Cd1−xZnxS high performance TCR material for uncooled microbolometers used in infrared sensors and method of making same

• US 7,527,999 B2
• Filed: 12/06/2005
• Issued: 05/05/2009
• Est. Priority Date: 12/06/2005
• Status: Expired due to Fees

• Current Assignee: TECHNION RESEARCH AND DEVELOPMENT FOUNDATION, LTD. (Technion-Israel Institute Of Technology)
• Original Assignee: TECHNION RESEARCH AND DEVELOPMENT FOUNDATION, LTD. (Technion-Israel Institute Of Technology)
• Inventors: Sinai, Yehuda, Stolyarova, Sara, Weinstein, Moshe, Shai, Avi, Nemirovsky, Yael
• Primary Examiner(s): Ghyka; Alexander G
• Application Number:
  US11/294,677
• Publication Number:
  US 20070128361A1
• Time in Patent Office: 1,246 Days
• Field of Search: 257/431, 438/57
• US Class Current: 438/57
• CPC Class Codes: C23C 14/0629 of zinc, cadmium or mercury
• CPC Class Codes: C23C 14/5806 Thermal treatment
• CPC Class Codes: C23C 16/306 AII BVI compounds, where A is Zn, Cd or Hg and B is S, Se or Te
• CPC Class Codes: G01J 5/20 using resistors, thermistors or semiconductors sensitive to radiation, e.g. photoconductive devices
• CPC Class Codes: H01L 21/02381 Silicon, silicon germanium, germanium
• CPC Class Codes: H01L 21/02422 Non-crystalline insulating materials, e.g. glass, polymers
• CPC Class Codes: H01L 21/02488 Insulating materials
• CPC Class Codes: H01L 21/02557 Sulfides
• CPC Class Codes: H01L 21/0262 Reduction or decomposition of gaseous compounds, e.g. CVD

Abstract

A Cd_1-xZn_xS film material, with a high value of thermal coefficient of resistance, in the range of 1.5% to 3.7%. The Cd_1-xZn_xS material has excellent characteristics for use in a microbolometer-type uncooled infrared sensor. The film material can be deposited on microbolometer membranes or any other wafer for different applications. The film material can be deposited using the MOCVD technique, thermal evaporation or a different technique to form the film material over the wafer. The Cd_1-xZn_xS properties can be modified controlling certain deposition parameters and different annealing techniques. The process is performed at temperature compatible with CMOS technology.

Claims

1. A film material for microbolometers used in uncooled infrared sensors comprising:

at least one of a cadmium component and a zinc component; and

a sulfur component,

said film material being represented as Cd_1-xZn_xS, wherein x has a value in the range of approximately 0-0.06, and wherein said value of thermal coefficient of resistance (TCR) is in the range of 1.5% to 3.7%, said film material being capable of deposition to form a thickness of no more than approximately 2000 Angstrom on a wafer,

said deposited film material providing a relatively high value of TCR and being capable of fabrication at temperatures compatible with and not harmful to CMOS devices present on said wafer.

2. The material of claim 1, wherein said deposited film material is applied to a microbolometer.

3. The material of claim 1, wherein said deposited film material is applied to an uncooled infrared detector.

4. The material of claim 2, wherein a layer of ZnS is applied to said microbolometer as a passivation layer.

5. The material of claim 1, wherein said material is stable in the sun and is thereby insensitive to bleaching.

6. The material of claim 1, wherein said material is deposited by thermal evaporation.

7. The material of claim 1, wherein said material is deposited by a Metal-Organic Chemical Vapor Deposition (MOCVD) technique.

8. The material of claim 1, for use in a predictive maintenance device.

9. The material of claim 1, for use in a fire safety device.

10. The material of claim 1, for use in security systems.

11. The material of claim 1, for use in night vision systems.

12. The material of claim 1, for use in living being detection sensors.

13. The material of claim 1, for use in satellite photography.

14. The material of claim 1, for use in ultrasonic wave detection.

15. A film material for microbolometers used in uncooled infrared sensors manufactured by a method comprising:

performing a growth process to obtain a film material comprising;

at least one of a cadmium component and a zinc component; and

a sulfur component,

said film material being represented by Cd_1-xZn_xS,

wherein x has a value in the range of approximately 0-0.06, and wherein said value of thermal coefficient of resistance (TCR), is in the range of 1.5% to 3.7%, said film material being capable of deposition to form a thickness of no more than approximately 2000 Angstrom on a wafer;

depositing said film material on said wafer by establishing deposition parameters comprising;

pressure;

temperature, in order to determine resistivity of said deposited film material;

growth rate; and

wafer type;

and

performing an annealing technique,

such that said film material provides a relatively high value of TCR and is fabricated at temperatures compatible with and not harmful to GAGS devices present on said wafer.