Lateral conductivity modulated mosfet

Claim 2

A lateral conductivity modulated MOSFET, comprising: a semiconductor layer of a first conductivity type; a first-conductivity type base layer selectively formed in a surface region of said semiconductor layer; a second-conductivity type source layer selectively formed in a surface region of said first-conductivity type base layer; a second-conductivity type base layer selectively formed in said semiconductor layer; a first-conductivity type drain layer formed in a surface region of said second-conductivity type base layer; a gate insulation film formed on that surface portion of the first-conductivity type base layer which is sandwiched between said source layer and said second-conductivity type base layer; a gate electrode formed on said gate insulation film; a source electrode in contact with both said source layer and said first-conductivity type base layer; a drain electrode in contact with said drain layer; a second-conductivity type cathode layer formed in a surface region of said semiconductor layer in such a manner that said second-conductivity type cathode layer is located adjacent to said second-conductivity type base layer and separated from said second-conductivity type base layer; and a cathode electrode in contact with said cathode layer, said cathode electrode being kept at the same potential level as that of said drain electrode.

Claim 3

A conductivity modulated MOSFET according to claim 1, wherein an insulation film is formed in such a manner as to extend between the surface of said drain layer and the surface of said cathode layer, said drain electrode and said cathode electrode being integral with each other and formed on said insulation film.

Claim 4

A conductivity modulated MOSFET according to claim 1, wherein said semiconductor layer is formed above a semiconductor substrate and isolated by a dielectric from said semiconductor substrate.

Claim 5

A conductivity modulated MOSFET according to claim 1, wherein said gate electrode is in the form of a first ring disposed above an upper surface of said semiconductor layer, said source layer is located at an outer periphery of a projection of the first ring onto said semiconductor layer, said drain layer is in the form of a second ring and is located inside of said projection of the first ring, and said cathode layer is located inside of said drain layer.

Claim 6

A conductivity modulated MOSFET according to claim 1, wherein said gate electrode is in the form of a first ring disposed above an upper surface of said semiconductor layer, said source layer is located at an inner periphery of a projection of the first ring onto said semiconductor layer, said drain layer is located outside of said projection of the first ring, and said cathode layer is located outside of said drain layer.

Claim 7

A lateral conductivity modulated MOSFET, comprising: a semiconductor layer of a first conductivity type; a first-conductivity type base layer selectively formed in a surface region of said semiconductor layer; a second-conductivity type source layer selectively formed in a surface region of said first-conductivity type base layer; a second-conductivity type base layer selectively formed in said semiconductor layer; a first-conductivity type drain layer formed in a surface region of said second-conductivity type base layer; a first gate insulation film formed on that surface portion of the first-conductivity type base layer which is sandwiched between said source layer and said second-conductivity type base layer; a first gate electrode formed on said first gate insulation film; a source electrode in contact with both said source layer and said first-conductivity type base layer; a drain electrode in contact with said drain layer; a second-conductivity type cathode layer formed in a surface region of said semiconductor layer in such a manner that said second-conductivity type cathode layer is located adjacent to said second-conductivity type base layer and separated from said second-conductivity type base layer; a cathode electrode in contact with said cathode layer, said cathode electrode being kept at the same potential level as that of said drain electrode; a second gate insulation film formed on that surface portion of the second-conductivity type base layer which is sandwiched between said drain layer and said cathode layer; and a second gate electrode formed on said second gate insulation film.

Claim 8

A lateral conductivity modulated MOSFET, comprising: a semiconductor layer of a first conductivity type; a first-conductivity type base layer selectively formed in a surface region of said semiconductor layer; a second-conductivity type source layer selectively formed in a surface region of said first-conductivity type base layer; a second-conductivity type base layer selectively formed in said semiconductor layer; a first-conductivity type drain layer formed in a surface region of said second-conductivity type base layer; a first gate insulation film formed on that surface portion of the first-conductivity type base layer which is sandwiched between said source layer and said second-conductivity type base layer; a first gate electrode formed on said first gate insulation film; a source electrode in contact with both said source layer and said first-conductivity type base layer; a drain electrode in contact with said drain layer; a second-conductivity type cathode layer formed in a surface region of said semiconductor layer in such a manner that said second-conductivity type cathode layer is located adjacent to said second-conductivity type base layer and separated from said second-conductivity type base layer; a cathode electrode in contact with said cathode layer, said cathode electrode being kept at the same potential level as that of said drain electrode; a second gate insulation film formed on that surface portion of the second-conductivity type base layer which is sandwiched between said drain layer and said cathode layer; and a second gate electrode formed on said second gate insulation film.

Claim 9

A conductivity modulated MOSFET according to claim 6, wherein an insulation film is formed on the surface of said second gate electrode, said drain electrode and said cathode electrode being integral with each other and formed on said insulation film.

Claim 10

A conductivity modulated MOSFET according to claim 6, wherein said semiconductor layer is formed above a semiconductor substrate and isolated by a dielectric from said semiconductor substrate.

Claim 11

A conductivity modulated MOSFET according to claim 6, wherein said first gate electrode is in the form of a first ring disposed above said semiconductor layer, said source layer is located at an outer periphery of a projection of the first ring onto said semiconductor layer, said drain layer is in the form of a second ring and is located inside of said projection of the first ring, and said cathode layer is located inside of said drain layer.

Claim 12

A conductivity modulated MOSFET according to claim 9, wherein said second gate electrode is formed between said drain layer and said cathode layer.

Claim 13

A conductivity modulated MOSFET according to claim 6, wherein said first gate electrode is in the form of a first ring disposed above said semiconductor layer, said source layer is located at an inner periphery of a projection of the first ring onto said semiconductor layer, said drain layer is located outside of said projection of the first ring, and said cathode layer is located outside of said drain layer.

Claim 14

A conductivity modulated MOSFET according to claim 11, wherein an insulation film is formed on the surface of said second gate electrode, said drain electrode and said cathode electrode being integral with each other and formed on said insulation film.

Claim 15

A lateral conductivity modulated MOSFET, comprising: a semiconductor layer of a first conductivity type; a first-conductivity type base layer selectively formed in a surface region of said semiconductor layer; a second-conductivity type source layer selectively formed in a surface region of said first-conductivity type base layer; a second-conductivity type base layer selectively formed in said semiconductor layer; a first-conductivity type drain layer formed in a surface region of said second-conductivity type base layer; a first gate insulation film formed on that surface portion of the first-conductivity type base layer which is sandwiched between said source layer and said second-conductivity type base layer; a first gate electrode formed on said first gate insulation film; a source electrode in contact with both said source layer and said first-conductivity type base layer; a drain electrode in contact with both said drain layer and said second-conductivity type base layer; a second gate insulation film formed on that surface portion of the second-conductivity type base layer which is sandwiched between said drain layer and a semiconductor layer portion located adjacent to said drain layer; and a second gate electrode formed on said second gate insulation film.

Claim 16

A lateral conductivity modulated MOSFET, comprising: a semiconductor layer of a first conductivity type; a first-conductivity type base layer selectively formed in a surface region of said semiconductor layer; a second-conductivity type source layer selectively formed in a surface region of said first-conductivity type base layer; a second-conductivity type base layer selectively formed in said semiconductor layer; a first-conductivity type drain layer formed in a surface region of said second-conductivity type base layer; a first gate insulation film formed on that surface portion of the first-conductivity type base layer which is sandwiched between said source layer and said second-conductivity type base layer; a first gate electrode formed on said first gate insulation film; a source electrode in contact with both said source layer and said first-conductivity type base layer; a drain electrode in contact with both said drain layer and said second-conductivity type base layer; a second gate insulation film formed on that surface portion of the second-conductivity type base layer which is sandwiched between said drain layer and a semiconductor layer portion located adjacent to said drain layer; and a second gate electrode formed on said second gate insulation film.

Claim 17

A conductivity modulated MOSFET according to claim 13, wherein said semiconductor layer is formed above a semiconductor substrate and isolated by a dielectric from said semiconductor substrate.

Claim 18

A lateral conductivity modulated MOSFET, comprising: a semiconductor layer of a first conductivity type; a first-conductivity type base layer selectively formed in a surface region of said semiconductor layer; a second-conductivity type source layer selectively formed in a surface region of said first-conductivity type base layer; a second-conductivity type base layer selectively formed in said semiconductor layer; a first-conductivity type drain layer formed in a surface region of said second-conductivity type base layer; a first gate insulation film formed on that surface portion of the first-conductivity type base layer which is sandwiched between said source layer and said second-conductivity type base layer; a first gate electrode formed on said first gate insulation film; a source electrode in contact with both said source layer and said first-conductivity type base layer; a drain electrode in contact with both said drain layer and said second-conductivity type base layer; a second-conductivity type cathode layer formed in a surface region of said semiconductor layer in such a manner that said second-conductivity type cathode layer is located adjacent to said second-conductivity type base layer and separated from said second-conductivity type base layer; a cathode electrode in contact with said cathode layer, said cathode electrode being kept at the same potential level as that of said drain electrode; a second gate insulation film formed on that surface portion of the second-conductivity type base layer which is sandwiched between said drain layer and said cathode layer; and a second gate electrode formed on said second gate insulation film.

Claim 19

A lateral conductivity modulated MOSFET, comprising: a semiconductor layer of a first conductivity type; a first-conductivity type base layer selectively formed in a surface region of said semiconductor layer; a second-conductivity type source layer selectively formed in a surface region of said first-conductivity type base layer; a second-conductivity type base layer selectively formed in said semiconductor layer; a first-conductivity type drain layer formed in a surface region of said second-conductivity type base layer; a first gate insulation film formed on that surface portion of the first-conductivity type base layer which is sandwiched between said source layer and said second-conductivity type base layer; a first gate electrode formed on said first gate insulation film; a source electrode in contact with both said source layer and said first-conductivity type base layer; a drain electrode in contact with both said drain layer and said second-conductivity type base layer; a second-conductivity type cathode layer formed in a surface region of said semiconductor layer in such a manner that said second-conductivity type cathode layer is located adjacent to said second-conductivity type base layer and separated from said second-conductivity type base layer; a cathode electrode in contact with said cathode layer, said cathode electrode being kept at the same potential level as that of said drain electrode; a second gate insulation film formed on that surface portion of the second-conductivity type base layer which is sandwiched between said drain layer and said cathode layer; and a second gate electrode formed on said second gate insulation film.

Claim 20

A conductivity modulated MOSFET according to claim 15, wherein an insulation film is formed on said second gate electrode, said drain electrode and said cathode electrode being integral with each other and formed on said insulation film.

Claim 21

A conductivity modulated MOSFET according to claim 15, wherein said semiconductor layer is formed above a semiconductor substrate and isolated by a dielectric from said semiconductor substrate.

Claim 22

A conductivity modulated MOSFET according to claim 15, wherein said first gate electrode is in the form of a first ring disposed above said semiconductor layer, said source layer is located at an outer periphery of a projection of the first ring onto said semiconductor layer, said drain layer is in the form of a second ring and is located inside of said projection of the first ring, and said cathode layer is located inside of said drain layer.

Claim 23

A conductivity modulated MOSFET according to claim 18, wherein said second gate electrode is formed between said drain layer and said cathode layer.

Claim 24

A conductivity modulated MOSFET according to claim 15, wherein said first gate electrode is in the form of a first ring disposed above said semiconductor layer, said source layer is located at a inner periphery of a projection of the first ring onto said semiconductor layer, said drain layer is located outside of said projection of the first ring, and said cathode layer is located outside of said drain layer.

Claim 25

A conductivity modulated MOSFET according to claim 20, wherein a third insulation film is formed over the surface of said second gate electrode, said drain electrode and said cathode electrode being integral with each other and formed over said third insulation film.