Insulated gate semiconductor device and method for manufacturing the same
There is provided a structure wherein an emitter layer 3 is provided in the region A on the first major surface side of a semiconductor substrate 1 , and emitter layer 3 is not provided in the region b. There is provided a structure wherein a collector P layer 5 is provided in the region A on the second major surface side of a semiconductor substrate 1 , and a cathode N layer 4 is provided in the region B. Specifically, there is provided a structure wherein IGBTs are composed in the region A, and diodes are composed in the region B. By the above-described structure, ON characteristics when the gate is turned on can be improved while suppressing the elevation of the forward voltage Vf and the recovery current of the diodes.
1. An insulated gate semiconductor device comprising:
a semiconductor substrate of a first conductivity type having a first major surface and a second major surface,
a first semiconductor layer of a second conductivity type provided on the first major surface of the semiconductor substrate in the vicinity of at least one first region of the semiconductor substrate and at least one second region of the semiconductor substrate adjacent to the first region,
a plurality of first trenches provided in the first region and penetrating the first semiconductor layer from the first major surface of the semiconductor substrate,
a second semiconductor layer of the first conductivity type selectively provided in the vicinity of the plurality of first trenches on the first major surface of the semiconductor substrate and in the first region,
an insulating film coating the inner surfaces of the plurality of first trenches,
a conductive film buried in the first trenches through the insulating film,
a first major electrode provided on the first semiconductor layer and the second semiconductor layer, and electrically connected to the first semiconductor layer,
an entire third semiconductor layer of the second conductivity type provided on the second major surface of the semiconductor substrate and aligned with the first region,
a fourth semiconductor layer of the first conductivity type provided on the second major surface of the semiconductor substrate, and
a second major electrode coating the third semiconductor layer and the fourth semiconductor layer, and provided on the second major surface of the semiconductor substrate.
2. The insulated gate semiconductor device according to claim 1 , further comprising:
a plurality of second trenches provided in the second region and penetrating the first semiconductor layer from the first major surface of the semiconductor substrate,
an insulating film coating the inner surfaces of the plurality of second trenches, and
a conductive film buried in the second trenches through the insulating film.
3. The insulated gate semiconductor device according to claim 1 , wherein
the width of the first region is larger than the width of the second region.
4. The insulated gate semiconductor device according to claim 2 , wherein
the distance between each of the plurality of first trenches is not more than 10 μm, and the distance between each of the plurality of second trenches is not more than 10 μm.
5. The insulated gate semiconductor device according to claim 3 , wherein
the width of the first region and the width of the second region is not less than 50 μm.
6. The insulated gate semiconductor device according to claim 1 , further comprising:
a fifth semiconductor layer of the first conductivity type contacting the first semiconductor layer on a side of the first semiconductor layer other than a side of the first semiconductor layer on the first major surface of the semiconductor substrate, and having a higher impurity concentration than an impurity concentration of the semiconductor substrate.
7. The insulated gate semiconductor device according to claim 1 , wherein
the third semiconductor layer is provided on the second major surface side of the semiconductor substrate in a location facing the second semiconductor layer of the first region, and
the fourth semiconductor layer is provided on the second major surface side of the semiconductor substrate in a location facing the first semiconductor layer of the second region.
8. The insulated gate semiconductor device according to claim 1 , wherein
the impurity concentration of the first semiconductor layer provided in the second region is lower than the impurity concentration of the first semiconductor layer provided in the first region.
9. The insulated gate semiconductor device according to claim 2 , wherein
the plurality of first trenches in the first region are evenly spaced at a first distance,
the plurality of second trenches in the second region are evenly spaced at a second distance, and
the second distance is smaller than the first distance.