Semiconductor device and its manufacturing method
First Claim
1. A semiconductor device, comprising:
- at least one gate electrode formed over a semiconductor substrate having at least a portion with a reverse tapered shape when viewed in cross section;
a mask insulating film formed on a top surface of the at least one gate electrode;
a side surface insulating film formed on a side surface of the at least one gate electrode;
a side wall insulating film formed on a side surface of the mask insulating film and the at least one gate electrode;
a first impurity region formed in the semiconductor substrate with the at least one gate electrode and the side surface insulating film as a mask, and without the side wall insulating film as a mask; and
a second impurity region formed in the semiconductor substrate with at least the side wall insulating film as a mask, the second impurity region having a higher impurity concentration than the first impurity region.
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Accused Products
Abstract
A semiconductor device is disclosed that can include a gate electrode (6) having a lower layer (6a) and a higher layer (6b), a mask insulating film (7) formed over a higher layer (6b). A side surface insulating film (9) may be formed on sides of a gate electrode (6) and a side wall insulating film (8) may be formed on the sides of a gate electrode (6) and mask insulating film (7). A low density impurity region (3) may be formed with a gate electrode (6) and side surface insulating film (9) as a mask. A higher density impurity region (4) may be formed with a gate electrode (6) and side wall insulating film (8) as a mask. A contact plug (10) may be formed between side wall insulating films (8) that contacts a higher density impurity region (4). A gate electrode (6) may have a reverse tapered shape when viewed in cross section. A lower layer (6a) may have a reverse tapered shape and/or a side surface insulating film (9) may have a greater thickness on sides of a higher layer (6b) than on a lower layer (6a).
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Citations
20 Claims
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1. A semiconductor device, comprising:
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at least one gate electrode formed over a semiconductor substrate having at least a portion with a reverse tapered shape when viewed in cross section;
a mask insulating film formed on a top surface of the at least one gate electrode;
a side surface insulating film formed on a side surface of the at least one gate electrode;
a side wall insulating film formed on a side surface of the mask insulating film and the at least one gate electrode;
a first impurity region formed in the semiconductor substrate with the at least one gate electrode and the side surface insulating film as a mask, and without the side wall insulating film as a mask; and
a second impurity region formed in the semiconductor substrate with at least the side wall insulating film as a mask, the second impurity region having a higher impurity concentration than the first impurity region. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 14, 16, 17, 19, 20)
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13. A method of manufacturing a semiconductor device, comprising the steps of:
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forming a gate electrode with a mask insulating film thereon, the gate electrode including a reverse tapered shape when viewed in cross section;
forming a side surface insulating film on sides of the gate electrode;
forming a first impurity region in a semiconductor substrate with the gate electrode and the side surface insulating film as a mask;
forming a side wall insulating film on a side surface of the mask insulating film and the gate electrode; and
forming a second impurity region in the semiconductor substrate with at least the side wall insulating film as a mask, the second impurity region having a higher impurity concentration than the first impurity region.
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15. The method of 14, wherein:
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the laminated gate electrode includes a higher layer over the lower layer; and
forming the side surface insulating film includes forming a thicker side surface insulating film on the sides of the higher layer than on the sides of the lower layer.
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18. A method, comprising the steps of:
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forming a gate electrode that has a reverse tapered shape when viewed in cross section; and
tilt implanting ions with the gate electrode as an implant mask to form a first impurity region; and
implanting ions with the gate electrode and an insulating side wall as an implant mask to form a second impurity region, the insulating side wall being formed over the first impurity region, and the second impurity region having a higher concentration of implanted ions than the first impurity region.
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Specification