Insulated gate bipolar transistor
AssigneeFuji Electric Co., Ltd.
InventorNoriyuki Iwamuro
Life of this patent
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Abstract
An insulated gate bipolar transistor employs a semiconductor substrate constructed by putting a high impurity density area, a low impurity density and a conductivity modulation area, respectively, of an n type on one another sequentially on a substrate of a p type, serving as a drain area. A gate is disposed on a gate oxide film deposited on the conductivity modulation area. A channel forming layer of a p type and a source layer of an n type are diffused from windows of the gate in such a manner that the peripheral edges of these layers creep under the gate, and a drain terminal, a source terminal, and on/off controlling gate terminal extend from the drain area, the channel forming layer and source layer, and the gate, respectively.
Claims5
An IGBT, comprising:
- a semi-conductor substrate having first and second opposite surfaces;
- said substrate including:
- a drain area of one conductivity type adjacent the first opposite surface;
- a high impurity density area of another conductivity type disposed on the drain area of the semiconductor substrate;
- a low impurity density area having an impurity density lower than the high impurity density area of the other conductivity type disposed on the high impurity density area;
- a conductivity modulation area of the other conductivity type having a selected impurity density and thickness disposed between the second opposite surface and the low impurity density area, the low impurity density area having a thickness in a range of 20.about.50% of the sum of the thickness of said low impurity density area and the thickness of said conductivity modulation;
- an insulation film disposed on the conductivity modulation area;
- a gate disposed on said insulation film overlying the conductivity modulation area;
- the semiconductor substrate including a channel forming layer of the one conductivity type disposed in the conductivity modulation area adjacent the second opposite surface with edge portions extending beneath an edge of the gate;
- a source layer of said other conductivity type diffused in the channel forming layer extending beneath the channel forming layer defining a window beneath a central portion of the gate;
- a drain terminal connected to and extending from the drain area;
- a source terminal connected to and extending from the source layer;
- and
- a gate terminal connected to and extending from the gate.
Dependencies are inferred from the claim text.