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US 2017/0256582 A1Published application
Semiconductor device and a method of manufacturing a semiconductor device
AssigneeSii Semiconductor Corporation
InventorToshiro FUTATSUGI
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Abstract
In order to form a light receiving element having high reliability and a MOS transistor together on the same silicon substrate, after forming a gate electrode of the MOS transistor, a gate oxide film in a light receiving element forming region is removed. Then, a thermal oxide film is newly formed in the light receiving element forming region, and ion implantation is performed in the light receiving element forming region through the thermal oxide film such that a shallow pn junction is formed.
Claims9
A method of manufacturing a semiconductor device, comprising:
- forming a first thermal oxide film serving as a gate oxide film of a MOS transistor on a surface of a silicon substrate having a light receiving element forming region and a MOS transistor forming region;
- forming a polysilicon film on the first thermal oxide film;
- patterning the polysilicon film, to thereby form a gate electrode of the MOS transistor in the MOS transistor forming region;
- removing the first thermal oxide film other than the first thermal oxide film under the gate electrode;
- forming a second thermal oxide film on the surface of the silicon substrate;
- and
- performing ion implantation of an impurity on the light receiving element forming region through the second thermal oxide film, to thereby form an impurity region.
4 more elements
A semiconductor device, comprising:
- a MOS transistor and a light receiving element formed on a silicon substrate,
- the MOS transistor comprising:
- a gate electrode;
- a first thermal oxide film for a gate oxide formed only under the gate electrode;
- a second thermal oxide film covering a side surface of the gate electrode and a side surface of the gate oxide film, and formed on a surface of the silicon substrate;
- a side wall formed on the second thermal oxide film, the side wall and the side surface of the gate electrode sandwiching the second thermal oxide film therebetween, and the side wall and the silicon substrate sandwiching the second thermal oxide film therebetween;
- and
- an LDD region formed on the silicon substrate, being self-alignment to the second thermal oxide film formed on the side surface of the gate electrode;
- the light receiving element comprising:
- the second thermal oxide film formed directly on the surface of the silicon substrate;
- an impurity region formed on the surface of the silicon substrate just under the second thermal oxide film;
- and
- an insulating film formed on the second thermal oxide film, the insulating film being a same film as that forms the side wall.
10 more elements
Dependencies are inferred from the claim text.