Semiconductor device of reduced gate overlap capacitance and method of manufacturing the semiconductor device
First Claim
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1. A semiconductor device including an MOS transistor comprising:
- a semiconductor substrate;
a gate insulating film selectively disposed on said semiconductor substrate;
a gate electrode selectively disposed on said gate insulating film; and
a spacer insulating film disposed on a side surface of said gate electrode, wherein said gate insulating film includes a first part corresponding to a central portion of a lower part of said gate electrode and a second part corresponding to an edge portion of the lower part of said gate electrode, said second part has a contoured shape widening vertically so as to increase its thickness from a portion for engagement with said first part, a contoured shape in a state that said spacer insulating film engages said second part of said gate insulating film is in a continuous form of at least an inclination having a first angle corresponding to a tilt angle of a side lower part of said gate electrode and an inclination having a second angle with respect to a main surface of said semiconductor substrate on an upper side of said second part of said gate insulating film, said first angle is greater than said second angle, and the side surface of said gate electrode has a contoured shape curved in a continuous form such that an upper main surface of said gate electrode is wider than a lower main surface.
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Abstract
Provided is an MOS transistor capable of reducing gate overlap capacitance without decreasing the driving current of the MOS transistor. Specifically, a double-angle smile oxidation structure is obtainable by curving the side surface of a gate electrode (22) so as to widen upwardly, and thickening the edge portion of a gate oxide film (21) by re-oxidation. The impurity concentration of a source/drain layer under the double-angle smile oxidation structure (a region around point B) is set to the range of 4×1018 cm−3±40%.
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9 Claims
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1. A semiconductor device including an MOS transistor comprising:
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a semiconductor substrate;
a gate insulating film selectively disposed on said semiconductor substrate;
a gate electrode selectively disposed on said gate insulating film; and
a spacer insulating film disposed on a side surface of said gate electrode, wherein said gate insulating film includes a first part corresponding to a central portion of a lower part of said gate electrode and a second part corresponding to an edge portion of the lower part of said gate electrode, said second part has a contoured shape widening vertically so as to increase its thickness from a portion for engagement with said first part, a contoured shape in a state that said spacer insulating film engages said second part of said gate insulating film is in a continuous form of at least an inclination having a first angle corresponding to a tilt angle of a side lower part of said gate electrode and an inclination having a second angle with respect to a main surface of said semiconductor substrate on an upper side of said second part of said gate insulating film, said first angle is greater than said second angle, and the side surface of said gate electrode has a contoured shape curved in a continuous form such that an upper main surface of said gate electrode is wider than a lower main surface. - View Dependent Claims (2, 3, 4)
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5. A semiconductor device including an MOS transistor comprising:
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a semiconductor substrate;
a gate insulating film selectively disposed on said semiconductor substrate;
a gate electrode selectively disposed on said gate insulating film; and
a spacer insulating film disposed on a side surface of said gate electrode, wherein said gate insulating film includes a first part corresponding to a central portion of a lower part of said gate electrode and a second part corresponding to an edge portion of the lower part of said gate electrode, said second part has a contoured shape widening upwardly so as to increase its thickness from a portion for engagement with said first part and also curving so as to project outwardly. - View Dependent Claims (6, 7, 8, 9)
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Specification