Semiconductor device and method for manufacturing the same
First Claim
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1. A semiconductor device, comprising:
- a first trench provided in a semiconductor substrate of a first conductivity type;
a first semiconductor layer of the first conductivity type having an impurity concentration lower than that of the semiconductor substrate, a second semiconductor layer of a second conductivity type, and a third semiconductor layer of the first conductivity type having an impurity concentration higher than that of the first semiconductor layer, the first to third semiconductor layers being formed in a stacked manner to cover the first trench;
a second trench provided in the third semiconductor layer in such a manner that the second trench at least partially penetrates the third semiconductor layer to expose the second semiconductor layer in a vertical direction relative to a plane of the semiconductor substrate, and at least partially penetrates the third semiconductor layer to expose the second semiconductor layer in a horizontal direction relative to the plane of the semiconductor substrate;
a fourth semiconductor layer of the second conductivity type having an impurity concentration higher than that of the second semiconductor layer, the fourth semiconductor layer being formed to cover the second trench;
third trenches arranged between portions of the fourth semiconductor layer in such a manner as to be spaced apart from the side of the fourth semiconductor layer, the third trenches being provided so that each of the trenches penetrates the third semiconductor layer to expose the second semiconductor layer or penetrates the third and second semiconductor layers to expose the first semiconductor layer in the vertical direction relative to the plane of the semiconductor substrate, and so that each of the trenches penetrates the second semiconductor layer to expose the first semiconductor layer on one end or penetrates the second and first semiconductor layers to expose the semiconductor substrate on one end and to expose the third semiconductor layer on the other end in the horizontal direction relative to the plane of the semiconductor substrate; and
trench gates formed to cover the third trenches, each trench gate including a gate insulating film and a gate electrode film formed in a stacked manner.
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Abstract
According to an embodiment, a semiconductor device includes a first trench being provided in an N+ substrate. An N layer, an N− layer, a P layer, and an N+ layer are formed in a stacked manner to cover the first trench. The semiconductor device includes second and third trenches. The P+ layer is formed to cover the second trench. The trench gates are formed to cover the third trenches.
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Citations
20 Claims
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1. A semiconductor device, comprising:
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a first trench provided in a semiconductor substrate of a first conductivity type; a first semiconductor layer of the first conductivity type having an impurity concentration lower than that of the semiconductor substrate, a second semiconductor layer of a second conductivity type, and a third semiconductor layer of the first conductivity type having an impurity concentration higher than that of the first semiconductor layer, the first to third semiconductor layers being formed in a stacked manner to cover the first trench; a second trench provided in the third semiconductor layer in such a manner that the second trench at least partially penetrates the third semiconductor layer to expose the second semiconductor layer in a vertical direction relative to a plane of the semiconductor substrate, and at least partially penetrates the third semiconductor layer to expose the second semiconductor layer in a horizontal direction relative to the plane of the semiconductor substrate; a fourth semiconductor layer of the second conductivity type having an impurity concentration higher than that of the second semiconductor layer, the fourth semiconductor layer being formed to cover the second trench; third trenches arranged between portions of the fourth semiconductor layer in such a manner as to be spaced apart from the side of the fourth semiconductor layer, the third trenches being provided so that each of the trenches penetrates the third semiconductor layer to expose the second semiconductor layer or penetrates the third and second semiconductor layers to expose the first semiconductor layer in the vertical direction relative to the plane of the semiconductor substrate, and so that each of the trenches penetrates the second semiconductor layer to expose the first semiconductor layer on one end or penetrates the second and first semiconductor layers to expose the semiconductor substrate on one end and to expose the third semiconductor layer on the other end in the horizontal direction relative to the plane of the semiconductor substrate; and trench gates formed to cover the third trenches, each trench gate including a gate insulating film and a gate electrode film formed in a stacked manner. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10)
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11. A semiconductor device, comprising:
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a first trench provided in a semiconductor substrate of a first conductivity type; a first semiconductor layer of a second conductivity type, a second semiconductor layer of the second conductivity type having an impurity concentration lower than that of the first semiconductor layer, a third semiconductor layer of the first conductivity type having an impurity concentration lower than that of the semiconductor substrate, and a fourth semiconductor layer of the second conductivity type having an impurity concentration higher than that of the second semiconductor layer, the first to fourth semiconductor layers being formed in a stacked manner to cover the first trench; a second trench provided in the fourth semiconductor layer in such a manner that the second trench at least partially penetrates the fourth semiconductor layer to expose the third semiconductor layer in a vertical direction relative to a plane of the semiconductor substrate, and at least partially penetrates the fourth semiconductor layer to expose the third semiconductor layer in a horizontal direction relative to the plane of the semiconductor substrate; a fifth semiconductor layer of the first conductivity type having an impurity concentration higher than that of the third semiconductor layer, the fifth semiconductor layer being formed to cover the second trench; third trenches arranged between portions of the fifth semiconductor layer in such a manner as to be spaced apart from the side of the fifth semiconductor layer, the third trenches being provided so that each of the trenches penetrates the fourth semiconductor layer to expose the third semiconductor layer or penetrates the fourth and third semiconductor layers to expose the second semiconductor layer in the vertical direction relative to the plane of the semiconductor substrate, and so that each of the trenches penetrates the third semiconductor layer to expose the second semiconductor layer on one end or penetrates the third and second semiconductor layers to expose the first semiconductor layer on one end and to expose the fourth semiconductor layer on the other end in the horizontal direction relative to the plane of the semiconductor substrate; and trench gates formed to cover the third trenches, each trench gate including a gate insulating film and a gate electrode film formed in a stacked manner. - View Dependent Claims (12, 13, 14, 15)
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16. A method for manufacturing a semiconductor device, comprising the steps of:
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forming a first trench in a semiconductor substrate of a first conductivity type, the first trench having a quadrangular prism shape elongated in a horizontal direction relative to a plane of the semiconductor substrate; forming a first semiconductor layer of the first conductivity type having an impurity concentration lower than that of the semiconductor substrate, a second semiconductor layer of a second conductivity type, and a third semiconductor layer of the first conductivity type having an impurity concentration higher than that of the first semiconductor layer, the first to third semiconductor layers being formed in a stacked manner to cover the first trench; polishing the first to third semiconductor layers to be flattened so that the semiconductor substrate is exposed; forming a second trench in the third semiconductor layer in such a manner that the second trench at least partially penetrates the third semiconductor layer to expose the second semiconductor layer in a vertical direction relative to the plane of the semiconductor substrate, and at least partially penetrates the third semiconductor layer to expose the second semiconductor layer in the horizontal direction relative to the plane of the semiconductor substrate; forming a fourth semiconductor layer of the second conductivity type having an impurity concentration higher than that of the second semiconductor layer, the fourth semiconductor layer being formed to cover the second trench; polishing the fourth semiconductor layer to be flattened so that the semiconductor substrate is exposed; forming third trenches in such a manner that the third trenches are spaced apart from the fourth semiconductor layer, the third trenches being formed so that each of the trenches penetrates the third and second semiconductor layers formed in the stacked manner to expose the first semiconductor layer in the vertical direction relative to the plane of the semiconductor substrate, and so that each of the trenches penetrates the second semiconductor layer to expose the first semiconductor layer or the semiconductor substrate on one end and to expose the third semiconductor layer on the other end in the horizontal direction relative to the plane of the semiconductor substrate; and forming trench gates in such a manner that the trench gates cover the third trenches, each trench gate including a gate insulating film and a gate electrode film. - View Dependent Claims (17, 18, 19, 20)
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Specification