METHOD FOR MANUFACTURING SEMICONDUCTOR DEVICE AND SEMICONDUCTOR DEVICE
A method of manufacturing a semiconductor device is disclosed comprising providing an insulating carrier ( 10 ) such as an oxide wafer; providing a channel structure ( 20 ) between a source structure ( 12 ) and a drain structure ( 14 ) on said carrier ( 10 ); selectively removing a part of the channel structure ( 20 ), thereby forming a recess ( 22 ) between the channel structure ( 20 ) and the carrier ( 10 ); exposing the device to an annealing step such that the channel structure ( 20 ′) obtains a substantially cylindrical shape; forming a confinement layer ( 40 ) surrounding the substantially cylindrical channel structure ( 20 ′); growing an oxide layer ( 50 ) surrounding the confinement layer ( 40 ); and forming a gate structure ( 60 ) surrounding the oxide layer ( 50 ). The substantially cylindrical channel structure 20 ′ may comprise the semiconductor layer 30 . A corresponding semiconductor device is also disclosed.
1 . A method of manufacturing a semiconductor device, comprising:
providing an insulating carrier;
providing a channel structure between a source structure and a drain structure on said carrier;
selectively removing a part of the channel structure, thereby forming a recess between the channel structure and the carrier;
annealing the device such that the channel structure obtains a substantially cylindrical shape;
forming a confinement layer surrounding the substantially cylindrical channel structure;
growing an oxide layer surrounding the confinement layer; and
forming a gate structure surrounding the oxide layer.
2 . A method as claimed in claim 1 , further comprising growing a semiconducting layer surrounding the substantially cylindrical channel structure prior to forming the confinement layer, and wherein the confinement layer surrounds the substantially cylindrical channel structure and the semiconducting layer, the substantially cylindrical channel structure acting as a further confinement layer for the semiconducting layer.
3 . A method as claimed in claim 2 , wherein the semiconducting layer is grown epitaxially.
4 . A method as claimed in claim 1 , wherein the channel structure has a square cross section.
5 . A method as claimed in claim 1 , wherein the annealing step comprises a hydrogen annealing.
6 . A method as claimed in claim 1 , wherein the channel structure is a silicon channel structure, and wherein of forming a confinement layer comprises:
growing a silicon/germanium (SiGe) layer surrounding the substantially cylindrical channel structure; and
growing the oxide layer surrounding the SiGe layer at a predefined temperature, said predefined temperature facilitating the migration of Ge atoms from the SiGe layer towards the substantially cylindrical channel structure, thereby converting the SiGe layer into the confinement layer.
7 . A method as claimed in claim 1 , wherein the channel structure is a strained silicon channel structure, and wherein forming the confinement layer comprises epitaxially growing a SiGe layer.
8 . A method as claimed in claim 2 , wherein:
the channel structure is a silicon channel structure; and
growing a semiconducting layer further comprises epitaxially growing a SiGe layer; and
forming the confinement layer further comprises epitaxially growing a silicon layer surrounding the SiGe layer.
9 . A method as claimed in claim 2 , wherein:
the channel structure is a SiGe channel structure;
growing a semiconducting layer further comprises growing a strained silicon layer; and
forming the confinement layer further comprises epitaxially growing a SiGe layer surrounding the strained silicon layer.
10 . A semiconductor device on an insulating carrier, the device comprising a source region, a drain region, and a channel structure between the source region and the drain region, the channel structure comprising:
a substiantially cylindrical core structure comprising a semiconducting material;
a confinement layer surrounding the core structure;
an oxide layer surrounding the confinement layer; and
a gate structure surrounding the oxide layer.
11 . A semiconductor device as claimed in claim 10 , wherein the core structure comprises a further confinement structure surrounded by a layer of the semiconducting material.
12 . A semiconductor device as claimed in claim 10 , wherein the semiconducting material is silicon/germanium and the confinement structure(s) comprises silicon.
13 . A semiconductor device as claimed in claim 10 , wherein the semiconducting material is strained silicon and the confinement structure(s) comprises silicon/germanium.
14 . An integrated circuit comprising a plurality of semiconductor devices as claimed in claim 10 .