Semiconductor device
A semiconductor device includes a semiconductor part, first to fourth electrodes, and first and second insulating film. The first and second electrodes are provided on back and front surfaces of the semiconductor part, respectively. The third and fourth electrodes each extend into the semiconductor device form the front surface side. The third and fourth electrodes are electrically insulated from the semiconductor part by insulating films. The semiconductor part includes first to fourth layers. The first layer of a first conductivity type extends between the first and second electrodes. The second layer of a second conductivity type is provided between the first layer and the second electrode. The third layer of the second conductivity type is partially provided between the second layer and the second electrode. The fourth layer of the first conductivity type is provided in the second layer. The fourth layer is apart from the third layer.
1 . A semiconductor device, comprising:
a semiconductor part including first to fourth semiconductor layers;
a first electrode provided on a back surface of the semiconductor part;
a second electrode provided on a front surface of the semiconductor part, the front surface being at a side opposite to the back surface;
a third electrode provided in a first trench and extending into the semiconductor part from the front surface side of the semiconductor part;
a first insulating film provided between the semiconductor part and the third electrode, the first insulating film electrically insulating the third electrode from the semiconductor part;
a fourth electrode provided in a second trench and extending into the semiconductor part from the front surface side of the semiconductor part, the second trench provided at a position next to the first trench; and
a second insulating film provided between the semiconductor part and the fourth electrode, the second insulating film electrically insulating the fourth electrode from the semiconductor part,
the first semiconductor layer of a first conductivity type extending between the first electrode and the second electrode,
the second semiconductor layer of a second conductivity type being provided between the first semiconductor layer and the second electrode and extending between the third electrode and the fourth electrode,
the third semiconductor layer of the second conductivity type being partially provided on the second semiconductor layer between the second semiconductor layer and the second electrode, the third semiconductor layer including a second-conductivity-type impurity with a higher concentration than the second semiconductor layer, the third semiconductor layer directly contacting the first insulating film,
the fourth semiconductor layer of the first conductivity type being provided in the second semiconductor layer between the third electrode and the fourth electrode, the fourth semiconductor layer being apart from the third semiconductor layer, the second semiconductor layer extending between the third semiconductor layer and the fourth semiconductor layer,
a bottom of the fourth semiconductor layer on a side toward the back surface of the semiconductor part being spaced apart from the first semiconductor layer,
the second semiconductor layer extending between the first semiconductor layer and the fourth semiconductor layer,
the second electrode being connected to the second and third semiconductor layers at the front surface of the semiconductor part, and
the third semiconductor layer directly contacting the second electrode.
2 . The device according to claim 1 , wherein
the fourth semiconductor layer directly contacts at least one of the first insulating film or the second insulating film.
3 . The device according to claim 1 , wherein
the semiconductor part further includes a second-third semiconductor layer partially provided on the second semiconductor layer between the second electrode and the second semiconductor layer, the second-third semiconductor layer directly contacting the second insulating film.
4 . The device according to claim 3 , wherein
the semiconductor part further includes a second-fourth semiconductor layer provided in the second semiconductor layer, the fourth semiconductor layer directly contacting the first insulating film, the second-fourth semiconductor layer contacting the second insulating film.
5 . The device according to claim 4 , wherein
the second semiconductor layer extends between the fourth semiconductor layer and the second-fourth semiconductor layer.
6 . The device according to claim 1 , wherein
the semiconductor part further includes a second-third semiconductor layer partially provided on the second semiconductor layer between the second electrode and the second semiconductor layer, and
the third semiconductor layer and the second-third semiconductor layer are apart from each other.
7 . The device according to claim 6 , wherein
the semiconductor part further includes a second-fourth semiconductor layer provided in the second semiconductor layer, and
the fourth semiconductor layer and the second-fourth semiconductor layer are apart from each other.
8 . The device according to claim 1 , wherein
the semiconductor part further includes fifth and sixth semiconductor layers,
the fifth semiconductor layer of the first conductivity type being provided between the first semiconductor layer and the first electrode, the fifth semiconductor layer including a first-conductivity-type impurity with a higher concentration than a concentration of the first-conductivity-type impurity in the first semiconductor layer,
the sixth semiconductor layer of the first conductivity type being partially provided on the second semiconductor layer between the second semiconductor layer and the second electrode, and
the third semiconductor layer and the sixth semiconductor layer are arranged on the second semiconductor layer and connected to the second electrode.
9 . The device according to claim 8 , wherein
the sixth semiconductor layer is provided between the third semiconductor layer and the first insulating film, and
the fourth semiconductor layer is positioned between the first semiconductor layer and the sixth semiconductor layer.
10 . The device according to claim 8 , wherein
the semiconductor part further includes a second-third semiconductor layer and a second-sixth semiconductor layer each provided on the second semiconductor layer between the second electrode and the second semiconductor layer,
the third semiconductor layer being provided between the sixth semiconductor layer and the first insulating film,
the second-third semiconductor layer being provided between the second-sixth semiconductor layer and the second insulating film, and
the second semiconductor layer extends between the sixth semiconductor layer and the second-sixth semiconductor layer and is connected to the second electrode.
11 . The device according to claim 10 , wherein
the third semiconductor layer and the sixth semiconductor layer contact the first insulating film; and the second-third semiconductor layer and the second-sixth semiconductor layer contact the second insulating film.
12 . The device according to claim 1 , wherein
the semiconductor part further includes a second-fourth semiconductor layer provided in the second semiconductor layer,
the fourth semiconductor layer and the second-fourth semiconductor layer are apart from each other, and
the second semiconductor layer extends between the fourth semiconductor layer and the second-fourth semiconductor layer.
13 . The device according to claim 1 , wherein
the fourth semiconductor layer directly contacts the first insulating film, and
the second semiconductor layer extends between the fourth semiconductor layer and the second insulating film.
14 . The device according to claim 1 , wherein
the entire third semiconductor layer is of the second conductivity type.
15 . A semiconductor device, comprising:
a semiconductor part including first to fourth semiconductor layers;
a first electrode provided on a back surface of the semiconductor part;
a second electrode provided on a front surface of the semiconductor part, the front surface being at a side opposite to the back surface;
a third electrode provided in a first trench and extending into the semiconductor part from the front surface side of the semiconductor part;
a first insulating film provided between the semiconductor part and the third electrode, the first insulating film electrically insulating the third electrode from the semiconductor part;
a fourth electrode provided in a second trench and extending into the semiconductor part from the front surface side of the semiconductor part, the second trench provided at a position next to the first trench; and
a second insulating film provided between the semiconductor part and the fourth electrode, the second insulating film electrically insulating the fourth electrode from the semiconductor part,
the first semiconductor layer of a first conductivity type extending between the first electrode and the second electrode,
the second semiconductor layer of a second conductivity type being provided between the first semiconductor layer and the second electrode and extending between the third electrode and the fourth electrode,
the third semiconductor layer of the second conductivity type being partially provided on the second semiconductor layer between the second semiconductor layer and the second electrode, the third semiconductor layer including a second-conductivity-type impurity with a higher concentration than the second semiconductor layer,
the fourth semiconductor layer of the first conductivity type being provided in the second semiconductor layer between the third electrode and the fourth electrode, the fourth semiconductor layer being apart from the third semiconductor layer, the second semiconductor layer extending between the third semiconductor layer and the fourth semiconductor layer,
the second electrode being connected to the second and third semiconductor layers at the front surface of the semiconductor part, wherein
the semiconductor part further includes fifth and sixth semiconductor layers,
the fifth semiconductor layer of the first conductivity type being provided between the first semiconductor layer and the first electrode, the fifth semiconductor layer including a first-conductivity-type impurity with a higher concentration than a concentration of the first-conductivity-type impurity in the first semiconductor layer,
the sixth semiconductor layer of the first conductivity type being partially provided on the second semiconductor layer between the second semiconductor layer and the second electrode,
the third semiconductor layer and the sixth semiconductor layer are arranged on the second semiconductor layer and connected to the second electrode, and
the third semiconductor layer is provided between the sixth semiconductor layer and the first insulating film in a first direction along the front surface of the semiconductor part.
16 . The device according to claim 15 , wherein
the third semiconductor layer directly contacts the second electrode.
17 . The device according to claim 15 , wherein
the fourth semiconductor layer is longer than the third semiconductor layer in a second direction from the first electrode to the second electrode.
18 . The device according to claim 15 , wherein
the sixth semiconductor layer is provided between the second semiconductor layer and the third semiconductor layer in the first direction.
19 . The device according to claim 15 , wherein
a bottom of the sixth semiconductor layer on a side toward the back surface of the semiconductor part directly contacts the second semiconductor layer.
20 . The device according to claim 15 , wherein
the semiconductor part further includes a second-third semiconductor layer and a second-sixth semiconductor layer each provided on the second semiconductor layer between the second electrode and the second semiconductor layer,
the second-third semiconductor layer is provided between the second-sixth semiconductor layer and the second insulating film in the first direction, and
the second semiconductor layer extends between the sixth semiconductor layer and the second-sixth semiconductor layer and is connected to the second electrode.