Semiconductor device and method of manufacturing semiconductor device

A method of manufacturing a semiconductor device, wherein

• the semiconductor device includes
• a first semiconductor layer of a first conductivity type, and
• a second semiconductor layer of the first conductivity type having impurity concentration of the first conductivity type higher than that of the first semiconductor layer and having an adjacent portion being a portion adjacent to the first semiconductor layer, the portion being covered by the first semiconductor layer, wherein
• a portion of the second semiconductor layer exposed from the first semiconductor layer corresponds to a concave portion of a laminated structure of the first semiconductor layer and the second semiconductor layer,
• the first semiconductor layer or the first semiconductor layer and the adjacent portion of the second semiconductor layer corresponds to a convex portion of the laminated structure,
• a first guard ring of a second conductivity type is arranged on side walls of the convex portion, a lowest portion of the first guard ring being above a highest portion of a second guard ring,
• in the concave portion, the second guard ring of the second conductivity type is arranged in the concave portion and a thickness of the second guard ring is less than a thickness of the first guard ring, and
• in the method of manufacturing,
• the first guard ring is formed by ion implantation, and
• a tilt angle formed between a direction of the ion implantation and an out-of-plane direction of the first semiconductor layer is 30° or more in cross-sectional view.

A method of manufacturing a semiconductor device, wherein

• the semiconductor device includes
• a first semiconductor layer of a first conductivity type, and
• a second semiconductor layer of the first conductivity type having impurity concentration of the first conductivity type higher than that of the first semiconductor layer and having an adjacent portion being a portion adjacent to the first semiconductor layer, the portion being covered by the first semiconductor layer, wherein
• a portion of the second semiconductor layer exposed from the first semiconductor layer corresponds to a concave portion of a laminated structure of the first semiconductor layer and the second semiconductor layer,
• the first semiconductor layer or the first semiconductor layer and the adjacent portion of the second semiconductor layer corresponds to a convex portion of the laminated structure,
• a first guard ring of a second conductivity type is arranged on side walls of the convex portion, a lowest portion of the first guard ring being above a highest portion of a second guard ring,
• in the concave portion, the second guard ring of the second conductivity type is arranged in the concave portion and a thickness of the second guard ring is less than a thickness of the first guard ring, and
• in the method of manufacturing,
• the first guard ring is formed by ion implantation, and
• a rotation angle formed between a direction of the ion implantation and a longitudinal direction of the convex portion is −35° or more and 35° or less in plan view.