Semiconductor device and manufacturing method of the same
To enhance reliability and performance of a semiconductor device that has a fully-depleted SOI transistor, while a width of an offset spacer formed on side walls of a gate electrode is configured to be larger than or equal to a thickness of a semiconductor layer and smaller than or equal to a thickness of a sum total of a thickness of the semiconductor layer and a thickness of an insulation film, an impurity is ion-implanted into the semiconductor layer that is not covered by the gate electrode and the offset spacer. Thus, an extension layer formed by ion implantation of an impurity is kept from entering into a channel from a position lower than the end part of the gate electrode.
1. A manufacturing method of a semiconductor device to form a first field effect transistor in a first region, and form a second field effect transistor in a second region different from the first region, the method comprising the steps of:
(a) preparing an SOI substrate that has a semiconductor substrate, an insulation film on the semiconductor substrate and a semiconductor layer on the insulation film;
(b) removing the insulation film and the semiconductor layer in the second region;
(c) forming a first gate electrode via a first gate insulation film on the semiconductor layer in the first region, and forming a second gate electrode via a second gate insulation film on the semiconductor substrate in the second region;
(d) forming a first offset spacer on each side wall of the first gate electrode and the second gate electrode;
(e) forming a first extension layer of a first conductivity type on the semiconductor substrate in both sides of the second gate electrode by ion-implanting a first impurity into the semiconductor substrate that is not covered by the second gate electrode and the first offset spacer in the second region after the process (d);
(f) forming a first sidewall spacer of a first width on side walls of the first gate electrode in the first region via the first offset spacer after the process (e);
(g) forming an epitaxial layer on the semiconductor layer exposed without being covered by the first gate electrode, the first offset spacer and the first sidewall spacer in the first region after the process (f);
(h) removing the first sidewall spacer after the process (g);
(i) forming a second offset spacer of a second width smaller than the first width on each side wall of the first gate electrode and the second gate electrode via the first offset spacer after the process (h);
(j) forming a second extension layer of the first conductivity type in the semiconductor layer in both sides of the first gate electrode by ion-implanting a second impurity into the semiconductor layer that is not covered by the first gate electrode, the first offset spacer and the second offset spacer in the first region after the process (i) ;
(k) forming a second sidewall spacer on each side wall of the first gate electrode and the second gate electrode via the first offset spacer and the second offset spacer after the process (j); and
(l) forming a first diffusion region of the first conductivity type in a laminate section of the epitaxial layer and the semiconductor layer in the first region after the process (k),
wherein, in the process (i), a width of a sum total of the first offset spacer and the second offset spacer that cover side walls of the first gate electrode is larger than or equal to a thickness of the semiconductor layer and smaller than or equal to a thickness of a sum total of the semiconductor layer and the insulation film.
2. The manufacturing method of the semiconductor device according to claim 1 , further comprising the step of
(m) forming a silicide layer on the epitaxial layer after the process (l).
3. The manufacturing method of the semiconductor device according to claim 1 ,
wherein a thickness of the semiconductor layer is 10 to 20 nm, and a thickness of the insulation film is 10 to 20 nm.
4. The manufacturing method of the semiconductor device according to claim 1 ,
wherein a thickness of the first gate insulation film is smaller than a thickness of the second gate insulation film.
5. The manufacturing method of the semiconductor device according to claim 1 ,
wherein, in the process (l), at the same time of forming the first diffusion region in the first region, a second diffusion region of the first conductivity type is formed in the semiconductor substrate in both sides of the first gate electrode in the second region.
6. The manufacturing method of the semiconductor device according to claim 1 , further comprising the step of
(n) forming a semiconductor region of a second conductivity type that is different from the first conductivity type in a channel side of the first extension layer in the semiconductor substrate on both sides of the second gate electrode by ion-implanting a third impurity into the semiconductor substrate that is not covered by the second gate electrode and the first offset spacer in the second region before or after the process (e).