Semiconductor device and manufacturing method of the same
First Claim
1. A semiconductor device including a field-effect transistor and a diode formed over the same semiconductor substrate, the semiconductor device comprising:
- a drain region of said field-effect transistor formed over the semiconductor substrate;
a channel forming region of said field-effect transistor formed over the drain region;
a source region of said field-effect transistor formed over the channel forming region;
a trench reaching the drain region from an upper surface of the source region;
a first insulating film formed in the trench;
a first conductive film formed over the first insulating film in the trench;
a gate insulating film of said field-effect transistor formed over the first insulating film in the trench;
a gate electrode of said field-effect transistor formed over the gate insulating film in the trench;
a second conductive film made of the same film as the first conductive film, and formed over the semiconductor substrate; and
an anode region and a cathode region of the diode formed in the second conductive film, wherein each of the anode region and the cathode region of the diode is electrically connected to the gate electrode or the source region of the field-effect transistor.
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Accused Products
Abstract
In a power MISFET having a trench gate structure with a dummy gate electrode, a technique is provided for improving the performance of the power MISFET, while preventing electrostatic breakdown of a gate insulating film therein. A power MISFET having a trench gate structure with a dummy gate electrode, and a protective diode are formed on the same semiconductor substrate. The protective diode is provided between a source electrode and a gate interconnection. In a manufacturing method of such a semiconductor device, a polycrystalline silicon film for the dummy gate electrode and a polycrystalline silicon film for the protective diode are formed simultaneously. A source region of the power MISFET and an n+-type semiconductor region of the protective diode are formed in the same step.
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Citations
26 Claims
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1. A semiconductor device including a field-effect transistor and a diode formed over the same semiconductor substrate, the semiconductor device comprising:
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a drain region of said field-effect transistor formed over the semiconductor substrate;
a channel forming region of said field-effect transistor formed over the drain region;
a source region of said field-effect transistor formed over the channel forming region;
a trench reaching the drain region from an upper surface of the source region;
a first insulating film formed in the trench;
a first conductive film formed over the first insulating film in the trench;
a gate insulating film of said field-effect transistor formed over the first insulating film in the trench;
a gate electrode of said field-effect transistor formed over the gate insulating film in the trench;
a second conductive film made of the same film as the first conductive film, and formed over the semiconductor substrate; and
an anode region and a cathode region of the diode formed in the second conductive film, wherein each of the anode region and the cathode region of the diode is electrically connected to the gate electrode or the source region of the field-effect transistor. - View Dependent Claims (2, 3, 4, 5)
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6. A semiconductor device comprising:
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(a) a field-effect transistor having a trench gate structure with a dummy gate electrode; and
(b) a protective diode, wherein the field-effect transistor and the protective diode are formed over the same semiconductor substrate. - View Dependent Claims (7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18)
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19. A method of manufacturing a semiconductor device, the semiconductor device including:
- a field-effect transistor having a trench gate structure with a dummy gate electrode; and
a protective diode,the method comprising a step of;
forming a polycrystalline silicon film for the protective diode, which is included in the protective diode, and a polycrystalline silicon film for the dummy gate electrode, which is included in the dummy gate electrode, in the same step. - View Dependent Claims (20)
- a field-effect transistor having a trench gate structure with a dummy gate electrode; and
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21. A method of manufacturing a semiconductor device, the method comprising the steps of:
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(a) forming a trench in a semiconductor substrate;
(b) forming an insulating film over the semiconductor substrate including an inner surface of the trench;
(c) forming a first polycrystalline silicon film over the insulating film;
(d) introducing an impurity into the first polycrystalline silicon film;
(e) annealing the first polycrystalline silicon film with the impurity introduced therein;
(f) forming, by patterning the first polycrystalline silicon film, a dummy gate electrode with a part of the first polycrystalline silicon film left in the trench, while forming an anode region of the protective diode over the semiconductor substrate;
(g) forming a gate insulating film over the semiconductor substrate including the trench;
(h) forming a second polycrystalline silicon film with a conductive impurity introduced therein over the gate insulating film;
(i) forming a gate electrode with a part of the second polycrystalline silicon film left in the trench by patterning the second polycrystalline silicon film;
(j) forming a semiconductor region for channel formation by introducing an impurity into a predetermined region of the semiconductor substrate;
(k) forming a source region by introducing an impurity into a predetermined region of the semiconductor substrate; and
(l) forming a cathode region of the protective diode by introducing an impurity into a predetermined region of the semiconductor substrate. - View Dependent Claims (22, 23, 24, 25, 26)
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Specification