Insulated gate bipolar transistor having a reduced tail current and method of fabricating the same
AssigneeSanken Electric Co., Ltd.
InventorsKatsuyuki Torii, Ryoji Takahashi
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Abstract
An IGBT has an N-type buffer region between a P-type collector region and a P-type base region. The buffer region includes arsenic as a N-type impurity. The buffer region is formed to have a relatively high impurity concentration of equal to or greater than 5×1017 cm-3 and a relatively small thickness of 2 to 10 μm.
Claims6
An insulated gate bipolar transistor comprising:
- a P-type collector region;
- an N-type buffer region which is formed on said P-type collector region;
- an N-type base region which is formed on said N-type buffer region and has an impurity concentration lower than that of said N-type buffer region;
- a P-type base region which is formed in a surface region of said N-type base region;
- and
- an N-type emitter region which is formed in a surface region of said P-type base region,
- wherein said N-type buffer region includes arsenic as an N-type impurity at an impurity concentration of equal to or greater than 5×17 cm−3, and has a thickness of 2 μm to 10 μm, and
- wherein an impurity concentration of the N-type impurity in said N-type buffer region is higher than an impurity concentration of a P-type impurity in said P-type collector region.
A method of fabricating an insulated gate bipolar transistor having a P-type collector region, an N-type buffer region which is formed on said P-type collector region, an N-type base region which is formed on said N-type buffer region and has an impurity concentration lower than that of said N-type buffer region, a P-type base region which is formed in a surface region of said N-type base region, and an N-type emitter region which is formed in a surface region of said P-type base region,
- wherein said N-type buffer region is formed by diffusing arsenic, as an N-type impurity, at an impurity concentration of equal to or greater than 5×1017 cm−3, and in such a way that said region has a thickness of 2 μm to 10 μm.
- wherein an impurity concentration of the N-type impurity in said N-type buffer region is made higher than an impurity concentration of a P-type impurity in said P-type collector region.
Dependencies are inferred from the claim text.