Semiconductor devices having buried metal silicide layers and methods of fabricating the same

A semiconductor device comprising:

• a plurality of active pillars disposed on a substrate and spaced apart from each other by first trenches and second trenches which are alternately arrayed, each of the active pillars including an active region stacked on a buried metal silicide pattern;
• a full filling insulation layer which fills the first trenches;
• a partial filling insulation layer in the second trenches, the partial filling insulation layer being disposed between a bottom surface level of the second trenches and a first height level located at the same level as bottom surfaces of the buried metal silicide patterns;
• and
• spacers disposed on sidewalls of the active regions in the second trenches,
• wherein the active region includes impurity junction regions therein.

A semiconductor device comprising:

• a plurality of active pillars disposed on a substrate and spaced apart from each other by trenches, each of the active pillars including an active region stacked on a buried metal silicide pattern;
• a partial filling insulation layer in the trenches, the partial filling insulation layer being disposed between a bottom surface level of the trenches and a predetermined height level above the bottom surface level;
• and
• insulation patterns disposed in the trenches and configured to provide air gaps between sidewalls of the buried metal silicide patterns,
• wherein the sidewalls of the metal silicide patterns are exposed to the air gaps and each of the active regions includes impurity junction regions therein.

A semiconductor device comprising:

• a plurality of active pillars disposed on a substrate and spaced apart from each other by first trenches and second trenches which are alternately arrayed, each of the active pillars including an active region stacked on a buried metal silicide pattern;
• a full filling insulation layer which fills the first trenches;
• a partial filling insulation layer in the second trenches, the partial filling insulation layer being disposed between a bottom surface level of the second trenches and a first height level located at the same level as bottom surfaces of the buried metal silicide patterns;
• and
• insulation patterns disposed in the second trenches and configured to provide air gaps between sidewalls of the buried metal silicide patterns in the second trenches,
• wherein the active region includes impurity junction regions therein.

A method of fabricating a semiconductor device, the method comprising:

• forming trenches in a substrate to define a plurality of active pillars spaced apart from each other by the trenches;
• forming a partial filling insulation layer which fills lower regions in the trenches;
• forming a first sacrificial layer in the trenches on the partial filling insulation layer;
• forming spacers on sidewalls of the active pillars exposed by the trenches on the first sacrificial layer;
• removing the first sacrificial layer to expose sidewalls of the active pillars between a top surface of the partial filling insulation layer and bottom surfaces of the spacers;
• forming a metal layer contacting the exposed sidewalls of the active pillars;
• applying a silicidation process to the substrate including the metal layer to form metal silicide patterns in the active pillars;
• and
• removing the metal layer remaining in the trenches.

A method of fabricating a semiconductor device, the method comprising:

• forming first trenches and second trenches in a substrate to define a plurality of active pillars spaced apart from each other by the first and second trenches, the first trenches and the second trenches being alternately arrayed;
• forming a full filling insulation layer which fills the first and second trenches;
• selectively recessing the full filling insulation layer in the second trenches to form a partial filling insulation layer;
• forming a first sacrificial layer in the second trenches on the partial filling insulation layer;
• forming spacers on sidewalls of the active pillars exposed by the second trenches above the first sacrificial layer;
• removing the first sacrificial layer to expose sidewalls of the active pillars between a top surface of the partial filling insulation layer in the second trenches and bottom surfaces of the spacers in the second trenches;
• forming a metal layer contacting the exposed sidewalls of the active pillars;
• applying a silicidation process to the substrate including the metal layer to form metal silicide patterns in the active pillars;
• and
• removing the metal layer remaining after the silicidation process.