Body contact FET
A field-effect transistor (FET) and a radio-frequency module are provided comprising an active region comprising a source region, a drain region, a body region disposed between the source region and the drain region, a first body extension portion in contact with the body region, a second body extension portion in contact with the body region, and a body contact region in contact with the first extension portion and the second extension portion; and a gate disposed on a top surface of the body region. A die is also provided comprising two or more such FETs.
1 . A field-effect transistor comprising:
an active region comprising a source region, a drain region, a body region disposed between the source region and the drain region, a first body extension portion in contact with the body region, a second body extension portion in contact with the body region, and a body contact region in contact with the first body extension portion and the second body extension portion, the source region and the body contact region being in contact with each other, the body contact region having a first side in contact with the first body extension portion, a second side in contact with the second body extension portion, and a third side in contact with the source region, and the source region having a first side in contact with the first body extension portion, a second side in contact with the second body extension portion, and a third side in contact with the body region; and
a gate disposed on a top surface of the body region.
2 . The field-effect transistor of claim 1 wherein the field-effect transistor is a silicon on insulator field-effect transistor having an insulator layer beneath the active region and a substrate beneath the insulator layer.
3 . The field-effect transistor of claim 1 wherein the first body extension portion is unitary with the body region.
4 . The field-effect transistor of claim 1 wherein the second body extension portion is unitary with the body region.
5 . The field-effect transistor of claim 1 wherein the first body extension portion extends from the body region beneath the source region.
6 . The field-effect transistor of claim 5 wherein the first body extension portion further extends beneath the body contact region.
7 . The field-effect transistor of claim 1 wherein the second body extension portion extends from the body region through the source region.
8 . The field-effect transistor of claim 7 wherein the second body extension portion extends from the body region through the source region along an edge of the source region.
9 . The field-effect transistor of claim 7 wherein the second body extension portion extends from the body region through the source region along through a middle portion of the source region, such that the source region is disposed on both sides of the second body extension portion.
10 . The field-effect transistor of claim 1 wherein the gate extends over a top surface of the second body extension portion.
11 . The field-effect transistor of claim 1 wherein the field-effect transistor is an extended drain field-effect transistor, the active region having a drain extension region disposed between an upper portion of the body region and the drain region.
12 . The field-effect transistor of claim 1 wherein the active region comprises one or more notches adjacent to the gate.
13 . The field-effect transistor of claim 1 wherein:
the body region, the first body extension portion and the second body extension portion comprise a semiconductor having a relatively weak doping of a first type;
the body contact region has a relatively strong doping of the first type; and
the source region and the drain region have a doping of a second type.
14 . A die comprising a first and second field-effect transistor, the first and second field-effect transistor each comprising;
an active region comprising a source region, a drain region, a body region disposed between the source region and the drain region, a first body extension portion in contact with the body region, a second body extension portion in contact with the body region, and a body contact region in contact with the first body extension portion and the second body extension portion;
a third field-effect transistor and a fourth field-effect transistor, the first and second field-effect transistors sharing a first common body contact region and being disposed on either side of the first common body contact region, the third and fourth field-effect transistors sharing a second common body contact region and being disposed on either side of the second common body contact region, and the first, second, third and fourth field-effect transistors sharing a common second body extension portion; and
a gate disposed on a top surface of the body region.
15 . The die of claim 14 wherein the first and second field-effect transistors share a common body contact region.
16 . The die of claim 15 wherein the body region of the first field-effect transistor and the body region of the second field-effect transistor are disposed on opposite sides of the common body contact region.
17 . The die of claim 14 wherein the first and second field-effect transistors share a common second body extension portion.
18 . The die of claim 14 wherein the first, second, third and fourth field-effect transistors share a common gate.