GALLIUM NITRIDE BASED COMPOUND SEMICONDUCTOR LIGHT-EMITTING ELEMENT AND METHOD FOR FABRICATING THE SAME

1 . A gallium nitride based compound semiconductor light-emitting element comprising:

an n-type gallium nitride based compound semiconductor layer;

a p-type gallium nitride based compound semiconductor layer;

an active layer which is arranged between the n- and p-type gallium nitride based compound semiconductor layers; and

a p-type Al x Ga y N (where 0<x≦1 and 0≦y<1) electron blocking layer which is arranged between the p-type gallium nitride based compound semiconductor layer and the active layer, wherein

the active layer and the p-type gallium nitride based compound semiconductor layer are m-plane semiconductor layers;

the p-type gallium nitride based compound semiconductor layer includes magnesium at a concentration of 2.0×10 18 cm −3 to 2.5×10 19 cm −3 and oxygen, of which the concentration is 5% to 15% of the concentration of the magnesium;

the p-type Al x Ga y N (where 0<x≦1 and 0≦y<1) electron blocking layer is adjacent to the p-type gallium nitride based compound semiconductor layer; and

the p-type Al x Ga y N (where 0<x≦1 and 0≦y<1) electron blocking layer has a higher oxygen concentration than the p-type gallium nitride based compound semiconductor layer.

2 . The gallium nitride based compound semiconductor light-emitting element of claim 1 , wherein the p-type gallium nitride based compound semiconductor layer further includes hydrogen at a concentration of 2.0×10 17 cm −3 to 2.5×10 18 cm −3 .

3 . The gallium nitride based compound semiconductor light-emitting element of claim 2 , wherein in the p-type gallium nitride based compound semiconductor layer, the concentration of the oxygen included is 60% to 200% of the concentration of the hydrogen included.

4 . The gallium nitride based compound semiconductor light-emitting element of claim 1 , further comprising an undoped spacer layer which is arranged between the active layer and the p-type gallium nitride based compound semiconductor layer and which has a thickness of 100 nm or less.

5 . The gallium nitride based compound semiconductor light-emitting element of claim 1 , wherein the active layer has a multiple quantum well structure.

6 . The gallium nitride based compound semiconductor light-emitting element of claim 1 , wherein the concentration of hydrogen included in the n-type gallium nitride based compound semiconductor layer and the active layer is less than 2.0×10 17 cm −3 .

7 . The gallium nitride based compound semiconductor light-emitting element of claim 6 , wherein the concentration of hydrogen included in the n-type gallium nitride based compound semiconductor layer is equal to or lower than the concentration of hydrogen included in the active layer.

8 . The gallium nitride based compound semiconductor light-emitting element of claim 1 , wherein the p-type gallium nitride based compound semiconductor layer has a thickness of 50 nm to 500 nm.

9 . The gallium nitride based compound semiconductor light-emitting element of claim 1 , further comprising a p-type contact layer which contacts with both an electrode and the p-type gallium nitride based compound semiconductor layer,

wherein the p-type contact layer includes magnesium at a concentration of at least 4.0×10 19 cm −3 and has a thickness of 20 nm to 100 nm.

10 . The gallium nitride based compound semiconductor light-emitting element of claim 1 , wherein the p-type gallium nitride based compound semiconductor layer is made of GaN.

11 . A light source comprising:

the gallium nitride based compound semiconductor light-emitting element of claim 1 ; and

a wavelength changing section which includes a phosphor that changes the wavelength of light emitted from the gallium nitride based compound semiconductor light-emitting element.

12 . A method for fabricating a gallium nitride based compound semiconductor light-emitting element, the method comprising the steps of:

forming an n-type gallium nitride based compound semiconductor layer;

forming a p-type gallium nitride based compound semiconductor layer as an m-plane semiconductor layer; and

forming an active layer as another m-plane semiconductor layer between the n- and p-type gallium nitride based compound semiconductor layers,

wherein the step of forming the p-type gallium nitride based compound semiconductor layer includes forming the p-type gallium nitride based compound semiconductor layer by adjusting the flow rate of a magnesium source gas so that the p-type gallium nitride based compound semiconductor layer includes magnesium at a concentration of 2.0×10 18 cm −3 to 2.5×10 19 cm −3 and oxygen, of which the concentration is 5% to 15% of the concentration of the magnesium.

13 . The method of claim 12 , wherein the step of forming the p-type gallium nitride based compound semiconductor layer includes controlling the concentrations of oxygen and magnesium in the p-type gallium nitride based compound semiconductor layer by adjusting respective flow rates of both the magnesium source gas and a gallium source gas.

14 . The method of claim 12 , wherein the step of forming the p-type gallium nitride based compound semiconductor layer includes setting the flow rate of the gallium source gas to fall within the range of 15 μmol/min to 110 μmol/min.

15 . The method of claim 12 , wherein the step of forming the p-type gallium nitride based compound semiconductor layer includes setting the growth rate of the p-type gallium nitride based compound semiconductor layer to fall within the range of 4 nm/min to 28 nm/min.