Method for producing transparent conductive layer comprising TIO2 and method for producing semiconductor light-emitting element utilizing said method for producing transparent conductive layer

• US 8,716,047 B2
• Filed: 08/31/2009
• Issued: 05/06/2014
• Est. Priority Date: 09/01/2008
• Status: Active Grant

• Current Assignee: Kanagawa Institute of Industrial Science and Technology, Toyoda Gosei Company Limited (Toyota Motor Corporation)
• Original Assignee: Kanagawa Academy of Science and Technology, Toyoda Gosei Company Limited (Toyota Motor Corporation)
• Inventors: Goshonoo, Koichi, Moriyama, Miki, Hitosugi, Taro, Hasegawa, Tetsuya, Kasai, Junpei
• Primary Examiner(s): Quach, Tuan N.
• Application Number:
  US12/585,015
• Publication Number:
  US 20100062558A1
• Time in Patent Office: 1,709 Days
• Field of Search: 438/46, 438/604, 438/608, 438/609, 257/E21.159
• US Class Current: 438/46
• CPC Class Codes: H01L 33/0095 Post-treatment of devices, e.g. annealing, recrystallisation or short-circuit elimination
• CPC Class Codes: H01L 33/44 characterised by the coatings, e.g. passivation layer or anti-reflective coating

Abstract

When a p-layer 4 composed of GaN is maintained at ordinary temperature and TNO is sputtered thereon by an RF magnetron sputtering method, a laminated TNO layer 5 is in an amorphous state. Then, there is included a step of thermally treating the amorphous TNO layer in a reduced-pressure atmosphere where hydrogen gas is substantially absent to thereby crystallize the TNO layer. At the sputtering, an inert gas is passed through together with oxygen gas, and volume % of the oxygen gas contained in the gas passed through is 0.10 to 0.15%. In this regard, oxygen partial pressure is 5×10⁻³ Pa or lower. The temperature of the thermal treatment is 500° C. for about 1 hour.

Claims

1. A method for producing a transparent conductive electrode comprising TiO₂ contacting with a p-type Group III nitride-based compound semiconductor layer, the method comprising:

laminating an amorphous TiO₂ layer on the p-type Group III nitride-based compound semiconductor layer, said laminating being performed by a sputtering method and without heating; and

thermally treating the amorphous TiO₂ layer at 400°

C. to 800°

C. to crystallize the amorphous TiO₂ layer and form an anatase TiO₂ layer,

wherein said sputtering method comprises passing through a gas including oxygen and an inert gas, and

wherein the p-type Group III nitride-based compound semiconductor layer is cooled to a temperature equal to or lower than a room temperature for laminating the amorphous TiO₂ layer after a film deposition of the amorphous TiO₂ layer.

2. The method according to claim 1, wherein the anatase TiO₂ layer is doped with one or more elements selected from the group consisting of Nb, Ta, Mo, As, Sb, Al, and W.

3. The method according to claim 1, wherein the laminating of the amorphous TiO₂ layer is performed in the inert gas passed through together with the oxygen, and a ratio of the oxygen in the gas passed through is 0.05 to 0.20% by volume.

4. The method according to claim 3, wherein the ratio of the oxygen in the gas passed through is 0.10% to 0.15% by volume.

5. The method according to claim 1, further comprising:

patterning the amorphous TiO₂.

6. The method according to claim 1, further comprising:

laminating the Group III nitride-based compound semiconductor layer on a substrate.

7. The method according to claim 6, further comprising:

forming a buffer layer that comprises AlN on the substrate, and laminating an n-type Group III nitride-based compound semiconductor layer on the buffer layer.

8. The method according to claim 7, wherein the n-type Group III nitride-based compound semiconductor layer comprises a contact layer comprising n-GaN and a clad layer formed by multiple laminations of InGaN and GaN.

9. The method according to claim 7, further comprising:

laminating an active layer on the n-type Group III nitride-based compound semiconductor layer.

10. The method according to claim 9, wherein the active layer comprises a multi-quantum well structure including multiple laminations of AlGaN and InGaN.

11. The method according to claim 9, further comprising:

laminating a p-type Group III nitride-based compound semiconductor layer on the active layer.

12. The method according to claim 11, wherein the p-type Group III nitride-based compound semiconductor layer comprises a clad layer formed by multiple laminations of InGaN and AlGaN and a contact layer comprising p-GaN.

13. The method according to claim 11, further comprising:

thermally treating a laminate structure comprising the n-type Group III nitride-based compound semiconductor layer, the active layer, and the p-type Group III nitride-based compound semiconductor layer, prior to said thermally treating the amorphous TiO₂ layer.

14. The method according to claim 13, further comprising:

sputtering the laminate structure prior to said thermally treating the anatase TiO₂ layer.

15. The method according to claim 13, wherein, in the sputtering method, the oxygen is mixed into the inert gas as a carrier gas.

16. The method according to claim 11, further comprising:

etching parts of the n-type Group III nitride-based compound semiconductor layer, the active layer, and the p-type Group III nitride-based compound semiconductor layer to partially expose the n-type Group III nitride-based compound semiconductor layer.

17. The method according to claim 11, further comprising:

forming a p-pad electrode on the anatase TiO₂ layer; and

forming an n-pad electrode on an exposed portion of the n-type Group III nitride-based compound semiconductor layer.

18. The method according to claim 1, further comprising laminating a ZnO layer that is doped with Al, the anatase TiO₂ layer being doped with Nb.

19. The method according to claim 1, wherein the ratio of the oxygen in the gas passed through is in a range from 0.125% to 0.15% by volume.

20. The method according to claim 1, wherein, in said sputtering method, the gas is passed through a chamber, and

wherein a base pressure in the chamber is lowered when the oxygen is passed through the chamber.