CMOS semiconductor device having boron doped channel
AssigneeSemiconductor Energy Laboratory Co., Ltd.
InventorsShunpei Yamazaki, Hisashi Ohtani, Takeshi Fukunaga
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Abstract
A semiconductor device having a CMOS structure, wherein, in manufacturing a CMOS circuit, an impurity element which imparts p-type conductivity to the active layer of the p-channel type semiconductor device is added before forming the gate insulating film. Then, by applying thermal oxidation treatment to the active layer, the impurity element is subjected to redistribution, and the concentration of the impurity element in the principal surface of the active layer is minimized. The precise control of threshold voltage is enabled by the impurity element that is present in a trace quantity.
Claims12
A semiconductor device having a CMOS structure, said semiconductor device comprising:
- an n-channel semiconductor device;
- a p-channel semiconductor device which is complementarily combined with said n-channel semiconductor to form said CMOS structure, said p-channel semiconductor device having an active layer including a channel region;
- and
- a substrate having an insulating surface on which said n-channel semiconductor device and said p-channel semiconductor device are formed;
- wherein at least the channel region of the active layer of only said p-channel semiconductor device is doped with a p-type impurity element;
- wherein the distribution of concentration of said p-type impurity element depth wise tends to decrease in the inside of the active layer approaching the interface between said channel region and a thermal oxide film formed on said active layer;
- and
- wherein said p-type impurity element in said interface is used to control a threshold voltage.
A semiconductor device having a CMOS structure, said semiconductor device comprising:
- an n-channel semiconductor device having an active layer including a channel region;
- a p-channel semiconductor device which is complementarily combined with said n-channel semiconductor device to form said CMOS structure, said p-channel semiconductor device having an active layer including a channel region;
- and
- a substrate having an insulating surface on which said n-channel semiconductor device and said p-channel semiconductor device are formed;
- wherein at least the channel region of the active layer of said p-channel semiconductor device is doped with a p-type impurity element;
- wherein at least an edge portion of the active layer of said n-channel semiconductor device is doped with a p-type impurity element;
- wherein the distribution of concentration of said impurity element depthwise is continuously reduced toward a main surface of said active layer in the vicinity of the main surface of said active layer;
- and
- wherein said impurity element in the vicinity of the main surface of said active layer is intended use to control a threshold voltage.
Dependencies are inferred from the claim text.