Nitride semiconductor light emitting device and method for forming the same

A method for forming a nitride semiconductor light emitting device comprising:

• a step of preparing a substrate composed of a hexagonal AlZGa1-ZN semiconductor (0≦Z≦1);
• a step of forming a first conduction type gallium nitride-based semiconductor film on a primary surface of the substrate;
• a step of forming an active layer which emits light having a wavelength in the range of 440 to 550 nm on the first conductive type gallium nitride-based semiconductor film;
• and
• a step of forming a second conduction type gallium nitride-based semiconductor film on the active layer,
• wherein the first conduction type gallium nitride-based semiconductor film, the active layer, and the second conduction type gallium nitride-based semiconductor film are disposed on the primary surface of the substrate in a predetermined axis direction,
• in the step of forming the active layer, a first semiconductor layer composed of hexagonal InXGa1-XN (0.16≦X≦0.35, X:
• strained composition) and having a first gallium composition is grown at a first temperature,
• in the step of forming the active layer, a second semiconductor layer composed of hexagonal InYGa1-YN (0≦Y≦0.05, Y<X, Y:
• strained composition) and having a second gallium composition is grown at a second temperature,
• the first gallium composition is lower than the second gallium composition,
• the first temperature is lower than the second temperature,
• the difference between the first temperature and the second temperature is 105° C. or more, and
• the a-plane of the hexagonal InXGa1-XN is aligned in the predetermined axis direction.