A nitrogen-containing semiconductor device including a first type doped semiconductor layer, a multiple quantum well layer and a second type doped semiconductor layer is provided. The multiple quantum well layer includes barrier layers and well layers, and the well layers and the barrier layers are arranged alternately. The multiple quantum well layer is located between the first type doped semiconductor layer and the second type doped semiconductor layer, and one of the well layers of the multiple quantum well layer is connected to the second type doped semiconductor layer.