Method for producing pillar-shaped semiconductor device

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

• a step of forming a first semiconductor pillar that extends in a direction vertical to the substrate;
• a step of forming a first gate insulating layer that surrounds a periphery of the first semiconductor pillar;
• a step of forming a first gate conductor layer that surrounds the first gate insulating layer;
• a step of forming a first impurity region that is in contact with an inside or a side surface of the first semiconductor pillar, the first impurity region having an upper end positioned at a lower end of the first gate insulating layer in the vertical direction;
• a step of forming a first insulating layer having an upper surface positioned higher than an upper end of the first gate conductor layer and lower than a top of the first semiconductor pillar in the vertical direction;
• a step of forming a first material layer that surrounds a side surface of an upper portion of the first semiconductor pillar, the upper portion being exposed at a position higher than an upper surface of the first insulating layer;
• a step of forming a recess by etching a top portion of the first semiconductor pillar using the first material layer as a mask;
• a step of forming, in the recess, a second impurity region containing a donor or acceptor impurity by epitaxial crystal growth;
• a step of removing the first material layer;
• a step of forming a second material layer that surrounds a side surface of the second impurity region positioned higher than the first insulating layer;
• a step of forming a third material layer on a periphery of the second material layer;
• a step of forming a first contact hole having a bottom on the first insulating layer by etching the second material layer using the third material layer and the second impurity region as etching masks;
• and
• a step of filling the first contact hole with a first conductor material layer having electrical conductivity and having a single-layer structure or a multilayer structure.