPC Class Codes: H01L 33/16 with a particular crystal structure or orientation, e.g. polycrystalline, amorphous or porous
• CPC Class Codes: H01L 33/32 containing nitrogen
• CPC Class Codes: H01S 2304/04 MOCVD or MOVPE
• CPC Class Codes: H01S 5/0206 Substrates, e.g. growth, shape, material, removal or bonding; specific crystal orientation H01S5/3202
• CPC Class Codes: H01S 5/0422 with n- and p-contacts on the same side of the active layer
• CPC Class Codes: H01S 5/32341 blue laser based on GaN or GaP
• CPC Class Codes: Y02E 10/544 Solar cells from Group III-V materials

Abstract

A zinc-blende nitride semiconductor free-standing substrate has a front surface and a back surface opposite the front surface. The distance between the front and back surfaces is not less than 200 μm. The area ratio of the zinc-blende nitride semiconductor to the front surface is not less than 95%.

Claims

1. A zinc-blende nitride semiconductor free-standing substrate, comprising:

a zinc-blende nitride semiconductor;

a front surface; and

a back surface opposite the front surface,

wherein a distance between the front surface and the back surface is not less than 200 μ

m, and wherein an area ratio of the zinc-blende nitride semiconductor to the front surface is not less than 95%.

2. The zinc-blende nitride semiconductor free-standing substrate according to claim 1, wherein:

an As concentration in a vicinity of the front surface is not more than 1×

10¹⁹ cm<sup>−

3</sup>.

3. The zinc-blende nitride semiconductor free-standing substrate according to claim 1, wherein:

a dislocation density in the front surface is not more than 7×

10⁶ cm<sup>−

2</sup>.

4. A zinc-blende nitride semiconductor free-standing substrate fabrication method, comprising the steps of:

forming a low-temperature buffer layer comprising a zinc-blende nitride semiconductor in a surface of a zinc-blende GaAs substrate;

forming a zinc-blende nitride semiconductor layer on the low-temperature buffer layer; and

after forming the zinc-blende nitride semiconductor layer, removing the GaAs substrate to form a zinc-blende nitride semiconductor free-standing substrate.

5. The zinc-blende nitride semiconductor free-standing substrate fabrication method according to claim 4, further comprising the step of:

before forming the low-temperature buffer layer, forming a protective layer on an opposite side of the GaAs substrate to a surface formed with the low-temperature buffer layer.

6. The zinc-blende nitride semiconductor free-standing substrate fabrication method according to claim 4, wherein:

a surface of the GaAs substrate comprises any of a (001) plane, a (111) A or B plane.

7. A light-emitting device, comprising:

a zinc-blende nitride semiconductor free-standing substrate comprising a zinc-blende nitride semiconductor, a front surface, and a back surface opposite the front surface, wherein a distance between the front surface and the back surface is not less than 200 μ

m, and wherein an area ratio of the zinc-blende nitride semiconductor to the front surface is not less than 95%; and

a light-emitting layer formed on the zinc-blende nitride semiconductor free-standing substrate.

8. The light-emitting device according to claim 7, wherein:

an As concentration in a vicinity of the front surface is not more than 1×

10¹⁹ cm<sup>−

3</sup>.

9. The light-emitting device according to claim 7, wherein:

a dislocation density in the front surface is not more than 7×

10⁶ cm<sup>−

2</sup>.

10. The light-emitting device according to claim 7, wherein:

the light-emitting layer emits green light.