Method for producing pillar-shaped semiconductor device

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

• forming a semiconductor pillar so as to stand vertically from a substrate;
• forming a gate insulating layer around a side surface of the semiconductor pillar;
• forming a gate conductor layer around a side surface of the gate insulating layer;
• forming a first impurity region below the gate insulating layer in contact with a lower portion or the side surface of the semiconductor pillar, wherein the first impurity region contains a donor or acceptor impurity;
• and
• forming a second impurity region above the gate insulating layer on a top portion of the semiconductor pillar, wherein the second impurity region contains a donor or acceptor impurity,
• wherein the step of forming the first impurity region comprises:
• forming a first material layer around a bottom portion of the semiconductor pillar;
• forming a second material layer on the first material layer around the semiconductor pillar with a constant horizontal width, wherein the second material layer is constituted by a single layer or a plurality of vertically formed layers;
• vertically etching the first material layer, using the second material layer as a mask, to form an opening portion through which a side surface of a lower portion of the semiconductor pillar is exposed;
• and
• forming the first impurity region by a selective epitaxial crystal growth method so that the first impurity region horizontally extends from the side surface of the semiconductor pillar out of the opening portion.

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

• forming a semiconductor pillar so as to stand vertically from a substrate;
• forming a gate insulating layer so as to surround a side surface of the semiconductor pillar;
• forming a gate conductor layer so as to surround a side surface of the gate insulating layer;
• forming a first impurity region below the gate insulating layer in contact with a lower portion or the side surface of the semiconductor pillar, wherein the first impurity region contains a donor or acceptor impurity;
• and
• forming a second impurity region above the gate insulating layer on a top portion of the semiconductor pillar, wherein the second impurity region contains a donor or acceptor impurity,
• wherein the step of forming the semiconductor pillar comprises etching a semiconductor layer formed on the substrate using, as a mask, a mask material layer formed on the semiconductor layer,
• the step of forming the first impurity region comprises forming a third material layer around the side surface of the semiconductor pillar, and
• the step of forming the second impurity region comprises forming a first material layer around the top portion of the semiconductor pillar and etching the top portion of the semiconductor pillar using the first material layer as a mask to form a recessed portion above the etched semiconductor pillar;
• and
• the method further comprising:
• forming a second material layer around the side surface of the semiconductor pillar below the gate insulating layer;
• etching the second material layer to form an opening portion around the side surface of the semiconductor pillar below the gate insulating layer;
• simultaneously forming the second impurity region in the recessed portion and the first impurity region in the opening portion, using a selective epitaxial crystal growth method;
• and
• performing oxidation, using the mask material layer and the third material layer as anti-oxidation masks, to form an oxidized layer in an upper portion of the semiconductor layer around a bottom portion of the semiconductor pillar.

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

• forming a semiconductor pillar so as to stand vertically from a substrate;
• forming a gate insulating layer around a side surface of the semiconductor pillar;
• forming a gate conductor layer around a side surface of the gate insulating layer;
• forming a first impurity region below the gate insulating layer in contact with a lower portion or the side surface of the semiconductor pillar, wherein the first impurity region contains a donor or acceptor impurity;
• and
• forming a second impurity region above the gate insulating layer on a top portion of the semiconductor pillar, wherein the second impurity region contains a donor or acceptor impurity,
• wherein the step of forming the first impurity region comprises:
• forming a first material layer around a bottom portion of the semiconductor pillar;
• forming a second material layer on the first material layer around the semiconductor pillar with a constant horizontal width, wherein the second material layer is constituted by a single layer or a plurality of vertically formed layers;
• vertically etching the first material layer, using the second material layer as a mask, to form an opening portion through which a side surface of a lower portion of the semiconductor pillar is exposed;
• and
• forming the first impurity region by a selective epitaxial crystal growth method so that the first impurity region horizontally extends from the side surface of the semiconductor pillar out of the opening portion,
• wherein the step of forming the semiconductor pillar comprises etching a semiconductor layer formed on the substrate using, as a mask, a mask material layer formed on the semiconductor layer,
• the step of forming the first impurity region comprises forming a third material layer around the side surface of the semiconductor pillar, and
• the method further comprising performing oxidation, using the mask material layer and the third material layer as anti-oxidation masks, to form an oxidized layer in an upper portion of the semiconductor layer around a bottom portion of the semiconductor pillar.