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US 5,179,034 AGranted
Method for fabricating insulated gate semiconductor device
AssigneeHitachi, Ltd.
InventorsMutsuhiro Mori, Tomoyuki Tanaka, Yasumichi Yasuda, Yasunori Nakano
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Abstract
A method for fabricating an insulated gate semiconductor device comprises the steps of forming insulated gates on an n.sup.- -layer surface, forming p-well layers in the n.sup.- -layer using the insulated gates as masks, forming phosphosilicate glass layers on the side walls of the insulated gates and diffusing the impurities from the phosphosilicate glass layers into the p-well layers to form n.sup.30 -source layer.
Claims9
A method for fabricating insulated gate semiconductor devices comprising the steps of:
- forming a plurality of insulated gates, each consisting of three layers of a gate oxide film, a gate electrode and an insulating film, at predetermined intervals on the surface of a semiconductor layer of a first conductivity type;
- after forming the plurality of insulated gates having the gate oxide film, the gate electrode and the insulating film, forming well layers of a second conductivity type opposite the first conductivity type in the semiconductor layer using the insulated gates as masks, said well layers each having a higher impurity concentration than that of the semiconductor layer;
- forming, on an insulator film located only on the side walls of each of the insulated gates in regions between the insulated gates, films doped with impurities of the first conductivity type in regions between the insulated gates;
- diffusing the impurities from the films doped with the first conductivity type impurities into the well layers to form source layers each having the first conductivity type and a higher concentration than that of the well layers;
- and
- forming a source electrode kept in ohmic contact with the exposed portions of the source layers and the well layers and extended over the insulated gates.
3 more elements
A method for fabricating an insulated gate semiconductor device comprising the steps of:
- forming a plurality of insulated gates, each consisting of three layers of a gate oxide film, a gate electrode and an insulating film, at predetermined intervals on the surface of a semiconductor layer of a first conductivity type, with the gate electrode between the gate oxide film and the insulating film;
- after forming the insulated gates having the gate oxide film, the gate electrode and the insulating film, forming a plurality of well layers of a second conductivity type opposite the first conductivity type in the semiconductor layer using the insulated gates as masks, said well layers each having a higher impurity concentration than that of the semiconductor layer;
- forming an insulating film on the entire surface of the insulated gates and the well layers;
- removing said insulating film by anisotropic-dry-etching so that a remaining portion thereof is left on only the side walls of the insulated gates in regions between the insulated gates;
- forming a doped film on the entire surface of the insulated gates and well layers;
- removing said doped film by anisotropic-dry-etching so that a remaining portion of the doped film is left on only the side walls of the insulated gates in regions between the insulated gates;
- diffusing the impurities from the remaining portion of the doped film on the side walls of the insulated gates into the well layers to form source layers each having the first conductivity type and a higher concentration than that of the well layers;
- and
- forming a source electrode in ohmic contact with exposed portions of the source layers and the well layers, and extending over the insulated gates.
6 more elements
A method for fabricating an insulated gate semiconductor device comprising the steps of:
- forming a plurality of insulated gates, each consisting of three layers of a gate oxide film, a gate electrode and an insulating film, at predetermined intervals on the surface of a semiconductor layer of a first conductivity type;
- after forming the insulated gates having the gate oxide film, the gate electrode and the insulating film, forming a plurality of well layers of a second conductivity type opposite the first conductivity type in the semiconductor layer using the insulated gates as masks, said well layers each having a higher impurity concentration than that of the semiconductor layer;
- forming an insulator film on the entire surface of the insulated gates and the well layers;
- removing said insulator film by anisotropic-dry-etching so that it is left on only the side walls of the insulated gates in regions between the insulated gates;
- forming a doped film on the entire surface of the insulated gates and the well layers;
- removing said doped film by anisotropic-dry-etching so that a remaining portion of the doped film is left on only the side walls of the insulated gates in regions between the insulated gates;
- diffusing the impurities from the remaining portion of the doped film, on the side walls of the insulated gates, into the well layers to form source layers each having the first conductivity type and a higher concentration than that of the well layers;
- and
- forming a source electrode kept in ohmic contact with the exposed portions of the source layers and the well layers and extended over the insulated gates.
6 more elements
Dependencies are inferred from the claim text.