Semiconductor device

A semiconductor device comprising:

• one or more LDMOS transistors;
• and
• a semiconductor substrate having an upper surface,
• wherein each of the one or more LDMOS transistors includes:
• a plurality of impurity diffusion layers formed in the semiconductor substrate at the upper surface;
• a plurality of drain layers formed in the semiconductor substrate at the upper surface;
• and
• a plurality of insulating films formed on the upper surface,
• wherein each of the plurality of impurity diffusion layers, each of the plurality of drain layers, and each of the plurality of insulating films extend along a first direction in plan view,
• wherein the plurality of impurity diffusion layers are arranged along a second direction perpendicular to the first direction in plan view while interposing a gap between two adjacent impurity diffusion layers among the plurality of impurity diffusion layers,
• wherein the plurality of impurity diffusion layers include a first impurity diffusion layer and a second impurity diffusion layer which are positioned on both ends in the second direction, and a third impurity diffusion layer positioned between the first impurity diffusion layer and the second impurity diffusion layer,
• wherein each of the plurality of drain layers is positioned between two adjacent impurity diffusion layers among the plurality of impurity diffusion layers,
• wherein each of the plurality of insulating films is positioned between one of the plurality of drain layers and one of the plurality of impurity diffusion layers which are adjacent to each other, to be in contact with one of the plurality of drain layers and to separate from one of the plurality of impurity diffusion layers,
• wherein each of the first impurity diffusion layer and the second impurity diffusion layer in a first LDMOS transistor among the one or more LDMOS transistors includes a first backgate layer but does not include a source layer, and
• wherein the third impurity diffusion layer in the first LDMOS transistor includes a second backgate layer and a first source layer which are alternately arranged along the first direction.