Ultra-Short Pulsed Laser Annealing Effects on MoS<sub>2</sub> Transistors with Asymmetric and Symmetric Contacts

Ultra-Short Pulsed Laser Annealing Effects on MoS<sub>2</sub> Transistors with Asymmetric and Symmetric Contacts

The ultra-short pulsed laser annealing process enhances the performance of MoS<sub>2</sub> thin film transistors (TFTs) without thermal damage on plastic substrates. However, there has been insufficient investigation into how much improvement can be brought about by the laser process. In...

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Main Authors: Hyeokjin Kwon, Seunghun Baik, Jae Eun Jang, Jaewon Jang, Sunkook Kim, Costas P. Grigoropoulos, Hyuk-Jun Kwon
Format: Article
Language:English
Published: MDPI AG 2019-02-01
Series:Electronics
Subjects:
pulsed laser
transistor
contact
MoS<sub>2</sub>
Online Access:https://www.mdpi.com/2079-9292/8/2/222
id doaj-445574aa2eee4b04af1357d535b16906
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spelling doaj-445574aa2eee4b04af1357d535b169062020-11-25T01:11:21ZengMDPI AGElectronics2079-92922019-02-018222210.3390/electronics8020222electronics8020222Ultra-Short Pulsed Laser Annealing Effects on MoS<sub>2</sub> Transistors with Asymmetric and Symmetric ContactsHyeokjin Kwon0Seunghun Baik1Jae Eun Jang2Jaewon Jang3Sunkook Kim4Costas P. Grigoropoulos5Hyuk-Jun Kwon6Department of Information and Communication Engineering, DGIST, Daegu 42988, KoreaDepartment of Information and Communication Engineering, DGIST, Daegu 42988, KoreaDepartment of Information and Communication Engineering, DGIST, Daegu 42988, KoreaSchool of Electronics Engineering, Kyungpook National University, Daegu 41566, KoreaSchool of Advanced Materials Science &amp; Engineering, Sungkyunkwan University, Suwon 16419, KoreaDepartment of Mechanical Engineering, University of California, Berkeley, CA 94720, USADepartment of Information and Communication Engineering, DGIST, Daegu 42988, KoreaThe ultra-short pulsed laser annealing process enhances the performance of MoS<sub>2</sub> thin film transistors (TFTs) without thermal damage on plastic substrates. However, there has been insufficient investigation into how much improvement can be brought about by the laser process. In this paper, we observed how the parameters of TFTs, i.e., mobility, subthreshold swing, I<sub>on</sub>/I<sub>off</sub> ratio, and V<sub>th</sub>, changed as the TFTs&#8217; contacts were (1) not annealed, (2) annealed on one side, or (3) annealed on both sides. The results showed that the linear effective mobility (&#956;<sub>eff_lin</sub>) increased from 13.14 [cm<sup>2</sup>/Vs] (not annealed) to 18.84 (one side annealed) to 24.91 (both sides annealed). Also, I<sub>on</sub>/I<sub>off</sub> ratio increased from <inline-formula> <math display="inline"> <semantics> <mrow> <mn>2.27</mn> <mo>&#215;</mo> <msup> <mrow> <mn>10</mn> </mrow> <mn>5</mn> </msup> </mrow> </semantics> </math> </inline-formula> (not annealed) to <inline-formula> <math display="inline"> <semantics> <mrow> <mn>3.14</mn> <mo>&#215;</mo> <msup> <mrow> <mn>10</mn> </mrow> <mn>5</mn> </msup> </mrow> </semantics> </math> </inline-formula> (one side annealed) to <inline-formula> <math display="inline"> <semantics> <mrow> <mn>4.81</mn> <mo>&#215;</mo> <msup> <mrow> <mn>10</mn> </mrow> <mn>5</mn> </msup> <mo>&nbsp;</mo> </mrow> </semantics> </math> </inline-formula>(both sides annealed), with V<sub>th</sub> shifting to negative direction. Analyzing the main reason for the improvement through the Y function method (YFM), we found that both the contact resistance (R<sub>c</sub>) and the channel interface resistance (R<sub>ch</sub>) improves after the pulsed laser annealings under different conditions. Moreover, the R<sub>c</sub> enhances more dramatically than the R<sub>ch</sub> does. In conclusion, our picosecond laser annealing improves the performance of TFTs (especially, the R<sub>c</sub>) in direct proportion to the number of annealings applied. The results will contribute to the investigation about correlations between the laser annealing process and the performance of devices.https://www.mdpi.com/2079-9292/8/2/222pulsed lasertransistorcontactMoS<sub>2</sub>
collection DOAJ
language English
format Article
sources DOAJ
author Hyeokjin Kwon
Seunghun Baik
Jae Eun Jang
Jaewon Jang
Sunkook Kim
Costas P. Grigoropoulos
Hyuk-Jun Kwon
spellingShingle Hyeokjin Kwon
Seunghun Baik
Jae Eun Jang
Jaewon Jang
Sunkook Kim
Costas P. Grigoropoulos
Hyuk-Jun Kwon
Ultra-Short Pulsed Laser Annealing Effects on MoS<sub>2</sub> Transistors with Asymmetric and Symmetric Contacts
Electronics
pulsed laser
transistor
contact
MoS<sub>2</sub>
author_facet Hyeokjin Kwon
Seunghun Baik
Jae Eun Jang
Jaewon Jang
Sunkook Kim
Costas P. Grigoropoulos
Hyuk-Jun Kwon
author_sort Hyeokjin Kwon
title Ultra-Short Pulsed Laser Annealing Effects on MoS<sub>2</sub> Transistors with Asymmetric and Symmetric Contacts
title_short Ultra-Short Pulsed Laser Annealing Effects on MoS<sub>2</sub> Transistors with Asymmetric and Symmetric Contacts
title_full Ultra-Short Pulsed Laser Annealing Effects on MoS<sub>2</sub> Transistors with Asymmetric and Symmetric Contacts
title_fullStr Ultra-Short Pulsed Laser Annealing Effects on MoS<sub>2</sub> Transistors with Asymmetric and Symmetric Contacts
title_full_unstemmed Ultra-Short Pulsed Laser Annealing Effects on MoS<sub>2</sub> Transistors with Asymmetric and Symmetric Contacts
title_sort ultra-short pulsed laser annealing effects on mos<sub>2</sub> transistors with asymmetric and symmetric contacts
publisher MDPI AG
series Electronics
issn 2079-9292
publishDate 2019-02-01
description The ultra-short pulsed laser annealing process enhances the performance of MoS<sub>2</sub> thin film transistors (TFTs) without thermal damage on plastic substrates. However, there has been insufficient investigation into how much improvement can be brought about by the laser process. In this paper, we observed how the parameters of TFTs, i.e., mobility, subthreshold swing, I<sub>on</sub>/I<sub>off</sub> ratio, and V<sub>th</sub>, changed as the TFTs&#8217; contacts were (1) not annealed, (2) annealed on one side, or (3) annealed on both sides. The results showed that the linear effective mobility (&#956;<sub>eff_lin</sub>) increased from 13.14 [cm<sup>2</sup>/Vs] (not annealed) to 18.84 (one side annealed) to 24.91 (both sides annealed). Also, I<sub>on</sub>/I<sub>off</sub> ratio increased from <inline-formula> <math display="inline"> <semantics> <mrow> <mn>2.27</mn> <mo>&#215;</mo> <msup> <mrow> <mn>10</mn> </mrow> <mn>5</mn> </msup> </mrow> </semantics> </math> </inline-formula> (not annealed) to <inline-formula> <math display="inline"> <semantics> <mrow> <mn>3.14</mn> <mo>&#215;</mo> <msup> <mrow> <mn>10</mn> </mrow> <mn>5</mn> </msup> </mrow> </semantics> </math> </inline-formula> (one side annealed) to <inline-formula> <math display="inline"> <semantics> <mrow> <mn>4.81</mn> <mo>&#215;</mo> <msup> <mrow> <mn>10</mn> </mrow> <mn>5</mn> </msup> <mo>&nbsp;</mo> </mrow> </semantics> </math> </inline-formula>(both sides annealed), with V<sub>th</sub> shifting to negative direction. Analyzing the main reason for the improvement through the Y function method (YFM), we found that both the contact resistance (R<sub>c</sub>) and the channel interface resistance (R<sub>ch</sub>) improves after the pulsed laser annealings under different conditions. Moreover, the R<sub>c</sub> enhances more dramatically than the R<sub>ch</sub> does. In conclusion, our picosecond laser annealing improves the performance of TFTs (especially, the R<sub>c</sub>) in direct proportion to the number of annealings applied. The results will contribute to the investigation about correlations between the laser annealing process and the performance of devices.
topic pulsed laser
transistor
contact
MoS<sub>2</sub>
url https://www.mdpi.com/2079-9292/8/2/222
work_keys_str_mv AT hyeokjinkwon ultrashortpulsedlaserannealingeffectsonmossub2subtransistorswithasymmetricandsymmetriccontacts
AT seunghunbaik ultrashortpulsedlaserannealingeffectsonmossub2subtransistorswithasymmetricandsymmetriccontacts
AT jaeeunjang ultrashortpulsedlaserannealingeffectsonmossub2subtransistorswithasymmetricandsymmetriccontacts
AT jaewonjang ultrashortpulsedlaserannealingeffectsonmossub2subtransistorswithasymmetricandsymmetriccontacts
AT sunkookkim ultrashortpulsedlaserannealingeffectsonmossub2subtransistorswithasymmetricandsymmetriccontacts
AT costaspgrigoropoulos ultrashortpulsedlaserannealingeffectsonmossub2subtransistorswithasymmetricandsymmetriccontacts
AT hyukjunkwon ultrashortpulsedlaserannealingeffectsonmossub2subtransistorswithasymmetricandsymmetriccontacts
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