Method and device for protecting interferometric modulators from electrostatic discharge

• US 7,405,861 B2
• Filed: 05/02/2005
• Issued: 07/29/2008
• Est. Priority Date: 09/27/2004
• Status: Expired due to Fees

• Current Assignee: Snaptrack Incorporated (Qualcomm, Inc.)
• Original Assignee: IDC, LLC
• Inventors: Floyd, Philip D.
• Primary Examiner(s): Sugarman; Scott J.
• Assistant Examiner(s): PINKNEY, DAWAYNE
• Application Number:
  US11/119,651
• Publication Number:
  US 20060077504A1
• Time in Patent Office: 1,184 Days
• Field of Search: 359224-225, 359230-231, 359/245, 359237-238, 359/240, 359/247, 359/267, 359290-291, 359/298, 359/649
• US Class Current: 359/290
• CPC Class Codes: B81B 2201/047 Optical MEMS not provided for in B81B2201/042 - B81B2201/045
• CPC Class Codes: B81B 7/0012 Protection against reverse engineering, unauthorised use, use in unintended manner, wrong insertion or pin assignment
• CPC Class Codes: G02B 26/001 based on interference in an adjustable optical cavity interference filters G02B5/28; devices or arrangements using multiple reflections in spectrometry or monochromators G01J3/26
• CPC Class Codes: H01L 27/0248 for electrical or thermal protection, e.g. electrostatic discharge [ESD] protection

Abstract

A MEMS device such as an interferometric modulator includes an integrated ESD protection element capable of shunting to ground an excess current carried by an electrical conductor in the MEMS device. The protection element may be a diode and may be formed by depositing a plurality of doped semiconductor layers over the substrate on which the MEMS device is formed.

Claims

1. A MEMS device comprising:

a moveable element;

an electrical conductor configured to carry an actuation current that is effective to actuate the moveable element; and

a protection element operably attached to the electrical conductor and configured to at least partially shunt to ground an excess current carried by the electrical conductor, the protection element comprising a diode,

the moveable element, electrical conductor and protection element being integrally formed over a substrate.

2. The MEMS device of claim 1 in which the diode is selected from the group consisting of back-to-back Zener diode, standard Zener diode, low capacitance Zener diode, symmetrical Zener diode, and low capacitance symmetrical diode.

3. The MEMS device of claim 1 in which the diode comprises a plurality of doped semiconductor layers.

4. The MEMS device of claim 1 in which the moveable element, electrical conductor and protection element are at a substantially same level over the substrate.

5. An interferometric modulator comprising:

an electrode integrated with a substrate and configured to carry an actuation current; and

a protection element connected to the electrode and configured to at least partially shunt to ground an excess current carried by the electrode, the protection element comprising a diode, the protection element being integrally formed with the substrate.

6. The interferometric modulator of claim 5 in which the diode is selected from the group consisting of back-to-back Zener diode, standard Zener diode, low capacitance Zener diode, symmetrical Zener diode, and low capacitance symmetrical diode.

7. The interferometric modulator of claim 5 in which the diode comprises a plurality of doped semiconductor layers.

8. The interferometric modulator of claim 5 in which the electrode and the protection element are at a substantially same level over the substrate.

9. The interferometric modulator of claim 5 further comprising a mirror operably attached to the electrode.

10. The interferometric modulator of claim 9 further comprising a second mirror spaced apart from and substantially parallel to the first mirror.

11. The interferometric modulator of claim 10 further comprising a second electrode operably attached to the second mirror.

12. The interferometric modulator of claim 11 further comprising a second protection element operably attached to the second electrode and configured to at least partially shunt to ground a second excess current carried by the second electrode.

13. The interferometric modulator of claim 12 in which the second protection element comprises a second diode.

14. The interferometric modulator of claim 13 in which the second diode is selected from the group consisting of back-to-back Zener diode, standard Zener diode, low capacitance Zener diode, symmetrical Zener diode, and low capacitance symmetrical diode.

15. A display device comprising;

a substrate;

a plurality of interferometric modulators formed over the substrate; and

a plurality of protection elements integrally formed with the plurality of interferometric modulators over the substrate, the plurality of protection elements comprising a plurality of doped semiconductor layers;

the plurality of protection elements being electrically connected to at least partially protect the plurality of interferometric modulators from an electrostatic discharge.

16. The display device of claim 15 in which the plurality of interferometric modulators are connected by row and column lines.

17. The display device of claim 16 in which the row and column lines are attached to the plurality of protection elements.