Silicon carbide light emitting diode and a method for the same

• US 5,243,204 A
• Filed: 05/17/1991
• Issued: 09/07/1993
• Est. Priority Date: 05/18/1990
• Status: Expired due to Term

• Current Assignee: Sharp Kabushiki Kaisha (Hon Hai Precision Industry Co., Ltd.)
• Original Assignee: Sharp Kabushiki Kaisha (Hon Hai Precision Industry Co., Ltd.)
• Inventors: Suzuki, Akira, Fujii, Yoshihisa, Furukawa, Katsuki
• Primary Examiner(s): WOJCIECHOWICZ, EDWARD JOSEPH
• Application Number:
  US07/702,819
• Time in Patent Office: 844 Days
• Field of Search: 357/17, 257/77, 257/103, 257/613, 257/656, 257/657
• US Class Current: 257/77
• CPC Class Codes: H01L 33/0054 for devices with an active region comprising only group IV elements
• CPC Class Codes: H01L 33/34 containing only elements of Group IV of the Periodic Table

Abstract

There are provided silicon carbide light emitting diodes having a p-n junction which is constituted by a p-type silicon carbide single-crystal layer and an n-type silicon carbide single-crystal layer formed thereon. In cases where light emission caused by recombination of free excitons is substantially utilized, at least a part of the n-type silicon carbide layer adjacent to the interface of the p-n junction is doped with a donor impurity at a concentration of 5×10¹⁶ cm^-3 or lower. In cases where light emission caused by acceptor-associated recombination is substantially utilized, the p-type silicon carbide layer is doped with an acceptor impurity and at least a part of the n-type silicon carbide layer adjacent to the interface of the p-n junction is doped with a donor impurity at a concentration of 1×10¹⁸ cm^-3 or higher. Also provided are a method for producing such silicon carbide light emitting diodes and a method for producting another silicon carbide light emitting diode.

Claims

1. A silicon carbide light emitting diode comprising an n-type silicon carbide single-crystal substrate, a second n-type silicon carbide single-crystal layer formed on the substrate, a first n-type silicon carbide single-crystal layer formed on the second n-type silicon carbide single-crystal layer and a p-type silicon carbide single-crystal layer formed on the first n-type silicon carbide single-crystal layer, wherein

the second n-type layer contains a donor impurity at a concentration of higher than 5×

10¹⁶ cm^-3, and the first n-type layer contains a donor impurity at a concentration of 5×

10¹⁶ cm^-3 or lower.

2. A silicon carbide light emitting diode according to claim 1, wherein the silicon carbide single crystal is of a polytype selected from the group consisting of 4H, 6H, 15R, 21R, and 3C.

3. A silicon carbide light emitting diode according to claim 1, further comprising a substrate made of a silicon carbide single crystal in the hexagonal system, the p-type or n-type silicon carbide layer being formed on the substantial (0001)C plane of the substrate.

4. A silicon carbide light emitting diode according to claim 1, further comprising a substrate made of a silicon carbide single crystal in the cubic system, the p-type or n-type silicon carbide layer being formed on the substantial (111)C plane of the substrate.

5. A silicon carbide light emitting diode according to claim 1, wherein a surface of the n-type silicon carbide substrate on which the second n-type silicon carbide single-crystal layer is formed is inclined from the [0001] direction toward the <

1120>

direction at an angle of 2 to 15 degrees.

6. A silicon carbide light emitting diode according to claim 1, wherein the donor impurity is nitrogen.

7. A silicon carbide light emitting diode comprising an n-type silicon carbide single-crystal substrate, a second n-type silicon carbide single-crystal layer formed on the substrate, a first n-type silicon carbide single-crystal layer formed on the second n-type silicon carbide single-crystal layer and a p-type silicon carbide single-crystal layer formed on the first n-type silicon carbide single-crystal layer, wherein

the p-type silicon carbide single-crystal layer contains an acceptor impurity, the second n-type layer contains a donor impurity at a concentration of lower than 1×

10¹⁸ cm^-3, and the first n-type layer contains a donor impurity at a concentration of 1×

10¹⁸ cm^-3 or higher.

8. A silicon carbide light emitting diode according to claim 7, wherein the silicon carbide single crystal is of a polytype selected from the group consisting of 4H, 6H, and 3C.

9. A silicon carbide light emitting diode according to claim 7, further comprising a substrate made of a silicon carbide single crystal in the hexagonal system, the p-type or n-type silicon carbide layer being formed on the substantial (0001)C plane of the substrate.

10. A silicon carbide light emitting diode according to claim 7, further comprising a substrate made of a silicon carbide single crystal in the cubic system, the p-type or n-type silicon carbide layer being formed on the substantial (111)C plane of the substrate.

11. A silicon carbide light emitting diode according to claim 7, wherein a surface of the n-type silicon carbide single-crystal substrate on which the second nj-type silicon carbide single-crystal layer is formed is inclined from the [0001] direction toward the <

1120>

direction at an angle of 2 to 15 degrees.

12. A silicon carbide light emitting diode according to claim 7, wherein the donor impurity is nitrogen, and the acceptor impurity is aluminum.