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US 11,107,912 B2Granted
Trench gate semiconductor device with dummy gate electrode and manufacturing method of the same
AssigneeRenesas Electronics Corporation
InventorsYoshito Nakazawa, Yuji Yatsuda
Life of this patent
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Abstract
A semiconductor device including a field-effect transistor having source and drain source regions, first and second gate electrodes and a protective diode connected to the transistor. The first gate electrode is formed over a first gate insulating film in a lower part of a trench. The second gate electrode is formed over a second gate insulating film in an upper part of the trench. The first gate electrode includes a first polysilicon film, and the second gate electrode includes a second polysilicon film, wherein an impurity concentration of the first polysilicon film is lower than an impurity concentration of the second polysilicon film.
Claims12
A semiconductor device comprising:
- a semiconductor substrate having a main surface and a back surface opposite to the main surface;
- a source region formed on the main surface of the semiconductor substrate;
- a drain region formed on the back surface of the semiconductor substrate;
- a trench formed in the semiconductor substrate so as to extend from an upper surface of the source region in a thickness direction of the semiconductor substrate;
- a first insulating film formed at a lower part of an inside of the trench;
- a dummy gate electrode formed via the first insulating film at the lower part of the inside of the trench;
- a gate insulating film formed on an inner surface of the trench;
- and
- a gate electrode formed via the gate insulating film at an upper part of the inside of the trench,
- wherein, in the thickness direction of the semiconductor substrate, a distance between the main surface of the semiconductor substrate and a lower end of the gate electrode is greater than a distance between the main surface of the semiconductor substrate and an upper end of the dummy gate electrode,
- wherein a thickness of the first insulating film is greater than a thickness of the gate insulating film, and
- wherein a width of a lower end of the dummy gate electrode is greater than a width of the upper end of the dummy gate electrode.
9 more elements
A semiconductor device comprising:
- a semiconductor substrate having a main surface and a back surface opposite to the main surface;
- a source region formed on the main surface of the semiconductor substrate;
- a drain region formed on the back surface of the semiconductor substrate;
- a trench formed in the semiconductor substrate so as to extend from an upper surface of the source region in a thickness direction of the semiconductor substrate;
- a first insulating film formed at a lower part of an inside of the trench;
- a dummy gate electrode formed via the first insulating film at the lower part of the inside of the trench;
- a gate insulating film formed on an inner surface of the trench;
- and
- a gate electrode formed via the gate insulating film at an upper part of the inside of the trench,
- wherein, in the thickness direction of the semiconductor substrate, a distance between the main surface of the semiconductor substrate and a lower end of the gate electrode is greater than a distance between the main surface of the semiconductor substrate and an upper end of the dummy gate electrode,
- wherein a thickness of the first insulating film is greater than a thickness of the gate insulating film, and
- wherein a concentration of impurities introduced into the gate electrode is higher than a concentration of impurities introduced into the dummy gate electrode.
9 more elements
A semiconductor device comprising:
- a semiconductor substrate having a main surface and a back surface opposite to the main surface;
- a source region formed on the main surface of the semiconductor substrate;
- a drain region formed on the back surface of the semiconductor substrate;
- a trench formed in the semiconductor substrate so as to extend from an upper surface of the source region in a thickness direction of the semiconductor substrate;
- a first insulating film formed at a lower part of an inside of the trench;
- a dummy gate electrode formed via the first insulating film at the lower part of the inside of the trench;
- a gate insulating film formed on an inner surface of the trench;
- and
- a gate electrode formed via the gate insulating film at an upper part of the inside of the trench,
- wherein, in the thickness direction of the semiconductor substrate, a distance between the main surface of the semiconductor substrate and a lower end of the gate electrode is greater than a distance between the main surface of the semiconductor substrate and an upper end of the dummy gate electrode, and
- wherein a thickness of the first insulating film is greater than a thickness of the gate insulating film, and
- further comprising a protective diode electrically connected to the source region.
9 more elements
Dependencies are inferred from the claim text.