Light modulating device

• US 6,381,022 B1
• Filed: 07/27/2000
• Issued: 04/30/2002
• Est. Priority Date: 01/22/1992
• Status: Expired due to Fees

• Current Assignee: Northeastern University
• Original Assignee: Northeastern University
• Inventors: Zavracky, Paul M.
• Primary Examiner(s): Font, Frank G.
• Assistant Examiner(s): LEE, HWA S
• Application Number:
  US09/626,678
• Time in Patent Office: 642 Days
• Field of Search: 356/458, 356/451, 356/454, 356/519
• US Class Current: 356/454
• CPC Class Codes: G01J 3/0256 Compact construction
• CPC Class Codes: G01J 3/10 Arrangements of light sources specially adapted for spectrometry or colorimetry
• CPC Class Codes: G01J 3/26 using multiple reflection, e.g. Fabry-Perot interferometer, variable interference filters
• 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

Abstract

The present invention relates to microfabricated spectrometers including methods of making and using same. Microspectrometers can be formed in a single chip in which detectors and light sources can be monolithically integrated. The microspectrometer can be integrated into a sensor system to measure the optical and physical properties of solids and fluids.

Claims

1. A process for fabricating a light modulating device comprising the steps of:

forming a metal layer on a substrate;

forming a bridge support structure over the metal layer, the bridge support structure including an opening therein and a portion spaced above the substrate;

subsequently forming a lower mirror over the substrate through the opening in the bridge support structure;

positioning an upper mirror over the lower mirror and supported by the portion of the bridge support structure spaced above the substrate such that a gap is provided between a lower surface of the upper mirror and the lower mirror, the upper mirror being optically transmissive to incident radiation over a given spectral range.

2. The process of claim 1 wherein the step of forming the bridge support structure further comprises the step of forming a plurality of springs.

3. The process of claim 2 further comprising the step of electroplating a gold layer on the springs.

4. The process of claim 1 further comprising the step of forming a silicon dioxide layer on the substrate to form the lower mirror.

5. A process of fabricating a light modulating device comprising:

forming a plurality of support structures on or in a semiconductor substrate;

subsequently forming a plurality of lower mirrors in or over the substrate;

forming a sacrificial support material over each lower mirror;

forming a plurality of diaphragm elements over the sacrificial layer and which are positioned over each lower mirror; and

removing at least a portion of the sacrificial material from underneath each diaphragm element such that a gap is provided between a lower surface of each diaphragm bridge and each lower mirror.

6. The process of claim 5 further comprising forming a plurality of bias elements that support the diaphragm elements relative to the substrate.

7. The process of claim 5 wherein said diaphragm elements forming step further comprises forming a plurality of springs to support the support structures relative to the substrate.

8. The process of claims 5 wherein the process further comprises forming a device having an area of less than about 30 μ

m×

30 μ

m.

9. The process of claim 5 further comprising forming an actuator to move the diaphragm elements.

10. The process of claim 9 wherein the actuator forming step further comprises forming electrostatic force plate such that the actuator causes movement of said diaphragm elements relative to a detector by providing an electric field.

11. The process of claim 5 further comprising forming a set of electrodes under said diaphragm elements such that the position of said diaphragm elements can be determined by measuring capacitance between said electrodes and said support structures.

12. The process of claim 5 further comprising forming a detector in a semiconductor substrate.

13. The process of claim 5 further comprising forming a plurality of layers on the diaphragm elements.

14. The process of claim 5 further comprising forming a plurality of actuators in the semiconductor substrate to actuate movement of each diaphragm element.

15. The process of claim 9 further comprising forming a drive circuit in the substrate that is electrically connected to the actuator.

16. A process for fabricating a light modulating device over a substrate, comprising the steps of:

forming a spring structure over a substrate;

subsequently depositing a lower mirror on the substrate through an opening in the spring structure; and

attaching an upper mirror to the spring structure such that a gap is provided between a lower surface of the upper mirror and the lower mirror, the upper mirror being optically transmissive to incident radiation over a given spectral range.

17. The process of claim 16 further comprising:

forming a plurality of detectors on or in a semiconductor substrate.

18. The process of claim 16 further comprising forming an actuator to move the upper mirror.

19. The process of claim 18 wherein the actuator forming step further comprises forming electrostatic force plate such that the actuator causes movement of said upper mirror relative to a detector by providing an electric field.

20. The process of claim 18 further comprising forming a drive circuit in the substrate that is electrically connected to the actuator.