Semiconductor device having high breakdown voltage and method of manufacturing the same
First Claim
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1. A semiconductor device comprising an insulated gate bipolar transistor of a gate trench type having a high breakdown voltage comprising:
- a semiconductor substrate of a first conductivity type having first and second main surfaces;
gate trenches, each having a first groove formed at a predetermined region of said first main surface and extending from said first main surface into said semiconductor substrate to a depthwise direction, a gate insulating film covering an inner surface of said first groove, and an electrode filling said first groove and made of an electrical conductor;
an impurity region of the first conductivity type formed near said first main surface and located in the vicinity of said gate trench;
a first main electrode layer covering said first main surface, opposed to said gate trench with an insulating film therebetween and electrically connected to said impurity regions and said semiconductor substrate;
a second impurity layer of the second conductivity type formed at said second main surface; and
a second main electrode layer formed at a surface of said second impurity layer, wherein each gate trench is spaced from another gate trench with a predetermined pitch, and a plurality of emitter trenches, not gate trenches, arranged between two gate trenches, each emitter trench having a second groove extending from said first main surface into said semiconductor substrate in a depthwise direction, an insulating film covering an inner surface of said second groove and second electrode filling said second groove are arranged at positions between said gate trenches, wherein a surface of the impurity region of the first conductivity type formed near the main surface exposed between emitter trenches is covered with an interlayer insulating film.
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Abstract
In a semiconductor device with a high breakdown voltage, insulating layers are buried at regions in n- silicon substrate located between gate trenches which are arranged with a predetermined pitch. This structure increases a carrier density at a portion near an emitter, and improves characteristic of an IGBT of a gate trench type having a high breakdown voltage.
39 Citations
4 Claims
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1. A semiconductor device comprising an insulated gate bipolar transistor of a gate trench type having a high breakdown voltage comprising:
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a semiconductor substrate of a first conductivity type having first and second main surfaces; gate trenches, each having a first groove formed at a predetermined region of said first main surface and extending from said first main surface into said semiconductor substrate to a depthwise direction, a gate insulating film covering an inner surface of said first groove, and an electrode filling said first groove and made of an electrical conductor; an impurity region of the first conductivity type formed near said first main surface and located in the vicinity of said gate trench; a first main electrode layer covering said first main surface, opposed to said gate trench with an insulating film therebetween and electrically connected to said impurity regions and said semiconductor substrate; a second impurity layer of the second conductivity type formed at said second main surface; and a second main electrode layer formed at a surface of said second impurity layer, wherein each gate trench is spaced from another gate trench with a predetermined pitch, and a plurality of emitter trenches, not gate trenches, arranged between two gate trenches, each emitter trench having a second groove extending from said first main surface into said semiconductor substrate in a depthwise direction, an insulating film covering an inner surface of said second groove and second electrode filling said second groove are arranged at positions between said gate trenches, wherein a surface of the impurity region of the first conductivity type formed near the main surface exposed between emitter trenches is covered with an interlayer insulating film. - View Dependent Claims (2, 3)
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4. A semiconductor device comprising an insulated gate bipolar transistor of a gate trench type having a high breakdown voltage comprising:
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a semiconductor substrate of a first conductivity type having first and second main surfaces; gate trenches, each having a first groove formed at a predetermined region of said first main surface and extending from said first main surface into said semiconductor substrate to a depthwise direction, a gate insulating film covering an inner surface of said first groove, and an electrode filling said first groove and made of an electrical conductor; an impurity region of the first conductivity type formed near said first main surface and located in the vicinity of said gate trench; a first main electrode layer covering said first;
main surface, opposed to said gate trench with an insulating film therebetween and electrically connected to said impurity regions and said semiconductor substrate;a second impurity layer of the second conductivity type formed at said second main surface; and a second main electrode layer formed at a surface of said second impurity layer, wherein each gate trench is spaced from another gate trench with a predetermined pitch, and a plurality of emitter trenches, not gate trenches, arranged between two gate trenches, each emitter trench having a second groove extending from said first main surface into said semiconductor substrate in a depthwise direction, an insulating film covering an inner surface of said second groove and second electrode filling said second groove are arranged at positions between said gate trenches, wherein a distance between a side wall of said emitter trench and a side wall of said gate trench is equal to or smaller than one-tenth of the pitch of said gate trenches.
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Specification