Semiconductor device and process for producing the same
View Patent ↗There is provided a semiconductor device configured as follows. On a semiconductor substrate, a titanium oxide film which is an insulating film having a higher dielectric constant than that of a silicon dioxide film is formed as a gate insulating film, and a gate electrode is disposed thereon, resulting in a field effect transistor. The end portions in the gate length direction of the titanium oxide film are positioned inwardly from the respective end portions on the source side and on the drain side of the gate electrode, and the end portions of the titanium oxide film are positioned in a region in which the gate electrode overlaps with the source region and the drain region in plan configuration. This semiconductor device operates at a high speed, and is excellent in short channel characteristics and driving current. Further, in the semiconductor device, the amount of metallic elements introduced into a silicon substrate is small.
1. A semiconductor device having a semiconductor substrate and a field effect transistor formed on said semiconductor substrate, said field effect transistor comprising source and drain regions formed in said semiconductor substrate, a gate insulating film formed on said semiconductor substrate, and a gate electrode disposed on said gate insulating film,
said gate insulating film being a first insulating film having a higher dielectric constant than that of a silicon dioxide film, and having a laminated structure of a first layer comprising a compound of metal and oxygen, and a second layer comprising a compound of metal, oxygen and silicon,
said first layer being arranged between said gate electrode and said second layer, and
the end portions in the gate length direction of said first layer being positioned inwardly from the end portions of said gate electrode, the end portions in the gate length direction of said second layer being positioned inwardly from said end portions of said gate electrode and inwardly from said end portions of said first layer, and said end portions of said first layer and said end portions of said second layer being positioned in a region in which said gate electrode overlaps with said source and drain regions in a plan configuration.
2. The semiconductor device according to claim 1 ,
wherein an second insulating film having a lower dielectric constant than that of said gate insulating film is provided laterally of the end portions in the gate length direction of said gate insulating film, and between said gate electrode and said source and drain regions.
3. The semiconductor device according to claim 1 , wherein said end portions of said second layer are positioned inwardly from said end portions of said gate electrode by 15 nm to 25 nm, respectively.
4. The semiconductor device according to claim 1 , wherein said first layer is comprised of an oxide of at least one metal selected from the group consisting of titanium, tantalum, hafnium, zirconium, aluminum, lanthanum, and strontium, and said second layer is comprised of a silicate compound of at least one metal selected from said group.
5. The semiconductor device according to claim 1 , wherein said gate electrode is a metal selected from at least one selected from the group consisting of tungsten, titanium, and molybdenum, or a nitride thereof or a silicide thereof.