Lateral DMOS device with dummy gate
First Claim
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1. An integrated circuit device comprising:
- a source region having a first conductivity type;
a drain region having the first conductivity type;
an interposed region between the source region and the drain region;
a first gate dielectric over the interposed region;
an active gate over the first gate dielectric, an entirety of the active gate being on the first gate dielectric;
a second gate dielectric over the interposed region, the second gate dielectric being in direct contact with the first gate dielectric such that an upper surface of the first gate dielectric and an upper surface of the second gate dielectric form a step, wherein the second gate dielectric is thicker than the first gate dielectric, wherein a lower surface of the first gate dielectric is not planar with a lower surface of the second gate dielectric; and
a dummy gate over the second gate dielectric, wherein the dummy gate is interposed between the active gate and the drain region, an entirety of the dummy gate being on the second gate dielectric, wherein the step is free of the active gate and the dummy gate.
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Abstract
An LDMOS transistor with a dummy gate comprises an extended drift region over a substrate, a drain region in the extended drift region, a channel region in the extended drift region, a source region in the channel region, a first dielectric layer with a first thickness formed over the extended drift region, a second dielectric layer with a second thickness formed over the extended drift region and the channel region, wherein the first thickness is greater than the second thickness, and wherein the first dielectric layer and the second dielectric layer form two steps, a first gate formed over the first dielectric layer and a second gate formed above the second dielectric layer.
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Citations
20 Claims
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1. An integrated circuit device comprising:
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a source region having a first conductivity type; a drain region having the first conductivity type; an interposed region between the source region and the drain region; a first gate dielectric over the interposed region; an active gate over the first gate dielectric, an entirety of the active gate being on the first gate dielectric; a second gate dielectric over the interposed region, the second gate dielectric being in direct contact with the first gate dielectric such that an upper surface of the first gate dielectric and an upper surface of the second gate dielectric form a step, wherein the second gate dielectric is thicker than the first gate dielectric, wherein a lower surface of the first gate dielectric is not planar with a lower surface of the second gate dielectric; and a dummy gate over the second gate dielectric, wherein the dummy gate is interposed between the active gate and the drain region, an entirety of the dummy gate being on the second gate dielectric, wherein the step is free of the active gate and the dummy gate. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8)
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9. An integrated circuit device comprising:
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a source region having a first conductivity type; a drain region having the first conductivity type; a first doped region having a second conductivity type, the first doped region being interposed between the source region and the drain region; a drift region having the first conductivity type, the drift region being interposed between the first doped region and the drain region; a first gate dielectric over the first doped region; an active gate over the first gate dielectric, an entirety of the first gate dielectric under the active gate having a first uniform thickness; a second gate dielectric over the drift region, wherein the second gate dielectric is thicker than the first gate dielectric, wherein a step is formed at an interface between the first gate dielectric and the second gate dielectric; and a dummy gate over the second gate dielectric, an entirety of the second gate dielectric under the dummy gate having a second uniform thickness, wherein the step is free of the active gate and the dummy gate. - View Dependent Claims (10, 11, 12, 13, 14, 15)
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16. A transistor comprising:
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an extended drift region having a first conductivity type; a drain region above the extended drift region, wherein the drain region has the first conductivity type; a source region above the extended drift region, the source region having the first conductivity type; a doped region interposed between the source region and the extended drift region, the doped region having a second conductivity type; a first dielectric layer with a first thickness over the extended drift region; a second dielectric layer with a second thickness over the extended drift region, wherein an upper surface of the first dielectric layer and an upper surface of the second dielectric layer form a step; an active gate on the first dielectric layer, an entirety of the active gate being on the first dielectric layer; and a dummy gate on the second dielectric layer, wherein the active gate is spaced apart from the dummy gate and the step, wherein an entirety of the dummy gate being on the second dielectric layer, and wherein the dummy gate is spaced apart from the step. - View Dependent Claims (17, 18, 19, 20)
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Specification