EMS TUNABLE TRANSISTOR

• US 20120212289A1
• Filed: 02/23/2011
• Published: 08/23/2012
• Est. Priority Date: 02/23/2011
• Status: Active Grant

• Current Assignee: Snaptrack Incorporated (Qualcomm, Inc.)
• Original Assignee: Qualcomm MEMS Technologies Incorporated (Qualcomm, Inc.)
• Inventors: Kothari, Manish, Govil, Alok
• Granted Patent: US 8,294,184 B2
• Time in Patent Office: Days
• US Class Current: 327/581
• CPC Class Codes: H01L 29/42384 for thin film field effect transistors, e.g. characterised by the thickness or the shape of the insulator or the dimensions, the shape or the lay-out of the conductor
• CPC Class Codes: H01L 29/4908 for thin film semiconductor, e.g. gate of TFT
• CPC Class Codes: H01L 29/515 with cavities, e.g. containing a gas

Abstract

A field effect transistor comprises an electrostatically moveable gate electrode. The moveable gate is supported by at least two posts, and the source, drain, and channel of the transistor are centrally located under the moveable layer. At least one electrode is positioned on at least two sides of the source, drain, and channel.

Claims

1. A field effect transistor comprising:

a moveable gate supported by at least two posts and configured to deform centrally between the at least two posts;

a source;

a drain;

a doped semi-conductor channel disposed between the source and the drain and located under the movable gate; and

one or more electrodes disposed on at least two sides of the source, the drain and the doped semi-conductor channel and configured to drive the moveable gate towards the doped semi-conductor channel.

2. The transistor of claim 1, wherein the one or more electrodes drive the movable gate towards the doped semi-conductor channel when a voltage difference is present between the one or more electrodes and the moveable gate.

3. The transistor of claim 1, the doped semi-conductor channel conducts an electric current when the movable gate is driven towards the doped semi-conductor channel.

4. The transistor of claim 1, wherein at least one transistor characteristic is based at least in part on a distance between the moveable gate and the doped semi-conductor channel.

5. The transistor of claim 1, wherein the at least one transistor characteristic comprises at least one of a drain current, transconductance, a cut-off frequency, a breakdown voltage, a leakage current, and a capacitance between at least two of the source, gate and drain of the field effect transistor.

6. The transistor of claim 4, wherein the drain current increases as the distance between the moveable gate and the doped semi-conductor channel decreases.

7. The transistor of claim 1, wherein the one or more electrodes is further configured to drive the movable gate towards the one or more electrodes.

8. The transistor of claim 1, wherein the one or more electrodes is further configured to drive the moveable gate towards at least one of the source and the drain.

9. The transistor of claim 1, wherein the moveable gate is driven towards the doped semi-conductor channel due to an electrostatic force.

10. The transistor of claim 1, wherein the moveable gate is positioned above the drain, the source, and the doped semi-conductor channel and wherein the one or more electrodes is positioned below the moveable gate.

11. The transistor of claim 1, wherein a distance between the movable gate and the doped semi-conductor channel is changed and substantially fixed after the fabrication of the transistor, and wherein the change is based at least in part on at least one transistor characteristic.

12. The transistor of claim 1, wherein the distance between the movable gate and the doped semi-conductor channel is varied based at least in part on an electrical signal.

13. The transistor of claim 12, wherein the electrical signal is based on, at least in part, an electrical feedback circuit.

14. The transistor of claim 1, wherein a spring force of the moveable gate drives the moveable gate away from the doped semi-conductor channel.

15. A method of operating a field effect transistor, the method comprising electrostatically moving a gate of said transistor toward a source, a drain and a doped semi-conductor channel of said transistor, wherein the gate is supported by at least two posts and is configured to deform centrally towards the source, the drain, and the doped semiconductor channel, and wherein one or more electrodes are disposed on at least two sides of the source, the drain and the dope semi-conductor channel.

16. The method of claim 15, wherein the gate is moved towards or away from the doped semi-conductor channel due to the voltage difference between the one or more electrodes and the gate.

17. The method of claim 15, the doped semi-conductor channel conducts an electric current when the movable gate is driven towards the doped semi-conductor channel.

18. The method of claim 15, wherein at least one of a drain current, transconductance, and a cut-off frequency of the field effect transistor is based at least in part on a distance between the moveable gate and the doped semi-conductor channel.

19. The method of claim 18, comprising increasing the drain current as the distance between the gate and the doped semi-conductor channel decreases.

20. The method of claim 15, comprising moving the gate towards the one or more electrodes.

21. The method of claim 15, further comprising moving the gate towards at least one of a source and a drain.

22. The method of claim 15, further comprising moving the gate away from the source, the drain, and the doped semiconductor channel based on a spring force of the gate.

27. The transistor of claim 21, wherein a spring force of the moveable gate drives the moveable gate away from the doped semi-conductor channel.

23. A field effect transistor comprising:

a moveable gate supported by at least two posts and configured to deform centrally between the at least two posts;

a source;

a drain;

a doped semi-conductor channel disposed between the source and the drain and located under the movable gate; and

means for moving the gate towards or away from the doped semi-conductor channel, wherein the moving means is disposed on at least two sides of the source, the drain and the doped semi-conductor channel.

24. The transistor of claim 23, wherein the moving means comprises one or more electrodes.

25. The transistor of claim 23, wherein the moving means uses an electrostatic force to move the gate towards the doped semi-conductor channel.

26. The transistor of claim 23, wherein the doped semi-conductor channel conducts an electric current when the movable gate is moved towards the doped semi-conductor channel.