Method for fabricating semiconductor device using a CVD insulator film

Claim 1

A method for fabricating a semiconductor device functioning as an MOS field effect transistor, the method comprising the steps of: a) forming a gate insulator film and a gate electrode on a semiconductor substrate in this order; b) forming a CVD insulator film to cover an exposed surface of the gate electrode by performing a CVD process; c) etching anisotropically the CVD insulator, film to form sidewalls made from the CVD insulator film on the side faces of the gate electrode after the step b) has been performed; d) forming impurity layers of a first conductivity type in the semiconductor substrate by implanting dopant ions into the semiconductor substrate from above the gate electrode and the sidewalls made from the CVD insulator film; e) forming a diffusion layer composed of a punch through stopper of a second conductivity type in the semiconductor substrate by implanting dopant ions into the semiconductor substrate before or after the step d) has been performed; f) forming sidewall spacers over the side faces of the gate electrode with sidewalls made from the CVD insulator film interposed therebetween, after the steps d and e) have been performed; and g) forming source/drain layers of the first conductivity type in the semiconductor substrate, after the step f) has been performed; wherein the impurity layers of the first conductivity type over-lapped the gate electrode.

Claim 2

A method for fabricating a semiconductor device functioning as an MOS field effect transistor, the method comprising the steps of: a) forming a gate insulator film and a gate electrode on a semiconductor substrate in this order; b) forming a CVD insulator film to cover an exposed surface of the gate electrode by performing a CVD process; c) etching anisotropically the CVD insulator, film to form sidewalls made from the CVD insulator film on the side faces of the gate electrode after the step b) has been performed; d) forming impurity layers of a first conductivity type in the semiconductor substrate by implanting dopant ions into the semiconductor substrate from above the gate electrode and the sidewalls made from the CVD insulator film; e) forming a diffusion layer composed of a punch through stopper of a second conductivity type in the semiconductor substrate by implanting dopant ions into the semiconductor substrate before or after the step d) has been performed; f) forming sidewall spacers over the side faces of the gate electrode with sidewalls made from the CVD insulator film interposed therebetween, after the steps d and e) have been performed; and g) forming source/drain layers of the first conductivity type in the semiconductor substrate, after the step f) has been performed; wherein the impurity layers of the first conductivity type over-lapped the gate electrode.

Claim 6

A method for fabricating a semiconductor device functioning as an MOS field effect transistor, the method comprising the steps of: a) forming a gate insulator film and a gate electrode on a semiconductor substrate in this order; b) forming a CVD insulator film over the entire surface of the semiconductor substrate after the step a) has been performed; c) forming impurity layers of a first conductivity type in the semiconductor substrate by implanting dopant ions into the semiconductor substrate from above the CVD insulator film that is formed over the entire surface and covering an exposed surface of the gate electrode; d) conducting a heat treatment within an oxidizing and nitriding ambient or a nitriding ambient to repair damage caused in the gate insulator film due to the implantation of the dopant ions after the step c) has been performed and where the CVD insulator film is formed over the entire surface of the semiconductor substrate; e) forming sidewall spacers over the side faces of the gate electrode with the CVD insulator film interposed therebetween after the step d) has been performed; and f) forming source/drain layers of the first conductivity type in the semiconductor substrate after the step e) has been performed; wherein the impurity layers of the first conductivity type over-lapped the gate electrode.

Claim 7

A method for fabricating a semiconductor device functioning as an MOS field effect transistor, the method comprising the steps of: a) forming a gate insulator film and a gate electrode on a semiconductor substrate in this order; b) forming a CVD insulator film over the entire surface of the semiconductor substrate after the step a) has been performed; c) forming impurity layers of a first conductivity type in the semiconductor substrate by implanting dopant ions into the semiconductor substrate from above the CVD insulator film that is formed over the entire surface and covering an exposed surface of the gate electrode; d) conducting a heat treatment within an oxidizing and nitriding ambient or a nitriding ambient to repair damage caused in the gate insulator film due to the implantation of the dopant ions after the step c) has been performed and where the CVD insulator film is formed over the entire surface of the semiconductor substrate; e) forming sidewall spacers over the side faces of the gate electrode with the CVD insulator film interposed therebetween after the step d) has been performed; and f) forming source/drain layers of the first conductivity type in the semiconductor substrate after the step e) has been performed; wherein the impurity layers of the first conductivity type over-lapped the gate electrode.