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US 2012/0068310 A1Published application
Semiconductor device
AssigneeMitsubishi Electric Corporation
InventorHitoshi UEMURA
Life of this patent
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Abstract
A carrier is prevented from being stored in a guard ring region in a semiconductor device. The semiconductor device has an IGBT cell including a base region and an emitter region formed in an n− type drift layer, and a p type collector layer arranged under the drift layer with a buffer layer interposed therebetween. A guard ring region having a guard ring is arranged around the IGBT cell. A lower surface of the guard ring region has a mesa structure provided by removing the collector layer.
Claims16
A semiconductor device comprising:
- a first semiconductor layer having a first conductivity type;
- a second semiconductor layer arranged under said first semiconductor layer and having a second conductivity type;
- an IGBT cell having a base region and an emitter region formed in said first semiconductor layer, and a collector layer provided as said second semiconductor layer;
- and
- a guard ring region provided around a cell region having said IGBT cell, and having a guard ring formed in said first semiconductor layer, wherein
- said second semiconductor layer is removed from a lower part of said guard ring region.
3 more elements
A semiconductor device comprising:
- a first semiconductor layer having a first conductivity type;
- a second semiconductor layer arranged under said first semiconductor layer and having a second conductivity type;
- an IGBT cell having a base region and an emitter region formed in said first semiconductor layer, and a collector layer provided as said second semiconductor layer;
- and
- a guard ring region provided around a cell region having said IGBT cell, and having a guard ring formed in said first semiconductor layer, wherein
- said first semiconductor layer comprises:
- a drift layer;
- and
- a buffer layer having an impurity concentration higher than that of said drift layer, and interposed between said drift layer and said second semiconductor layer, and
- an impurity layer having said second conductivity type is formed on a bottom part of said drift layer in said guard ring region.
7 more elements
A semiconductor device comprising:
- a first semiconductor layer having a first conductivity type;
- a second semiconductor layer arranged under said first semiconductor layer and having said first conductivity type having an impurity concentration higher than that of said first semiconductor layer;
- a diode cell having an anode layer formed in said first semiconductor layer and having a second conductivity type, and a cathode layer provided as said second semiconductor layer;
- a cathode electrode arranged on a lower surface of said second semiconductor layer;
- and
- a guard ring region provided around a cell region having said diode cell, and having a guard ring formed in said first semiconductor layer, wherein
- said cathode electrode is removed from a lower part of said guard ring region.
4 more elements
A semiconductor device comprising:
- a first semiconductor layer having a first conductivity type;
- a second semiconductor layer arranged under said first semiconductor layer and having said first conductivity type having an impurity concentration higher than that of said first semiconductor layer;
- a diode cell having an anode layer formed in said first semiconductor layer and having a second conductivity type, and a cathode layer provided as said second semiconductor layer;
- a cathode electrode arranged on a lower surface of said second semiconductor layer;
- and
- a guard ring region provided around a cell region having said diode cell, and having a guard ring formed in said first semiconductor layer, wherein
- an impurity layer having said second conductivity type is formed on a bottom part of said first semiconductor layer in said guard ring region.
4 more elements
Dependencies are inferred from the claim text.