Manufacturing method of semiconductor device
First Claim
1. A semiconductor device comprising:
- a semiconductor substrate having a principal surface of a first conductivity type;
a second conductivity type region, having an island shape, formed on the principal surface of said semiconductor substrate by introducing impurities of a second conductivity type by a plurality of ion implantation steps so as to have a smooth concentration profile in a depth direction of the semiconductor substrate;
a first conductivity type region formed inside said second conductivity type region by introducing impurities of the first conductivity type;
a trench formed in the semiconductor substrate extending from a surface of said first conductivity type region so as to reach at least said second conductivity type region on said first semiconductor substrate;
an insulation film formed on an inner wall surface of said trench; and
an electrode portion made of polycrystalline silicon filled in said trench with said insulation film interposed therebetween.
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Accused Products
Abstract
By improving profile of impurity concentration in a channel portion of an FET or an IGBT of a trench gate type, variation of threshold value is lessened, and a destruction caused by current concentration is prevented while suppressing deterioration of cut-off characteristics. An island of a base region of p-type is formed in a semiconductor substrate of n-type by carrying out high acceleration ion implantation twice followed by annealing, so that the impurity concentration profile in a channel portion changes gradually in a depth direction. Accordingly, it is possible to lessen variation of the threshold value and to reduce pinch resistance while at the same time improving sub-threshold voltage coefficient and conductance characteristics.
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Citations
28 Claims
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1. A semiconductor device comprising:
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a semiconductor substrate having a principal surface of a first conductivity type;
a second conductivity type region, having an island shape, formed on the principal surface of said semiconductor substrate by introducing impurities of a second conductivity type by a plurality of ion implantation steps so as to have a smooth concentration profile in a depth direction of the semiconductor substrate;
a first conductivity type region formed inside said second conductivity type region by introducing impurities of the first conductivity type;
a trench formed in the semiconductor substrate extending from a surface of said first conductivity type region so as to reach at least said second conductivity type region on said first semiconductor substrate;
an insulation film formed on an inner wall surface of said trench; and
an electrode portion made of polycrystalline silicon filled in said trench with said insulation film interposed therebetween. - View Dependent Claims (2, 11, 12, 13, 14)
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3. A semiconductor device comprising:
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a semiconductor substrate having a principal surface of a first conductivity type;
a second conductivity type region formed on the principal surface of said semiconductor substrate having an island shape by introducing impurities of a second conductivity type;
a highly doped first conductivity type region formed inside said second conductivity type region by introducing impurities of the first conductivity type at high concentration;
a plurality of first trenches each extending from a surface of said highly doped first conductivity type region so as to reach at least said second conductivity type region on said first semiconductor substrate;
an insulation film formed on an inner wall surface of each of the first trenches;
an electrode portion made of polycrystalline silicon filled in each of the first trenches with said insulation film interposed therebetween;
a plurality of second trenches formed inside said second conductivity type region so that each of the second trenches is positioned between an adjacent pair of said first trenches in parallel with said first trenches; and
a second conductivity type protrusion region formed with a junction deeper than a junction of said second conductivity type region by introducing impurities of the second conductivity type through each of said second trenches by ion implantation. - View Dependent Claims (4, 5, 6, 7, 8, 9, 10)
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15. A method of manufacturing a semiconductor device comprising:
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forming a second conductivity type region in a semiconductor substrate having a principal surface of a first conductivity type by implanting impurities of a second conductivity type two or more times;
forming a first conductivity type region inside the island of said second conductivity type region, said first conductivity type region having a higher impurity concentration than said semiconductor substrate;
forming a trench in a depth direction of said semiconductor substrate by anisotropic etching;
forming a sacrificed oxide film on an inner wall surface of the trench by thermal oxidation;
removing said sacrificed oxide film;
forming an insulation film in an interior of said trench; and
filling said trench formed said insulation film with a polycrystalline silicon film. - View Dependent Claims (16, 17, 18, 19, 25, 27)
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20. A method of manufacturing a semiconductor device comprising:
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forming a second conductivity type region, in a semiconductor substrate having a principal surface of a first conductivity type;
forming a first conductivity type region inside said second conductivity type region, the first conductivity type region having a higher concentration than said semiconductor substrate;
forming a plurality of first trenches in a depth direction of said semiconductor substrate by anisotropic etching;
forming a sacrificed oxide film formed on an inner surface wall of each of the first trenches by thermal oxidation;
removing said sacrificed oxide film;
forming an insulation film in an interior of each of said first trenches;
filling each of the first trenches with a polycrystalline silicon film;
forming a plurality of second trenches in the second conductivity type region each positioned between an adjacent pair of said plurality of first trenches in parallel with said plurality of first trenches;
forming a second conductivity type protrusion region with a junction deeper than a junction of said second conductivity type region by introducing impurities of the second conductivity type from each of the second trenches by two or more ion implantation steps; and
forming a metal electrode so as to electrically connect said first conductivity type region with said second conductivity type protrusion region in each of the second trenches. - View Dependent Claims (21, 22, 23, 24, 26, 28)
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Specification