High-Q integrated circuit inductor structure and methods
FET IC structures that enable formation of high-Q inductors in a “flipped” SOI IC structure made using a back-side access process, such as an single layer transfer (SLT) process. Essentially, the interconnect layer superstructure of an IC is split into two parts, a “lower” superstructure and an “upper” superstructure. In various embodiments, one or more low-resistance interconnect layers are fabricated within an upper superstructure formed after the application of a back-side access process, allowing fabrication of inductors in one or more low-resistance interconnect layer. A significant advantage of such IC structures is that the low-resistance interconnect layer or layers are relocated from being near the handle wafer of a conventional SLT IC to being spaced away from the handle wafer by intervening structures. Fabricating inductors in such spaced low-resistance interconnect layer or layers reduces electromagnetic coupling with the handle wafer and thus increases the Q factor of the inductors.
1. An integrated circuit structure having a first side originally formed on a substrate, and an opposite second side, the first side being attached to a handle wafer and the opposite second side including one or more low-resistance interconnect layers fabricated within an upper superstructure formed after the application of a back-side access process.
2. The invention of claim 1 , wherein the integrated circuit structure includes at least one field effect transistor.
3. The invention of claim 1 , wherein the integrated circuit structure includes at least one field effect transistor having a conductive aligned supplemental gate.
4. The invention of claim 1 , wherein the integrated circuit structure is fabricated using a silicon-on-insulator process.
5. The invention of claim 1 , wherein the handle wafer is principally silicon.
6. The invention of claim 1 , wherein the handle wafer is principally silicon having a bonding layer of silicon dioxide, and the integrated circuit structure is attached to the bonding layer.
7. The invention of claim 1 , wherein the handle wafer includes a low resistivity silicon wafer.
8. An integrated circuit structure attached to a handle wafer and including one or more low-resistance interconnect layers fabricated within an upper superstructure formed after the application of a back-side access process, further including at least one inductor fabricated as part of at least one of the one or more low-resistance interconnect layers of the upper superstructure.
9. The invention of claim 8 , wherein at least one inductor has a Q factor of at least about 16 at about 2.4 GHz.
10. The invention of claim 8 , wherein at least one inductor comprises a coil having at least a first port and a second port.
11. The invention of claim 8 , wherein the back-side access process includes a single layer transfer process.
12. The invention of claim 8 , wherein the integrated circuit structure includes at least one field effect transistor.
13. The invention of claim 8 , wherein the integrated circuit structure includes at least one field effect transistor having a conductive aligned supplemental gate.
14. The invention of claim 8 , wherein the integrated circuit structure is fabricated using a silicon-on-insulator process.
15. The invention of claim 8 , wherein the handle wafer is principally silicon.
16. The invention of claim 8 , wherein the handle wafer is principally silicon having a bonding layer of silicon dioxide, and the integrated circuit structure is attached to the bonding layer.
17. The invention of claim 8 , wherein the handle wafer includes a low resistivity silicon wafer.
18. An integrated circuit structure attached to a handle wafer and including one or more low-resistance interconnect layers fabricated within an upper superstructure formed after the application of a back-side access process, further including at least one inductor fabricated as part of a first one of the one or more low-resistance interconnect layers of the upper superstructure, and at least one inductor fabricated as part of a second one of the one or more low-resistance interconnect layers of the upper superstructure, wherein at least one inductor fabricated as part of the first one of the one or more low-resistance interconnect layers is positioned sufficiently close to at least one inductor fabricated as part of the second one of the one or more low-resistance interconnect layers so as to function as a transformer.
19. The invention of claim 18 , wherein the integrated circuit structure includes at least one field effect transistor having a conductive aligned supplemental gate.
20. The invention of claim 18 , wherein the handle wafer is principally silicon having a bonding layer of silicon dioxide, and the integrated circuit structure is attached to the bonding layer.