High-voltage vertical transistor with a multi-layered extended drain structure
First Claim
1. A vertical high-voltage transistor comprising:
- a drain region of a first conductivity type;
at least one source region of the first conductivity type;
at least one body region of a second conductivity type opposite to the first conductivity type, the at least one body region adjoining the source region;
a plurality of drift regions of the first conductivity type arranged in parallel and extending in a first direction from the drain region to the at least one body region, adjacent ones of the drift regions being separated in a second direction orthogonal to the first direction by a dielectric layer;
at least one field plate member disposed within the dielectric layer, the at least one field plate member being fully insulated from the drift regions; and
an insulated gate disposed between the at least one field plate member and the at least one body region, the insulated gate intersecting a line that extends in the second direction from the at least one field plate member to the at least one body region, with a channel region being defined in the at least one body region adjacent the insulated gate between the at least one source region and at least one of the drift regions.
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Accused Products
Abstract
A high-voltage transistor with a low specific on-state resistance and that supports high voltage in the off-state includes one or more source regions disposed adjacent to a multi-layered extended drain structure which comprises extended drift regions separated from field plate members by one or more dielectric layers. With the field plate members at the lowest circuit potential, the transistor supports high voltages applied to the drain in the off-state. The layered structure may be fabricated in a variety of orientations. A MOSFET structure may be incorporated into the device adjacent to the source region, or, alternatively, the MOSFET structure may be omitted to produce a high-voltage transistor structure having a stand-alone drift region.
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Citations
25 Claims
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1. A vertical high-voltage transistor comprising:
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a drain region of a first conductivity type;
at least one source region of the first conductivity type;
at least one body region of a second conductivity type opposite to the first conductivity type, the at least one body region adjoining the source region;
a plurality of drift regions of the first conductivity type arranged in parallel and extending in a first direction from the drain region to the at least one body region, adjacent ones of the drift regions being separated in a second direction orthogonal to the first direction by a dielectric layer;
at least one field plate member disposed within the dielectric layer, the at least one field plate member being fully insulated from the drift regions; and
an insulated gate disposed between the at least one field plate member and the at least one body region, the insulated gate intersecting a line that extends in the second direction from the at least one field plate member to the at least one body region, with a channel region being defined in the at least one body region adjacent the insulated gate between the at least one source region and at least one of the drift regions. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14)
a source electrode electrically connected to the at least one source region; and
a drain electrode electrically connected to the drain region.
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3. The vertical high-voltage transistor according to claim 1 wherein the high-voltage transistor is fabricated on a semiconductor substrate having a planar bottom surface, the first direction being oriented perpendicular to the planar bottom surface and the second direction being oriented parallel to the planar bottom surface.
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4. The vertical high-voltage transistor according to claim 1 wherein the first conductivity type comprises n-type and the second conductivity type comprises p-type.
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5. The vertical high-voltage transistor according to claim 1 wherein the first conductivity type comprises p-type and the second conductivity type comprises n-type.
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6. The vertical high-voltage transistor according to claim 1 wherein the drift regions have a length oriented in the first direction and a width oriented in the second direction, the length being more than five times the width.
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7. The vertical high-voltage transistor according to claim 1 wherein the channel region is oriented parallel to the first direction.
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8. The vertical high-voltage transistor according to claim 1 wherein the at least one field plate member comprises heavily doped polysilicon.
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9. The vertical high-voltage transistor according to claim 7 wherein at least one field plate member has a length in the first direction and is oriented substantially parallel to the drift regions.
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10. The vertical high-voltage transistor according to claim 1 wherein the dielectric layer comprises silicon dioxide.
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11. The vertical high-voltage transistor according to claim 1 wherein the drift regions have a doping that is higher near the drain region and lower near the at least one body region.
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12. The vertical high-voltage transistor according to claim 1 wherein the drift regions each have a linearly graded doping profile.
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13. The vertical high-voltage transistor according to claim 1 wherein each of the drift regions has a width in the second direction that is less than or equal to a distance in the second direction that separates each of the drift regions from the at least one field plate member.
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14. The vertical high-voltage transistor according to claim 1 wherein the at least one field plate member extends in the first direction beyond the insulated gate.
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15. A vertical high-voltage transistor comprising:
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a drain region of a first conductivity type;
at least one source region of the first conductivity type;
at least one body region of a second conductivity type opposite to the first conductivity type, the at least one body region adjoining the source region;
a plurality of drift regions of the first conductivity type arranged in parallel and extending in a first direction from the drain region to the at least one body region, adjacent ones of the drift regions being separated in a second direction orthogonal to the first direction by a dielectric layer;
at least one field plate member disposed within the dielectric layer, the at least one field plate member being fully from the drift regions; and
an insulated gate disposed between the at least one field plate member and the at least one body region along a line that extends in the second direction, a top portion of the at least one field plate member extending above a lowermost portion of the insulated gate. - View Dependent Claims (16, 17, 18, 19, 20, 21, 22, 23, 24, 25)
a source electrode electrically connected to the at least one source region; and
a drain electrode electrically connected to the drain region.
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17. The vertical high-voltage transistor according to claim 15, wherein the high-voltage transistor is fabricated on a semiconductor substrate having a planar bottom surface, the first direction being oriented perpendicular to the planar bottom surface and the second direction being oriented parallel to the planar bottom surface.
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18. The vertical high-voltage transistor according to claim 15 wherein the first conductivity type comprises n-type and the second conductivity type comprises p-type.
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19. The vertical high-voltage transistor according to claim 15 wherein the first conductivity type comprises p-type and the second conductivity type comprises n-type.
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20. The vertical high-voltage transistor according to claim 15 wherein the drift regions have a length oriented in the first direction and a width oriented in the second direction, the length being more than five times the width.
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21. The vertical high-voltage transistor according to claim 15 wherein the at least one field plate member comprises heavily doped polysilicon.
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22. The vertical high-voltage transistor according to claim 15 wherein the dielectric layer comprises silicon dioxide.
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23. The vertical high-voltage transistor according to claim 15 wherein the drift regions have a doping that is higher near the drain region and lower near the at least one body region.
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24. The vertical high-voltage transistor according to claim 15 wherein the drift regions each have a linearly graded doping profile.
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25. The vertical high-voltage transistor according to claim 15 wherein each of the drift regions has a width in the second direction that is less than or equal to a distance in the second direction that separates each of the drift regions from the at least one field plate member.
Specification