A manufacturing method of a semiconductor device comprises a step of ion-implanting a P-type impurity at a first dose amount to form semiconductor regions that are low concentration semiconductor regions of a high breakdown voltage P-type transistor, and a step of ion-implanting a P-type impurity at a second dose amount to form P.sup. semiconductor regions that are low concentration semiconductor regions of a low breakdown voltage P-type transistor and form a P-type impurity layer that is a resistance portion of a polysilicon resistor. The manufacturing method further comprises a resistance portion forming step in which a resistance portion of the polysilicon resistor is made thinner than terminal portions at both ends of the resistance portion, and the second dose amount is larger than the first dose amount.

A gate insulating film and a gate electrode of non-single crystalline silicon for forming an nMOS transistor are provided on a silicon substrate. Using the gate electrode as a mask, n-type dopants having a relatively large mass number (70 or more) such as As ions or Sb ions are implanted, to form a source/drain region of the nMOS transistor, whereby the gate electrode is amorphized. Subsequently, a silicon oxide film is provided to cover the gate electrode, at a temperature which is less than the one at which recrystallization of the gate electrode occurs. Thereafter, thermal processing is performed at a temperature of about 1000 C., whereby high compressive residual stress is exerted on the gate electrode, and high tensile stress is applied to a channel region under the gate electrode. As a result, carrier mobility of the nMOS transistor is enhanced.

A semiconductor device with improved roll-off resistivity and reliability are provided. The semiconductor device includes a gate dielectric overlying a semiconductor substrate, a gate electrode overlying the gate dielectric, a gate silicide region on the gate electrode, a source/drain region adjacent the gate dielectric, and a source/drain silicide region on the source/drain region, wherein the source/drain silicide region and the gate silicide region have different metal compositions.

Methods for forming a semiconductor structure and semiconductor structures are described. The method comprises patterning a substrate to form a first opening and a second opening, the substrate comprising an n transistor and a p transistor, the first opening over the n transistor and the second opening over the p transistor. The substrate may be pre-cleaned. A ruthenium silicide (RuSi) layer is selectively deposited on the p transistor. A titanium silicide (TiSi) layer is formed on the n transistor and the p transistor. An optional barrier layer may be formed on the titanium silicide (TiSi) layer. The method may be performed in a processing chamber without breaking vacuum.