Integrated circuits and devices with interleaved transistor elements, and methods of their fabrication
A monolithic integrated circuit includes first and second pluralities of parallel-connected transistor elements (e.g., transistor fingers). To spread heat in the IC, the first and second pluralities of transistor elements are interleaved with each other and arranged in a first row. The IC also may include third and fourth pluralities of parallel-connected transistor elements arranged in a second row. The transistor elements in the first row may be series and shunt transistors of an RF switch transmit path, and the transistor elements in the second row may be series and shunt transistors of an RF switch receive path. During a transmit mode of operation, the series transistors in the transmit path and the shunt transistors in the receive path are closed. During a receive mode of operation, the shunt transistors in the transmit path and the series transistors in the receive path are closed.
1. A monolithic integrated circuit comprising:
a semiconductor substrate with a first surface and a second surface;
a first node;
a second node;
a third node;
a first plurality of parallel-connected first transistor elements proximate to the first surface, wherein each of the first transistor elements includes a first current carrying terminal connected to the first node, and a second current carrying terminal connected to the second node; and
a second plurality of parallel-connected second transistor elements proximate to the first surface, wherein each of the second transistor elements includes a first current carrying terminal connected to the first node, and a second current carrying terminal connected to the third node, and wherein the first plurality of transistor elements is interleaved with the second plurality of transistor elements.
2. The integrated circuit of claim 1 , wherein each of the parallel-connected transistor elements is a transistor finger, which includes the first current carrying terminal, the second current carrying terminal, and a control terminal.
3. The integrated circuit of claim 1 , wherein:
the first node includes a first conductive pad proximate to the first surface of the semiconductor substrate;
the second node includes a second conductive pad proximate to the first surface of the semiconductor substrate; and
the third node includes a through substrate via that is electrically coupled between the second current carrying terminals of the second transistor elements and the second surface of the semiconductor substrate.
4. The integrated circuit of claim 1 , wherein the first and second pluralities of parallel-connected transistor elements are interleaved with a 1:1 interleaving pattern.
5. The integrated circuit of claim 1 , wherein the first and second pluralities of parallel-connected transistor elements are interleaved with a N:M:multiple interleaving pattern, where N and M are both integers greater than 1.
6. The integrated circuit of claim 1 , wherein the first and second pluralities of parallel-connected transistor elements are interleaved with a N:1 interleaving pattern, where N is an integer greater than 1.
7. The integrated circuit of claim 1 , wherein the first and second pluralities of parallel-connected transistor elements are arranged in a first row of transistor elements, and wherein the integrated circuit further comprises:
a second row of transistor elements that includes
a third plurality of parallel-connected transistor elements proximate to the first surface, and
a fourth plurality of parallel-connected transistor elements proximate to the first surface.
8. The integrated circuit of claim 7 , wherein:
first current carrying terminals of the third plurality of parallel-connected transistor elements are coupled to the second node;
first current carrying terminals of the fourth plurality of parallel-connected transistor elements are coupled to the third node;
second current carrying terminals of the third plurality of parallel-connected transistor elements are coupled to a fourth node; and
second current carrying terminals of the fourth plurality of parallel-connected transistor elements are coupled to the fourth node.
9. The integrated circuit of claim 7 , wherein the third plurality of transistor elements are interleaved with the fourth plurality of transistor elements.
10. The integrated circuit of claim 1 , wherein:
each of the transistor elements of the first plurality of transistor elements is a relatively high-power dissipating series transistor element; and
each of the transistor elements of the second plurality of transistor elements is a relatively low-power dissipating shunt transistor element.
11. A radio frequency (RF) switch comprising:
a semiconductor substrate with a first surface and a second surface;
a plurality of first series transistor elements proximate to the first surface, wherein each of the first series transistor elements has a channel that is electrically coupled between a first node and an antenna node; and
a plurality of first shunt transistor elements proximate to the first surface, wherein each of the first shunt transistor elements has a channel that is electrically coupled between the first node and a ground node, and the plurality of first series transistor elements is interleaved with the plurality of first shunt transistor elements in a first row.
12. The RF switch of claim 11 , further comprising:
a controller configured to provide control signals to control terminals of the first series transistor elements and the first shunt transistor elements so that, at any given time, either the first series transistor elements or the first shunt transistor elements, but not both, are in a conducting state.
13. The RF switch of claim 11 , wherein the first node is a transmit signal input node, and the RF switch further comprises:
a plurality of second series transistor elements proximate to the first surface, wherein each of the second series transistor elements has a channel that is electrically coupled between the antenna node and a receive signal output node; and
a plurality of second shunt transistor elements proximate to the first surface, wherein each of the second shunt transistor elements has a channel that is electrically coupled between the receive signal output node and the ground node.
14. The RF switch of claim 13 , further comprising:
a controller configured to provide control signals to control terminals of the first series transistor elements, the first shunt transistor elements, the second series transistor elements, and the second shunt transistor elements so that,
during a transmit mode of operation, the first series transistor elements and the second shunt transistor elements are in a conducting state, and the second series transistor elements and the first shunt transistor elements are in a non-conducting state, and
during a receive mode of operation, the second series transistor elements and the first shunt transistor elements are in a conducting state, and the first series transistor elements and the second shunt transistor elements are in a non-conducting state.
15. The RF switch of claim 13 , wherein the plurality of second series transistor elements is interleaved with the plurality of second shunt transistor elements in a second row.