Semiconductor device and method for manufacturing same
A semiconductor device includes a semiconductor part, first to third electrodes, and a control electrode. The first electrode is provided on a back surface of the semiconductor part. The second electrode is provided at a front surface side of the semiconductor part. The third electrode and the control electrode are provided inside a trench of the semiconductor part. The control electrode includes first and second control portions. The semiconductor device further includes first to third insulating films. The first insulating film is between the control electrode and the semiconductor part. The second insulating film covers the first and second control portions. The third insulating film is between the second electrode and the second insulating film. The third insulating film includes a portion extending between the first and second control portions. The third electrode is between the first electrode and the extension portion of the third insulating film.
1. A semiconductor device, comprising:
a semiconductor part including a first semiconductor layer of a first conductivity type, a second semiconductor layer of a second conductivity type, and a third semiconductor layer of the first conductivity type;
a first electrode provided on a back surface of the semiconductor part;
a second electrode provided at a front surface side of the semiconductor part, the first semiconductor layer extending between the first electrode and the second electrode, the second semiconductor layer being provided between the first semiconductor layer and the second electrode, the third semiconductor layer being provided between the second semiconductor layer and the second electrode;
a control electrode inside the semiconductor part, the control electrode including a first control portion and a second control portion arranged in a first direction, the first direction being directed along a boundary between the first electrode and the semiconductor part, the control electrode further including a connection portion, the first and second control portions being joined together at the connection portion;
a first insulating film provided between the second semiconductor layer of the semiconductor part and the first control portion or the second control portion of the control electrode;
a second insulating film provided between the first control portion and the second control portion of the control electrode, the second insulating film covering the first and second control portions;
a third insulating film including first to third portions,
the first portion being provided between the first control portion and the second electrode,
the second portion being provided between the second control portion and the second electrode, and
the third portion being provided between the first portion and the second portion, the third portion extending between the first control portion and the second control portion, the second insulating film being provided between the control electrode and the third insulating film;
a third electrode extending in a second direction, the second direction being directed from the first electrode toward the second electrode, the third electrode being provided between the first electrode and the third portion of the third insulating film and between the first electrode and the connection portion of the control electrode;
a fourth insulating film provided between the first semiconductor layer and the third electrode, the first and second control portions of the control electrode being provided between the second electrode and the fourth insulating film;
a fifth insulating film provided between the third electrode and the third portion of the third insulating film and between the third electrode and the connection portion of the control electrode; and
a sixth insulating film provided between the fifth insulating film and the connection portion of the control electrode, the sixth insulating film including a different material from a material of the fifth insulating film.
2. The device according to claim 1 , wherein
a distance from the third electrode to the first electrode is less than a distance from the control electrode to the first electrode.
3. The device according to claim 1 , wherein
the sixth insulating film is silicate glass including boron and phosphorus.
4. The device according to claim 1 , wherein
the third electrode includes an extension portion extending in the second direction,
the third electrode is electrically connected to the second electrode at the extension portion,
the extension portion is positioned at a level same as the control electrode in the second direction, and
the fifth insulating film and the sixth insulating film extend between the extension portion and the control electrode.
5. The device according to claim 1 , wherein
the second insulating film includes a portion positioned between the third electrode and the third insulating film, and
the portion of the second insulating film extends in the fourth insulating film.
6. The device according to claim 5 , wherein
the fifth insulating film is provided between the third electrode and the second insulating film.
7. The device according to claim 1 , wherein
the third insulating film is silicate glass including boron and phosphorus.
8. The device according to claim 1 , wherein
the first and second control portions of the control electrode contact the fourth insulating film,
the first and second control portions each have a first width in the first direction,
the fourth insulating film has a second width in the first direction at a portion contacting the control electrode, and
the second width is greater than the first width.
9. The device according to claim 1 , wherein
the first and second control portions of the control electrode include end portions at the second electrode side, and
the end portions are oblique to a wall surface of the forth insulating film.