Semiconductor device and method for manufacturing same

A semiconductor device comprising:

• a semiconductor substrate member with a plurality of trenches formed in an upper surface;
• a gate electrode provided in the trench;
• a gate insulating film provided between the semiconductor substrate member and the gate electrode;
• a first electrode connected to the upper surface of the semiconductor substrate member;
• and
• a second electrode connected to a lower surface of the semiconductor substrate member,
• the semiconductor substrate member including:
• a second semiconductor layer of a first conductivity type connected to the second electrode, a lower end portion of the gate electrode extending into the second semiconductor layer;
• a base layer of a second conductivity type provided on the second semiconductor layer, the gate electrode penetrating through the base layer;
• a first semiconductor layer of the first conductivity type provided on the base layer and connected to the first electrode;
• and
• a carrier ejection layer of the second conductivity type provided in a region spaced from the gate insulating film between the trenches, the carrier ejection layer being connected to the first electrode and having a higher effective impurity concentration than the base layer, and
• the first semiconductor layer including:
• a lower section formed from monocrystalline silicon;
• and
• an upper section having a higher impurity concentration than the lower section and formed from polycrystalline silicon.

A semiconductor device comprising:

• a semiconductor substrate member with a plurality of elongated projections formed in an upper surface;
• an insulating member buried in the semiconductor substrate member and having an upper portion located in each of the elongated projections;
• a gate electrode provided immediately below the insulating member;
• a gate insulating film provided between the semiconductor substrate member and the gate electrode;
• a first electrode connected to the upper surface of the semiconductor substrate member;
• and
• a second electrode connected to a lower surface of the semiconductor substrate member,
• the semiconductor substrate member including:
• a second semiconductor layer of a first conductivity type connected to the second electrode, a lower end portion of the gate electrode extending into the second semiconductor layer;
• a base layer of a second conductivity type provided on the second semiconductor layer, the gate electrode penetrating through the base layer;
• a first semiconductor layer of the first conductivity type provided on the base layer, covering an upper surface of the insulating member, and being in contact with the first electrode;
• and
• a carrier ejection layer of the second conductivity type provided immediately below a region between the elongated projections, being in contact with the first semiconductor layer and the base layer, and having a higher effective impurity concentration than the base layer.

A semiconductor device comprising:

• a semiconductor substrate member with a plurality of trenches formed in an upper surface;
• a gate electrode provided in the trench;
• a gate insulating film provided between the semiconductor substrate member and the gate electrode;
• a first electrode connected to the upper surface of the semiconductor substrate member;
• and
• a second electrode connected to a lower surface of the semiconductor substrate member,
• the semiconductor substrate member including:
• a second semiconductor layer of a first conductivity type connected to the second electrode, a lower end portion of the gate electrode extending into the second semiconductor layer;
• a base layer of a second conductivity type provided on the second semiconductor layer, the gate electrode penetrating through the base layer;
• a first semiconductor layer of the first conductivity type provided on the base layer and connected to the first electrode;
• and
• a carrier ejection layer of the second conductivity type provided in a region spaced from the gate insulating film between the trenches, the carrier ejection layer being connected to the first electrode and having a higher effective impurity concentration than the base layer, and
• impurity concentration profile along a vertical direction in the first semiconductor layer including a point where impurity concentration discontinuously changes, and the impurity concentration above the point being higher than the impurity concentration below the point.

A semiconductor device comprising:

• a semiconductor substrate member made of silicon with a plurality of trenches formed in an upper surface;
• a gate electrode provided in the trench;
• a gate insulating film provided between the semiconductor substrate member and the gate electrode;
• a silicide film in contact with the upper surface of the semiconductor substrate member;
• a first electrode in contact with an upper surface of the silicide film;
• and
• a second electrode connected to a lower surface of the semiconductor substrate member,
• the semiconductor substrate member including:
• a second semiconductor layer of a first conductivity type connected to the second electrode, a lower end portion of the gate electrode extending into the second semiconductor layer;
• a base layer of a second conductivity type provided on the second semiconductor layer, the gate electrode penetrating through the base layer;
• a first semiconductor layer of the first conductivity type having a lower effective impurity concentration than the silicide film, provided on the base layer, and being in contact with the silicide film;
• and
• a carrier ejection layer of the second conductivity type provided in a region spaced from the gate insulating film between the trenches, the carrier ejection layer being connected to the first electrode and having a higher effective impurity concentration than the base layer, and
• in impurity concentration profile along a vertical direction in the silicide film and the first semiconductor layer, impurity concentration discontinuously changes at an interface between the silicide film and the first semiconductor layer.