Dual channel trench LDMOS transistors and BCD process with deep trench isolation
First Claim
1. A dual channel trench LDMOS transistor, comprising:
- a substrate of a first conductivity type;
a semiconductor layer of a second conductivity type formed on the substrate;
a first trench formed in the semiconductor layer, the first trench being filled with a trench dielectric, a trench gate being formed in the first trench and insulated from the sidewall of the first trench by a first gate dielectric layer;
a body region of the first conductivity type formed in the semiconductor layer adjacent the first trench;
a source region of the second conductivity type formed in the body region and adjacent the first trench;
a planar gate insulated from the semiconductor layer by a second gate dielectric layer and overlying the body region, the source region being formed aligned to a first edge of the planar gate; and
a drain region of the second conductivity type formed in the semiconductor layer, the drain region being spaced apart from the body region by a drain drift region,wherein the planar gate forms a lateral channel of the LDMOS transistor in the body region between the source region and the drain drift region, and the trench gate in the first trench forms a vertical channel of the LDMOS transistor in the body region along the sidewall of the first trench between the source region and the semiconductor layer.
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Abstract
A dual channel trench LDMOS transistor includes a substrate of a first conductivity type; a semiconductor layer of a second conductivity type formed on the substrate; a first trench formed in the semiconductor layer where a trench gate is formed in an upper portion of the first trench; a body region of the first conductivity type formed in the semiconductor layer adjacent the first trench; a source region of the second conductivity type formed in the body region and adjacent the first trench; a planar gate overlying the body region; a drain region of the second conductivity type spaced apart from the body region by a drain drift region. The planar gate forms a lateral channel in the body region, and the trench gate in the first trench forms a vertical channel in the body region of the LDMOS transistor.
31 Citations
24 Claims
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1. A dual channel trench LDMOS transistor, comprising:
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a substrate of a first conductivity type; a semiconductor layer of a second conductivity type formed on the substrate; a first trench formed in the semiconductor layer, the first trench being filled with a trench dielectric, a trench gate being formed in the first trench and insulated from the sidewall of the first trench by a first gate dielectric layer; a body region of the first conductivity type formed in the semiconductor layer adjacent the first trench; a source region of the second conductivity type formed in the body region and adjacent the first trench; a planar gate insulated from the semiconductor layer by a second gate dielectric layer and overlying the body region, the source region being formed aligned to a first edge of the planar gate; and a drain region of the second conductivity type formed in the semiconductor layer, the drain region being spaced apart from the body region by a drain drift region, wherein the planar gate forms a lateral channel of the LDMOS transistor in the body region between the source region and the drain drift region, and the trench gate in the first trench forms a vertical channel of the LDMOS transistor in the body region along the sidewall of the first trench between the source region and the semiconductor layer. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22)
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23. A method for forming a dual channel trench LDMOS comprising:
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providing a substrate of a first conductivity type; forming a semiconductor layer of a second conductivity type on the substrate; forming a first trench in the semiconductor layer, the first trench being filled with a trench dielectric; forming a trench gate in the first trench, the trench gate being insulated from the sidewall of the first trench by a first gate dielectric layer; forming a body region of the first conductivity type in the semiconductor layer adjacent the first trench; forming a source region of the second conductivity type in the body region and adjacent the first trench; forming a planar gate insulated from the semiconductor layer by a second gate dielectric layer and overlying the body region, the source region being formed aligned to a first edge of the planar gate; and forming a drain region of the second conductivity type in the semiconductor layer, the drain region being spaced apart from the body region by a drain drift region, wherein the planar gate forms a lateral channel of the LDMOS transistor in the body region between the source region and the drain drift region, and the trench gate in the first trench forms a vertical channel of the LDMOS transistor in the body region along the sidewall of the first trench between the source region and the semiconductor layer. - View Dependent Claims (24)
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Specification