Lateral trench MISFET
First Claim
1. A lateral trench MISFET comprising:
- a semiconductor layer of a first conductivity type;
a trench formed in a surface layer of said semiconductor layer;
a drain region of the first conductivity type formed at a bottom of said trench;
a side wall insulation film formed on a side face of said trench;
a base region of a second conductivity type formed in a portion of said semiconductor layer separate from the trench;
a source region of the first conductivity type formed in a part of a surface layer of said base region, such that said base region forms an extension portion that extends between said semiconductor layer and said source region;
a gate electrode overlying said extension portion;
a gate insulation film provided between the gate electrode and said extension portion;
a source electrode connected to both said source region and said base region; and
a conductive material disposed in said trench.
3 Assignments
0 Petitions
Accused Products
Abstract
To provide a lateral MISFET that has a uniform and reliable gate insulation film, and exhibits low on-resistance and excellent balance between the breakdown voltage and on-resistance. The device of the invention has an n-type semiconductor substrate, in a part of the surface layer thereof is formed a trench. An n-drain region is formed in the bottom of the trench. A side wall oxide film is formed on the side face of the trench. The trench is filled with a conductive material, on which is formed a drain electrode. A p-base region and an n-source region are self-aligned on the portion of the substrate in which the trench is not formed. A MIS gate is disposed on the p-base region. Since the portion of the substrate along the side wall oxide film functions as a drain drift region, the unit cell dimension are greatly reduced, the on-resistance is reduced, and therefore the trade-off relation between the breakdown voltage and the on-resistance is improved.
78 Citations
21 Claims
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1. A lateral trench MISFET comprising:
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a semiconductor layer of a first conductivity type; a trench formed in a surface layer of said semiconductor layer; a drain region of the first conductivity type formed at a bottom of said trench; a side wall insulation film formed on a side face of said trench; a base region of a second conductivity type formed in a portion of said semiconductor layer separate from the trench; a source region of the first conductivity type formed in a part of a surface layer of said base region, such that said base region forms an extension portion that extends between said semiconductor layer and said source region; a gate electrode overlying said extension portion; a gate insulation film provided between the gate electrode and said extension portion; a source electrode connected to both said source region and said base region; and a conductive material disposed in said trench. - View Dependent Claims (2, 3, 4, 5)
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6. A lateral trench MISFET comprising:
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a semiconductor layer of a first conductivity type; a trench formed in a surface layer of said semiconductor layer; a drain region of the first conductivity type formed at a bottom of said trench; a side wall insulation film formed on a side face of said trench; a well region of the first conductivity type formed in a part of the surface layer of said semiconductor layer separate from the trench, said well region being more heavily doped than said semiconductor layer; a base region of a second conductivity type formed in a part of a surface layer of said well region; a source region of the first conductivity type formed in a surface layer of said base region, such that said base region forms an extension portion that extends between said well region and said source region; a gate electrode overlying said extension portion; a gate insulation film provided between the gate electrode and said extension portion; a source electrode connected to both said source region and said base region; and a conductive material disposed in said trench. - View Dependent Claims (7, 8, 9, 10)
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11. A lateral trench MISFET comprising:
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a semiconductor layer of a first conductivity type; a trench formed in a surface layer of said semiconductor layer; a drain drift region of a second conductivity type formed at a portion of said semiconductor layer facing said trench; a drain region of the second conductivity type formed at a bottom of said trench, said drain region being more heavily doped than said drain drift region; a side wall insulation film formed on a side face of said trench; a base region of the first conductivity type formed in a portion of said semiconductor layer separate from the trench; a source region of the second conductivity type formed in a part of a surface layer of said base region, such that said base region forms an extension portion that extends between said drain drift region and said source region; a gate electrode overlying the extension portion; a gate insulation film provided between the gate electrode and said extension portion a source electrode connected to both said source region and said base region; and a conductive material disposed in said trench. - View Dependent Claims (12, 13)
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14. A lateral trench MISFET comprising:
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a semiconductor layer of a first conductivity type; a trench formed in a surface layer of said semiconductor layer; a drain region of the first conductivity type formed at a bottom of said trench; a side wall insulation film formed on a side face of said trench; a base region of a second conductivity type formed at least in a part of the surface layer of said semiconductor layer separate from said trench; a source region of the first conductivity type formed in a part of a surface layer of said base region, said base region including a trench facing portion between said semiconductor layer and said source region; a gate electrode opposed to and facing the trench portion of said base region; a gate insulation film provided between said gate electrode and said trench facing portion; a source electrode connected to both said source region and said base region; and a conductive material disposed in said trench. - View Dependent Claims (15, 16)
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17. A lateral trench MISFET comprising:
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a semiconductor layer of a first conductivity type; a trench formed in a surface layer of said semiconductor layer; a drain region of the first conductivity formed at a bottom of said trench; a side wall insulation film formed on a side face of said trench; a well region of the first conductivity type formed at least in a part of the surface layer of said semiconductor layer separate from the trench, said well region being more heavily doped than said semiconductor layer; a base region of a second conductivity type formed in a part of a surface layer of said well region; a source region of the first conductivity type formed in a part of a surface layer of said base region, said base region including a trench facing portion that extends between said well region and said source region; a gate electrode opposed to and facing the trench facing portion of said base region; a gate insulation film provided between said gate electrode and said trench facing portion; a source electrode connected to both said source region and said base region; and a conductive material disposed in said trench, said conductive material being from said gate electrode. - View Dependent Claims (18, 19)
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20. A lateral trench MISFET comprising:
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a semiconductor layer of a first conductivity type; a trench formed in a surface layer of said semiconductor layer; a drain drift region of a second conductivity type formed in a portion of said semiconductor layer facing said trench; a drain region of the second conductivity type formed at a bottom of said trench, said drain region being more heavily doped than said drain drift region; a side wall insulation film formed on a side face of said trench; a base region of the first conductivity type formed at least in a part of the surface layer of said semiconductor layer separate from said trench; a source region of the second conductivity type formed in a part of a surface layer of said base region, said base region including a trench facing portion between said drain drift region and said source region; a gate electrode opposed to and facing the trench facing portion of said base region; a gate insulation film provided between said gate electrode and said trench portion; a source electrode connected to both said source region and said base region; and a conductive material disposed in said trench, said conductive material being insulated from said gate electrode. - View Dependent Claims (21)
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Specification