High transmittance silicon terahertz polarizer using wafer bonding technology

Ting Yang Yu; Hsin Cheng Tsai; Shiang Yu Wang; Chih-Wei Luo; Kuan-Neng Chen

doi:10.1117/12.2187435

High transmittance silicon terahertz polarizer using wafer bonding technology

Ting Yang Yu, Hsin Cheng Tsai, Shiang Yu Wang, Chih-Wei Luo, Kuan-Neng Chen^*

^*Corresponding author for this work

Department of Electrophysics

Research output: Chapter in Book/Report/Conference proceeding › Conference contribution › peer-review

2 Scopus citations

Abstract

Due to the difficulties faced in fabricating robust Terahertz (THz) optical components with low Fresnel reflection loss, the need to increase the efficiency of THz system with reduced cost is still considered as one of the most essential tasks. In this report, a new low cost THz polarizer with robust structure is proposed and demonstrated. This new THz wire grid polarizer was based on an anti-reflection (AR) layer fabricated with low temperature metal bonding and deep reactive ion etching (DRIE). After patterning Cu wire gratings and the corresponding In/Sn solder ring on the individual silicon wafers, the inner gratings were sealed by wafer-level Cu to In/Sn guard ring bonding, providing the protection against humidity oxidation and corrosion. With the low eutectic melting point of In/Sn solder, wafers could be bonded face to face below 150°C. Two anti-reflection layers on both outward surfaces were fabricated by DRIE. With the mixing of empty holes and silicon, the effective refractive index was designed to be the square root of the silicon refractive index. The central frequency of the anti-reflection layers was designed between 0.5THz to 2THz with an approximate bandwidth of 0.5THz. The samples were measured with a commercial free-standing wire grid polarizer by a THz time domain spectroscopy (THz-TDS) from 0.2THz to 2.2THz. The power transmittance is close to 100% at central frequency. Extinction ratio of the polarizer is between 20dB to 40dB depending on the frequency. The advantages of this new polarizer include high transmittance, robust structure and low cost with no precision optical alignment required.

Original language	English
Title of host publication	Terahertz Emitters, Receivers, and Applications VI
Editors	Alexei N. Baranov, Manijeh Razeghi, Dimitris Pavlidis, John M. Zavada
Publisher	SPIE-INT SOC OPTICAL ENGINEERING
Number of pages	7
ISBN (Electronic)	9781628417517
DOIs	https://doi.org/10.1117/12.2187435
State	Published - 2015
Event	Terahertz Emitters, Receivers, and Applications VI - San Diego, United States Duration: 9 Aug 2015 → 10 Aug 2015

Publication series

Name	Proceedings of SPIE - The International Society for Optical Engineering
Volume	9585
ISSN (Print)	0277-786X
ISSN (Electronic)	1996-756X

Conference

Conference	Terahertz Emitters, Receivers, and Applications VI
Country/Territory	United States
City	San Diego
Period	9/08/15 → 10/08/15

Keywords

DRIE
Wire grid polarizer
anti-reflection
eutectic point
terahertz wave
wafer bonding

Access to Document

10.1117/12.2187435

Cite this

Yu, T. Y., Tsai, H. C., Wang, S. Y., Luo, C.-W., & Chen, K.-N. (2015). High transmittance silicon terahertz polarizer using wafer bonding technology. In A. N. Baranov, M. Razeghi, D. Pavlidis, & J. M. Zavada (Eds.), Terahertz Emitters, Receivers, and Applications VI Article 95850L (Proceedings of SPIE - The International Society for Optical Engineering; Vol. 9585). SPIE-INT SOC OPTICAL ENGINEERING. https://doi.org/10.1117/12.2187435

Yu, Ting Yang ; Tsai, Hsin Cheng ; Wang, Shiang Yu et al. / High transmittance silicon terahertz polarizer using wafer bonding technology. Terahertz Emitters, Receivers, and Applications VI. editor / Alexei N. Baranov ; Manijeh Razeghi ; Dimitris Pavlidis ; John M. Zavada. SPIE-INT SOC OPTICAL ENGINEERING, 2015. (Proceedings of SPIE - The International Society for Optical Engineering).

@inproceedings{14de3c5aa63342c68ba8809f30b2e3b6,

title = "High transmittance silicon terahertz polarizer using wafer bonding technology",

abstract = "Due to the difficulties faced in fabricating robust Terahertz (THz) optical components with low Fresnel reflection loss, the need to increase the efficiency of THz system with reduced cost is still considered as one of the most essential tasks. In this report, a new low cost THz polarizer with robust structure is proposed and demonstrated. This new THz wire grid polarizer was based on an anti-reflection (AR) layer fabricated with low temperature metal bonding and deep reactive ion etching (DRIE). After patterning Cu wire gratings and the corresponding In/Sn solder ring on the individual silicon wafers, the inner gratings were sealed by wafer-level Cu to In/Sn guard ring bonding, providing the protection against humidity oxidation and corrosion. With the low eutectic melting point of In/Sn solder, wafers could be bonded face to face below 150°C. Two anti-reflection layers on both outward surfaces were fabricated by DRIE. With the mixing of empty holes and silicon, the effective refractive index was designed to be the square root of the silicon refractive index. The central frequency of the anti-reflection layers was designed between 0.5THz to 2THz with an approximate bandwidth of 0.5THz. The samples were measured with a commercial free-standing wire grid polarizer by a THz time domain spectroscopy (THz-TDS) from 0.2THz to 2.2THz. The power transmittance is close to 100% at central frequency. Extinction ratio of the polarizer is between 20dB to 40dB depending on the frequency. The advantages of this new polarizer include high transmittance, robust structure and low cost with no precision optical alignment required.",

keywords = "DRIE, Wire grid polarizer, anti-reflection, eutectic point, terahertz wave, wafer bonding",

author = "Yu, {Ting Yang} and Tsai, {Hsin Cheng} and Wang, {Shiang Yu} and Chih-Wei Luo and Kuan-Neng Chen",

note = "Publisher Copyright: {\textcopyright} 2015 SPIE.; Terahertz Emitters, Receivers, and Applications VI ; Conference date: 09-08-2015 Through 10-08-2015",

year = "2015",

doi = "10.1117/12.2187435",

language = "English",

series = "Proceedings of SPIE - The International Society for Optical Engineering",

publisher = "SPIE-INT SOC OPTICAL ENGINEERING",

editor = "Baranov, {Alexei N.} and Manijeh Razeghi and Dimitris Pavlidis and Zavada, {John M.}",

booktitle = "Terahertz Emitters, Receivers, and Applications VI",

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Yu, TY, Tsai, HC, Wang, SY, Luo, C-W & Chen, K-N 2015, High transmittance silicon terahertz polarizer using wafer bonding technology. in AN Baranov, M Razeghi, D Pavlidis & JM Zavada (eds), Terahertz Emitters, Receivers, and Applications VI., 95850L, Proceedings of SPIE - The International Society for Optical Engineering, vol. 9585, SPIE-INT SOC OPTICAL ENGINEERING, Terahertz Emitters, Receivers, and Applications VI, San Diego, United States, 9/08/15. https://doi.org/10.1117/12.2187435

High transmittance silicon terahertz polarizer using wafer bonding technology. / Yu, Ting Yang; Tsai, Hsin Cheng; Wang, Shiang Yu et al.
Terahertz Emitters, Receivers, and Applications VI. ed. / Alexei N. Baranov; Manijeh Razeghi; Dimitris Pavlidis; John M. Zavada. SPIE-INT SOC OPTICAL ENGINEERING, 2015. 95850L (Proceedings of SPIE - The International Society for Optical Engineering; Vol. 9585).

Research output: Chapter in Book/Report/Conference proceeding › Conference contribution › peer-review

TY - GEN

T1 - High transmittance silicon terahertz polarizer using wafer bonding technology

AU - Yu, Ting Yang

AU - Tsai, Hsin Cheng

AU - Wang, Shiang Yu

AU - Luo, Chih-Wei

AU - Chen, Kuan-Neng

PY - 2015

Y1 - 2015

N2 - Due to the difficulties faced in fabricating robust Terahertz (THz) optical components with low Fresnel reflection loss, the need to increase the efficiency of THz system with reduced cost is still considered as one of the most essential tasks. In this report, a new low cost THz polarizer with robust structure is proposed and demonstrated. This new THz wire grid polarizer was based on an anti-reflection (AR) layer fabricated with low temperature metal bonding and deep reactive ion etching (DRIE). After patterning Cu wire gratings and the corresponding In/Sn solder ring on the individual silicon wafers, the inner gratings were sealed by wafer-level Cu to In/Sn guard ring bonding, providing the protection against humidity oxidation and corrosion. With the low eutectic melting point of In/Sn solder, wafers could be bonded face to face below 150°C. Two anti-reflection layers on both outward surfaces were fabricated by DRIE. With the mixing of empty holes and silicon, the effective refractive index was designed to be the square root of the silicon refractive index. The central frequency of the anti-reflection layers was designed between 0.5THz to 2THz with an approximate bandwidth of 0.5THz. The samples were measured with a commercial free-standing wire grid polarizer by a THz time domain spectroscopy (THz-TDS) from 0.2THz to 2.2THz. The power transmittance is close to 100% at central frequency. Extinction ratio of the polarizer is between 20dB to 40dB depending on the frequency. The advantages of this new polarizer include high transmittance, robust structure and low cost with no precision optical alignment required.

AB - Due to the difficulties faced in fabricating robust Terahertz (THz) optical components with low Fresnel reflection loss, the need to increase the efficiency of THz system with reduced cost is still considered as one of the most essential tasks. In this report, a new low cost THz polarizer with robust structure is proposed and demonstrated. This new THz wire grid polarizer was based on an anti-reflection (AR) layer fabricated with low temperature metal bonding and deep reactive ion etching (DRIE). After patterning Cu wire gratings and the corresponding In/Sn solder ring on the individual silicon wafers, the inner gratings were sealed by wafer-level Cu to In/Sn guard ring bonding, providing the protection against humidity oxidation and corrosion. With the low eutectic melting point of In/Sn solder, wafers could be bonded face to face below 150°C. Two anti-reflection layers on both outward surfaces were fabricated by DRIE. With the mixing of empty holes and silicon, the effective refractive index was designed to be the square root of the silicon refractive index. The central frequency of the anti-reflection layers was designed between 0.5THz to 2THz with an approximate bandwidth of 0.5THz. The samples were measured with a commercial free-standing wire grid polarizer by a THz time domain spectroscopy (THz-TDS) from 0.2THz to 2.2THz. The power transmittance is close to 100% at central frequency. Extinction ratio of the polarizer is between 20dB to 40dB depending on the frequency. The advantages of this new polarizer include high transmittance, robust structure and low cost with no precision optical alignment required.

KW - DRIE

KW - Wire grid polarizer

KW - anti-reflection

KW - eutectic point

KW - terahertz wave

KW - wafer bonding

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U2 - 10.1117/12.2187435

DO - 10.1117/12.2187435

M3 - Conference contribution

AN - SCOPUS:84951969806

T3 - Proceedings of SPIE - The International Society for Optical Engineering

BT - Terahertz Emitters, Receivers, and Applications VI

A2 - Baranov, Alexei N.

A2 - Razeghi, Manijeh

A2 - Pavlidis, Dimitris

A2 - Zavada, John M.

PB - SPIE-INT SOC OPTICAL ENGINEERING

T2 - Terahertz Emitters, Receivers, and Applications VI

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ER -

Yu TY, Tsai HC, Wang SY, Luo CW , Chen KN. High transmittance silicon terahertz polarizer using wafer bonding technology. In Baranov AN, Razeghi M, Pavlidis D, Zavada JM, editors, Terahertz Emitters, Receivers, and Applications VI. SPIE-INT SOC OPTICAL ENGINEERING. 2015. 95850L. (Proceedings of SPIE - The International Society for Optical Engineering). doi: 10.1117/12.2187435

High transmittance silicon terahertz polarizer using wafer bonding technology

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