Nitride compound semiconductor, nitride compound semiconductor light emitting device and method of manufacturing the same

• US 20030138976A1
• Filed: 01/30/2003
• Published: 07/24/2003
• Est. Priority Date: 03/12/1999
• Status: Active Grant

• Current Assignee: Kabushiki Kaisha Toshiba (Toshiba Corporation)
• Original Assignee: Kabushiki Kaisha Toshiba (Toshiba Corporation)
• Inventors: Sugawara, Hideto
• Granted Patent: US 6,881,601 B2
• Time in Patent Office: Days
• US Class Current: 438/1
• CPC Class Codes: H01L 33/007 comprising nitride compounds
• CPC Class Codes: H01L 33/32 containing nitrogen
• CPC Class Codes: H01S 5/32308 emitting light at a wavelength less than 900 nm
• CPC Class Codes: H01S 5/32341 blue laser based on GaN or GaP

Abstract

A nitride compound semiconductor light-emitting device having a stack of layers including an active layer for a light emitting device and a method of manufacturing the device is disclosed. The method includes the steps of growing a first layer on a substrate at a first temperature to obtain an incomplete crystalline structure including both indium and aluminum and having the composition expressed as In_XAl_YGa_1-X-YN(0≦X≦1, 0≦Y≦1). The method grows a cap layer on the first layer to cover the first layer, with growth of the cap layer proceeding at a second temperature substantially equal to or below the first temperature. The first layer is heat treated at a third temperature above the first temperature to cause the incomplete crystalline structure to crystallize and to create areas of differing compositions, thus changing the first layer to an active layer. The material of the cap layer is selected to be heat stable during the heat-treating step.

Claims

1. A nitride compound semiconductor with a mixed composition including areas where the composition is indium-rich and is expressed as In_X1Al_Y1Ga_1-X1-Y1N (0<

X1≦

1, 0≦

Y1≦

1) and other areas where it is aluminum-rich and is expressed as In_X2Al_Y2Ga_1-X2-Y2N (0<

X2<

X1≦

1, Y1<

Y2≦

1).

2. A nitride compound semiconductor light emitting device having a stack of layers including an active layer, a composition of each layer being expressed as In_XAl_YGa_1-X-YN (0≦

X≦

1, 0≦

Y≦

1) and the active layer comprising areas where the composition is indium-rich and expressed as In_X1Al_Y1Ga_1-X1-Y1N (0<

X1≦

1, 0≦

Y1≦

1) and comprising areas where the composition is aluminum-rich and expressed as In_X2Al_Y2Ga_1-X2-Y2N (0<

X2<

X1≦

1, Y1<

Y2≦

1).

3. A nitride compound semiconductor light emitting device having a stack of layers including an active layer, a composition of each layer being expressed as In_XAl_YGa_1-X-YN (0≦

X≦

1, 0≦

Y≦

1) and the active layer comprising areas where the composition is indium-rich and expressed as In_X1Al_1-X1N (0<

X1<

1) and comprising areas where the composition is aluminum-rich and expressed as In_X2Al_1-X2N (0<

X2<

X1<

1).

4. A method of manufacturing a nitride compound semiconductor having a stack of layers, the method including:

growing a first layer on a substrate at a first temperature to obtain an incomplete crystalline structure including both indium and aluminum having the composition expressed as In_XAl_YGa_1-X-YN (0<

X<

1, 0<

Y<

1),

growing a cap layer on the first layer to cover said first layer, the cap layer grown at a second temperature substantially equal to or below the first temperature; and

heat treating the first layer at a third temperature above the first temperature to at least partially crystallize the incomplete crystalline structure and to create areas within the first layer of differing compositions, thus changing the first layer to an active layer,

wherein the material of the cap layer is selected to be heat stable during the heat treating step.

5. The method of claim 4, wherein the heat treating produces a crystalline first layer.

6. The method of claim 4, wherein the heat treating produces a monocrystalline first layer.

7. The method of claim 4, wherein the material of the cap layer comprises a nitride compound semiconductor whose composition is expressed as In_XAl_YGa_1-X-YN (0≦

X≦

1, 0≦

Y≦

1).

8. A method of manufacturing a nitride compound semiconductor light emitting device having a stack of layers, the method including:

growing a first layer on a substrate at a first temperature to obtain an incomplete crystalline structure including both indium and aluminum and having a composition expressed as In_XAl_YGa_1-X-YN(0<

X≦

1, 0<

Y≦

1);

growing a cap layer on the first layer to cover the first layer, the growth proceeding at a second temperature substantially equal to or below the first temperature; and

heat treating the first layer at a third temperature above the first temperature to crystallize the incomplete crystalline structure and to create areas of differing compositions, thus changing the first layer to an active layer,

wherein the material of the cap layer is selected to be heat stable during the heat treating step.

10. The method of claim 8, wherein the material of the cap layer comprises a nitride compound semiconductor with its composition is expressed as In_XAl_YGa_1-X-YN (0≦

X≦

1, 0≦

Y≦

1).

9. A method of manufacturing a nitride compound semiconductor light emitting device having a stack of layers including a first cladding layer and a second cladding layer, the method including:

growing a first layer on the first cladding layer at a first temperature to obtain an incomplete crystalline structure including both indium and aluminum having a composition expressed as In_XAl_YGa_1-X-YN (0<

X≦

1, 0<

Y≦

1),

growing the second cladding layer on the first layer to cover the first layer at a second temperature substantially equal to or below the first temperature; and

heat treating the first layer at a third temperature above the first temperature to cause the incomplete crystalline structure to crystallize and to create areas of differing compositions, thus changing the first layer to an active layer,

wherein the material of the second cladding layer is selected to be heat stable during the heat treating step.

11. The method of claim 9, wherein the material of the second cladding layer comprises a nitride compound semiconductor with its composition expressed as In_XAl_YGa_1-X-YN (0≦

X≦

1, 0≦

Y≦

1).