Semiconductor device and method of manufacturing semiconductor device
AssigneeFuji Electric Co., Ltd.
InventorTakeyoshi Nishimura
Life of this patent
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Abstract
A semiconductor layer may be subjected to etching to form a trench therein. An epitaxial layer may be further formed in the trench. Here, the impurity concentration of the epitaxial layer is controlled to be lower than that of the semiconductor layer. In this manner, concentration of electrical fields in the trench is reduced. A first innovations herein provides a semiconductor device including a first semiconductor layer containing impurities of a first conductivity type, a trench provided in the first semiconductor layer on a front surface side thereof, and a second semiconductor layer provided on an inner wall of the trench, where the second semiconductor layer contains impurities of the first conductivity type at a lower concentration than the first semiconductor layer.
Claims11
A semiconductor device comprising:
- a semiconductor substrate containing impurities of a first conductivity type;
- a first semiconductor layer on a front surface of the semiconductor substrate, the first semiconductor layer containing impurities of a first conductivity type at a lower concentration than the impurities of the semiconductor substrate;
- a trench provided in the first semiconductor layer on a front surface side thereof;
- and
- a second semiconductor layer provided on an inner wall of the trench, the second semiconductor layer containing impurities of the first conductivity type at a lower concentration than the first semiconductor layer,
- wherein
- an area of the semiconductor device occupied by the semiconductor substrate from a schematic top view is divided between an active portion and a surrounding portion;
- the surrounding portion surrounds the active portion from the schematic top view;
- the surrounding portion does not include any trenches;
- the surrounding portion includes a LOCOS region such that the active portion and the LOCOS region do not overlap;
- and
- the second semiconductor layer extends to outer edges of the semiconductor substrate from the schematic top view.
A semiconductor device comprising:
- a semiconductor substrate containing impurities of a first conductivity type;
- a first semiconductor layer on a front surface of the semiconductor substrate, the first semiconductor layer containing impurities of a first conductivity type at a lower concentration than the impurities of the semiconductor substrate;
- a trench provided in the first semiconductor layer on a front surface side thereof;
- and
- a second semiconductor layer provided on an inner side wall and an inner base wall of the trench, the second semiconductor layer containing impurities of the first conductivity type at a lower concentration than the first semiconductor layer,
- wherein
- an area of the semiconductor device occupied by the semiconductor substrate from a schematic top view is divided between an active portion and a surrounding portion;
- the surrounding portion surrounds the active portion from the schematic top view;
- the surrounding portion does not include any trenches;
- the surrounding portion includes a LOCOS region such that the active portion and the LOCOS region do not overlap;
- and
- the second semiconductor layer extends to outer edges of the semiconductor substrate from the schematic top view.
Dependencies are inferred from the claim text.