Semiconductor device having superjunction structure and method for manufacturing the same
First Claim
1. A semiconductor device comprising:
- a drift region of a first conductivity type including an active element region and a peripheral region formed around said active element region;
a first trench formed in said peripheral region;
a second trench formed in said active element region;
a gate insulating film and a gate electrode formed in each of said first and second trenches;
a base region of a second conductivity type formed at least in said active element region;
a plurality of column regions of said second conductivity type selectively formed separately from one another in each of said active element region and said peripheral region to thereby form a parallel p-n layer that comprises a portion of said drift region and selected ones of said column regions;
a source region of said first conductivity type formed in said base region; and
a guard region of said second conductivity type formed below at least a portion of said first trench closest to said active element region, said guard region being free from being formed below said second trench.
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Accused Products
Abstract
An n-type drift region includes an active element region and a peripheral region. A p-type base region is formed at least in the active element region. A trench-type gate electrode is formed in each of the active element region and the peripheral region. An n-type source region formed in the base region. A plurality of p-type column regions is selectively formed separately from one another in each of the active element region and the peripheral region. In a peripheral region, a p-type guard region is formed below the gate electrode. In the active element region, the p-type guard region is not formed below the gate electrode. As a result, it is possible to hold the breakdown voltage in the peripheral region at a higher level than in the active element region while maintaining the low ON resistance due to a superjunction structure and to raise the breakdown voltage performance of the semiconductor device.
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Citations
19 Claims
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1. A semiconductor device comprising:
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a drift region of a first conductivity type including an active element region and a peripheral region formed around said active element region; a first trench formed in said peripheral region; a second trench formed in said active element region; a gate insulating film and a gate electrode formed in each of said first and second trenches; a base region of a second conductivity type formed at least in said active element region; a plurality of column regions of said second conductivity type selectively formed separately from one another in each of said active element region and said peripheral region to thereby form a parallel p-n layer that comprises a portion of said drift region and selected ones of said column regions; a source region of said first conductivity type formed in said base region; and a guard region of said second conductivity type formed below at least a portion of said first trench closest to said active element region, said guard region being free from being formed below said second trench. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17)
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18. A method for manufacturing a semiconductor device, comprising:
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forming a drift region of a first conductivity type including an active element region and a peripheral region formed around said active element region; forming a first trench in said peripheral region; forming a guard region by introducing an impurity of a second conduction type into a bottom of said first trench; forming a second trench in said active element region; forming a gate insulating film in each of said first and second trenches; forming a gate electrode in each of said first and second trenches and forming a field electrode electrically connected to said gate electrode over said peripheral region; forming a plurality of column regions of said second conductivity type in each of said active element region and said peripheral region, forming a base region of said second conductivity type at least in said active element region; and forming a source region of said first conductivity type in said base region, wherein said field electrode is formed without covering at least one of said column regions formed in said peripheral region, said at least one of said column regions being closest to said active element region. - View Dependent Claims (19)
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Specification