Infrared sensor with precisely patterned Au-black absorption layer

Masaki Hirota, Shinichi Morita

Research output: Contribution to journalConference article

18 Citations (Scopus)

Abstract

Thermoelectric infrared sensors has been fabricated by adding to the CMOS process a surface micromachining technique and a highly accurate process for forming an infrared radiation absorbing layer. The sensor, or thermopile, consists of alternating areas of p-type and n-type polysilicon connected in series on a Si3N4 layer. An anisotropic etching technique using hydrazine is employed to form a thermally isolated membrane. While a Au-black layer for infrared radiation absorption provides the best absorption efficiency over a broad infrared wavelength region, it has been difficult to pattern the layer precisely. Patterning is accomplished by forming the Au-black layer by a low-pressure vapor deposition technique on amorphous Si and a PSG sacrificial layer and then removing it on PSG by the lift-off technique or wet etching PSG. This technique makes it possible to obtain a Au-black pattern with the same degree of accuracy as with the CMOS process. As a result, sensor performance has been improved and a device array has also been achieved. A simple sensor design method has been established by which simulations are easily conducted using a thermal equivalent circuit based on the CMOS process. Prototype sensors, having external dimensions of 160 μm×160 μm, achieved responsivity of 300, 149 and 60 V/W and a time constant of 2.0, 0.46 and 0.27 msec in the air, respectively. These performance figures surpass the performance reported to date for thermoelectric infrared sensors.

Original languageEnglish
Pages (from-to)623-634
Number of pages12
JournalProceedings of SPIE - The International Society for Optical Engineering
Volume3436
Issue number2
Publication statusPublished - Dec 1 1998
EventProceedings of the 1998 Conference on Infrared Technology and Applications XXIV. Part 1 (of 2) - San Diego, CA, USA
Duration: Jul 19 1998Jul 24 1998

Fingerprint

Infrared Sensor
Absorption
Infrared radiation
sensors
Sensors
Infrared Radiation
Sensor
CMOS
hydrazine
infrared radiation
Etching
etching
Thermopiles
radiation absorption
thermopiles
Surface micromachining
Anisotropic etching
Responsivity
Micromachining
Vapor deposition

All Science Journal Classification (ASJC) codes

  • Electronic, Optical and Magnetic Materials
  • Condensed Matter Physics
  • Computer Science Applications
  • Applied Mathematics
  • Electrical and Electronic Engineering

Cite this

Infrared sensor with precisely patterned Au-black absorption layer. / Hirota, Masaki; Morita, Shinichi.

In: Proceedings of SPIE - The International Society for Optical Engineering, Vol. 3436, No. 2, 01.12.1998, p. 623-634.

Research output: Contribution to journalConference article

@article{23d72d792128457381e24566a5816abb,
title = "Infrared sensor with precisely patterned Au-black absorption layer",
abstract = "Thermoelectric infrared sensors has been fabricated by adding to the CMOS process a surface micromachining technique and a highly accurate process for forming an infrared radiation absorbing layer. The sensor, or thermopile, consists of alternating areas of p-type and n-type polysilicon connected in series on a Si3N4 layer. An anisotropic etching technique using hydrazine is employed to form a thermally isolated membrane. While a Au-black layer for infrared radiation absorption provides the best absorption efficiency over a broad infrared wavelength region, it has been difficult to pattern the layer precisely. Patterning is accomplished by forming the Au-black layer by a low-pressure vapor deposition technique on amorphous Si and a PSG sacrificial layer and then removing it on PSG by the lift-off technique or wet etching PSG. This technique makes it possible to obtain a Au-black pattern with the same degree of accuracy as with the CMOS process. As a result, sensor performance has been improved and a device array has also been achieved. A simple sensor design method has been established by which simulations are easily conducted using a thermal equivalent circuit based on the CMOS process. Prototype sensors, having external dimensions of 160 μm×160 μm, achieved responsivity of 300, 149 and 60 V/W and a time constant of 2.0, 0.46 and 0.27 msec in the air, respectively. These performance figures surpass the performance reported to date for thermoelectric infrared sensors.",
author = "Masaki Hirota and Shinichi Morita",
year = "1998",
month = "12",
day = "1",
language = "English",
volume = "3436",
pages = "623--634",
journal = "Proceedings of SPIE - The International Society for Optical Engineering",
issn = "0277-786X",
publisher = "SPIE",
number = "2",

}

TY - JOUR

T1 - Infrared sensor with precisely patterned Au-black absorption layer

AU - Hirota, Masaki

AU - Morita, Shinichi

PY - 1998/12/1

Y1 - 1998/12/1

N2 - Thermoelectric infrared sensors has been fabricated by adding to the CMOS process a surface micromachining technique and a highly accurate process for forming an infrared radiation absorbing layer. The sensor, or thermopile, consists of alternating areas of p-type and n-type polysilicon connected in series on a Si3N4 layer. An anisotropic etching technique using hydrazine is employed to form a thermally isolated membrane. While a Au-black layer for infrared radiation absorption provides the best absorption efficiency over a broad infrared wavelength region, it has been difficult to pattern the layer precisely. Patterning is accomplished by forming the Au-black layer by a low-pressure vapor deposition technique on amorphous Si and a PSG sacrificial layer and then removing it on PSG by the lift-off technique or wet etching PSG. This technique makes it possible to obtain a Au-black pattern with the same degree of accuracy as with the CMOS process. As a result, sensor performance has been improved and a device array has also been achieved. A simple sensor design method has been established by which simulations are easily conducted using a thermal equivalent circuit based on the CMOS process. Prototype sensors, having external dimensions of 160 μm×160 μm, achieved responsivity of 300, 149 and 60 V/W and a time constant of 2.0, 0.46 and 0.27 msec in the air, respectively. These performance figures surpass the performance reported to date for thermoelectric infrared sensors.

AB - Thermoelectric infrared sensors has been fabricated by adding to the CMOS process a surface micromachining technique and a highly accurate process for forming an infrared radiation absorbing layer. The sensor, or thermopile, consists of alternating areas of p-type and n-type polysilicon connected in series on a Si3N4 layer. An anisotropic etching technique using hydrazine is employed to form a thermally isolated membrane. While a Au-black layer for infrared radiation absorption provides the best absorption efficiency over a broad infrared wavelength region, it has been difficult to pattern the layer precisely. Patterning is accomplished by forming the Au-black layer by a low-pressure vapor deposition technique on amorphous Si and a PSG sacrificial layer and then removing it on PSG by the lift-off technique or wet etching PSG. This technique makes it possible to obtain a Au-black pattern with the same degree of accuracy as with the CMOS process. As a result, sensor performance has been improved and a device array has also been achieved. A simple sensor design method has been established by which simulations are easily conducted using a thermal equivalent circuit based on the CMOS process. Prototype sensors, having external dimensions of 160 μm×160 μm, achieved responsivity of 300, 149 and 60 V/W and a time constant of 2.0, 0.46 and 0.27 msec in the air, respectively. These performance figures surpass the performance reported to date for thermoelectric infrared sensors.

UR - http://www.scopus.com/inward/record.url?scp=0032294745&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=0032294745&partnerID=8YFLogxK

M3 - Conference article

AN - SCOPUS:0032294745

VL - 3436

SP - 623

EP - 634

JO - Proceedings of SPIE - The International Society for Optical Engineering

JF - Proceedings of SPIE - The International Society for Optical Engineering

SN - 0277-786X

IS - 2

ER -