High-yield spatial light modulator with light blocking layer

• US 5,818,095 A
• Filed: 08/11/1992
• Issued: 10/06/1998
• Est. Priority Date: 08/11/1992
• Status: Expired due to Fees

• Current Assignee: Texas Instruments, Inc.
• Original Assignee: Texas Instruments, Inc.
• Inventors: Sampsell, Jeffrey B.
• Primary Examiner(s): Prenty, Mark V.
• Application Number:
  US07/928,251
• Time in Patent Office: 2,247 Days
• Field of Search: 257/435, 257/758, 257/659
• US Class Current: 257/435
• CPC Class Codes: G02F 1/133512 Light shielding layers, e.g. black matrix G02F1/136209 takes precedence
• CPC Class Codes: G02F 1/136277 formed on a semiconductor substrate, e.g. of silicon
• CPC Class Codes: G02F 2203/12 spatial light modulator
• CPC Class Codes: G09F 9/372 the positions of the elements being controlled by the application of an electric field
• CPC Class Codes: H01L 23/552 Protection against radiation, e.g. light or electromagnetic waves
• CPC Class Codes: H01L 2924/00 Indexing scheme for arrangements or methods for connecting or disconnecting semiconductor or solid-state bodies as covered by H01L24/00
• CPC Class Codes: H01L 2924/0002 Not covered by any one of groups H01L24/00, H01L24/00 and H01L2224/00

Abstract

A semiconductor device with an optically active region which receives light, and has a layer of metal which blocks the light from the substrate. The substrate contains addressing circuitry which can experience current leakage if photocarriers are allowed to form by contact with light. A layer of metal is deposited as an integral part of the device to prevent the light from reaching the substrate.

Claims

1. A semiconductor device comprising:

a. a substrate;

b. electrically active regions in said substrate;

c. a first metal layer blocking substantially all light from reaching said substrate, comprising at least two regions, one region contacting at least one of said electrically active regions in said substrate, another region avoiding contact with said electrically active regions; and

d. a second metal layer overlaying said first metal layer and forming landing electrodes and addressing electrodes, wherein said addressing electrodes are in connection with said one region contacting said electrically active regions, and said landing electrodes are in connection with said another region avoiding contact with said electrically active regions.

2. The device of claim 1 wherein said substrate is silicon.

3. The device of claim 1 wherein said electrically active regions further comprise sources and drains of transistors.

4. The device of claim 1 wherein said device is a digital micromirror device.

5. The semiconductor device of claim 1 wherein said second metal layer blocks substantially all light from reaching the gap between said one region and said another region of said first metal layer.

6. A semiconductor spatial light modulator for modulating a beam of light, said device comprising:

a substrate;

an electrode layer overlying said substrate, said electrode layer divided into two regions, one region forming address electrodes, the other region forming landing electrodes, said landing and address electrodes separated by a gap in said electrode layer; and

a blocking layer underlying said electrode layer such that portions of said beam of light passing through said gap are blocked from reaching said substrate, wherein said blocking layer is comprised of at least two blocking regions, a first blocking region in electrical contact with said address electrodes and a second blocking region in electrical contact with said landing electrodes.

7. The device of claim 6 wherein said device is a digital micromirror device.

8. The device of claim 6 further comprising an oxide layer between said electrode layer and said blocking layer.

9. The device of claim 6 further comprising an oxide layer between said blocking layer and said substrate.

10. The device of claim 6 further comprising at least one electrically active region on said substrate, wherein at least a portion of said blocking layer is in electrical contact with said electrically active region.