Semiconductor device and method of fabricating the same
View Patent ↗A semiconductor device according to an embodiment of the present invention includes: a square pole-shaped channel portion made from a first semiconductor layer formed on a substrate, and surrounded with four side faces; a gate electrode formed on a first side face of the channel portion, and a second side face of the channel portion opposite to the first side face through respective gate insulating films; a source region having a conductivity type different from that of the channel portion and being formed on a third side face of the channel portion, the source region including a second semiconductor layer having a lattice constant different from that of the first semiconductor layer and being formed directly on the substrate; and a drain region having a conductivity type different from that of the channel portion and being formed on a fourth side face of the channel portion opposite to the third side face, the drain region including the second semiconductor layer being formed directly on the substrate.
1. A method of fabricating a semiconductor device, comprising:
processing a semiconductor layer laminated on a substrate, thereby forming a fin-shaped first semiconductor layer,
forming a gate electrode on parts of both side faces of the first semiconductor layer through respective gate insulating films;
forming sidewall films on regions, each having no gate electrode formed thereon, of the both side faces of the first semiconductor layer;
removing the first semiconductor layer until a surface of the substrate is exposed while a part of the first semiconductor layer is left between the sidewall films; and
growing a second semiconductor layer from a surface of the part of the first semiconductor layer thus left to fill a gap defined between the sidewall films with the second semiconductor layer, thereby forming a source region and a drain region each having a conductivity type different from that of the first semiconductor layer.
2. A method of fabricating a semiconductor device according to claim 1 , wherein the first semiconductor layer is removed so that a portion of the first semiconductor layer located in a region in a vicinity of a center between the sidewall films is left in plate shape.
3. A method of fabricating a semiconductor device according to claim 2 , wherein the first semiconductor layer is removed in an etching process using an etching mask.
4. A method of fabricating a semiconductor device according to claim 1 , wherein the first semiconductor layer is removed so that a portion of the first semiconductor layer located in a region in a vicinity of the surface of the substrate in a region in a vicinity of a center between the sidewall films is left in rod shape.
5. A method of fabricating a semiconductor device according to claim 4 , wherein the first semiconductor layer is removed in an anisotropic etching process.
6. A method of fabricating a semiconductor device according to claim 1 , wherein the first semiconductor layer is removed so that a portion of the first semiconductor layer located in a region in a vicinity of the surface of the substrate is left in a form of a plurality of protrusions.
7. A method of fabricating a semiconductor device according to claim 6 , wherein the first semiconductor layer is removed such that an upper portion of the first semiconductor layer is removed in a first anisotropic etching process, and a lower portion of the first semiconductor layer is removed in a second anisotropic etching process performed under a condition that an etching deposit is more in the second anisotropic etching process than in the first anisotropic etching process.