Method for producing pillar-shaped semiconductor device

A method for producing a pillar-shaped semiconductor device, the method comprising:

• a step of providing a structure including:
• a substrate,
• a first semiconductor pillar that stands on a plane of the substrate in a vertical direction, and
• a first impurity region that is in contact with a lower portion of the first semiconductor pillar or a side surface of the lower portion and contains a donor or acceptor impurity atom;
• a step of forming a first material layer that has conductivity, extends in a horizontal direction, and is connected to, in plan view, at least one of an entire periphery of the lower portion of the first semiconductor pillar and an entire periphery of a first conductor layer surrounding a first insulating layer surrounding the first semiconductor pillar;
• a step of forming, on the first material layer, a second material layer that surrounds the first semiconductor pillar in plan view;
• a step of forming, on the first material layer, a third material layer that is partly connected to the second material layer in plan view;
• and
• a step of etching the first material layer using the second material layer and the third material layer as masks,
• wherein a first region of the first material layer that surrounds the first semiconductor pillar in plan view is formed below the second material layer, and a second region of the first material layer that is partly connected to the first region in plan view is formed below the third material layer.