Semiconductor device
A semiconductor device includes a semiconductor substrate formed of at least two kinds of group III elements and nitrogen, an active layer formed on the semiconductor substrate, and a nitride semiconductor layer formed on a surface of the semiconductor substrate and formed between the semiconductor substrate and the active layer. The nitride semiconductor layer is formed of the same constituent elements of the semiconductor substrate. A composition ratio of the lightest element among the group III elements of the nitride semiconductor layer is higher than a composition ratio of the corresponding element of the semiconductor substrate.
1. A semiconductor device, comprising:
a semiconductor substrate formed of at least Ga and nitrogen;
an active layer formed on the semiconductor substrate; and
a nitride semiconductor layer formed on a surface of the semiconductor substrate between the semiconductor substrate and the active layer;
wherein a composition ratio of Ga in the nitride semiconductor layer is higher than a composition ratio of Ga in the semiconductor substrate, and
wherein the semiconductor substrate is a single layer.
2. The semiconductor device according to claim 1 , wherein the semiconductor substrate is InGaN.
3. The semiconductor device according to claim 1 , wherein the active layer is InGaN.
4. The semiconductor device according to claim 1 , wherein the nitride semiconductor layer is InGaN.
5. The semiconductor device according to claim 1 , further comprising a cladding layer formed of the same constituent element as a constituent element of the semiconductor substrate.
6. The semiconductor device according to claim 1 , wherein the nitride semiconductor layer is formed to contact with the surface of the semiconductor substrate.
7. The semiconductor device according to claim 1 , wherein the nitride semiconductor layer is formed as an altered layer where the surface of the semiconductor substrate is altered.