Characterizations of pulsed chemical vapor deposited-tungsten thin films for ultrahigh aspect ratio W-plug process

Soo Hyun Kim, Eui Sung Hwang, Seung Chul Ha, Seung Ho Pyi, Ho Jung Sun, Joo Wan Lee, Nohjung Kawk, Jun Ki Kim, Hyunchul Sohn, Jinwoong Kim

Research output: Contribution to journalArticle

20 Citations (Scopus)

Abstract

Tungsten (W) thin films were deposited using a modified chemical vapor deposition (CVD) process, called pulsed CVD, and the film properties were characterized as nucleation layers for a W-plug fill process. In this study, the deposition stage is composed of four steps, resulting in one deposition cycle: (i) reaction of WF6 with SiH4, (ii) inert gas purge, (iii) SiH4 exposure, and (iv) inert gas purge. The W growth per cycle was extremely linear with a growth rate of ∼ 1.32nm/cycle at 400°C. The growth rate was further enhanced to 1.5-1.9 nm/cycle by increasing the SiH4 flow rate in the first step and/or by adding H2 in the first and the third steps. The W film deposited by pulsed CVD showed a much lower roughness (∼0.7 nm) and a better conformality at the contact holes with an aspect ratio of 14, compared to W films deposited by conventional CVD using WF6 and SiH4. The film resistivity was closely related with its phase (body-centered cubic α-W or primitive cubic β-W) and microstructure characterized by grain size as well as the film thickness (the "size effect"). Transmission electron microscopy analysis showed that H2 addition into the first and third steps increased the grain size from ∼7 to ∼13 nm and prevented the film from forming a β-W phase with high resistivity, resulting in a lower resistivity of 100 μΩ-cm compared to that of the W film deposited without H2 addition (210 μΩ-cm). H2 addition was also effective in reducing the F and Si impurities in the films. Finally, the film resistivity was discussed on the basis of impurity, roughness, microstructure, and film phase.

Original languageEnglish
Pages (from-to)C408-C417
JournalJournal of the Electrochemical Society
Volume152
Issue number6
DOIs
Publication statusPublished - 2005 Aug 1

Fingerprint

Tungsten
Aspect ratio
Vapors
Thin films
Chemical vapor deposition
Noble Gases
Inert gases
Surface roughness
Impurities
Microstructure
Film thickness
Nucleation
Flow rate
Transmission electron microscopy

All Science Journal Classification (ASJC) codes

  • Electronic, Optical and Magnetic Materials
  • Renewable Energy, Sustainability and the Environment
  • Surfaces, Coatings and Films
  • Electrochemistry
  • Materials Chemistry

Cite this

Kim, Soo Hyun ; Hwang, Eui Sung ; Ha, Seung Chul ; Pyi, Seung Ho ; Sun, Ho Jung ; Lee, Joo Wan ; Kawk, Nohjung ; Kim, Jun Ki ; Sohn, Hyunchul ; Kim, Jinwoong. / Characterizations of pulsed chemical vapor deposited-tungsten thin films for ultrahigh aspect ratio W-plug process. In: Journal of the Electrochemical Society. 2005 ; Vol. 152, No. 6. pp. C408-C417.
@article{bac5e0be256d43aa9b7849509f2e17b9,
title = "Characterizations of pulsed chemical vapor deposited-tungsten thin films for ultrahigh aspect ratio W-plug process",
abstract = "Tungsten (W) thin films were deposited using a modified chemical vapor deposition (CVD) process, called pulsed CVD, and the film properties were characterized as nucleation layers for a W-plug fill process. In this study, the deposition stage is composed of four steps, resulting in one deposition cycle: (i) reaction of WF6 with SiH4, (ii) inert gas purge, (iii) SiH4 exposure, and (iv) inert gas purge. The W growth per cycle was extremely linear with a growth rate of ∼ 1.32nm/cycle at 400°C. The growth rate was further enhanced to 1.5-1.9 nm/cycle by increasing the SiH4 flow rate in the first step and/or by adding H2 in the first and the third steps. The W film deposited by pulsed CVD showed a much lower roughness (∼0.7 nm) and a better conformality at the contact holes with an aspect ratio of 14, compared to W films deposited by conventional CVD using WF6 and SiH4. The film resistivity was closely related with its phase (body-centered cubic α-W or primitive cubic β-W) and microstructure characterized by grain size as well as the film thickness (the {"}size effect{"}). Transmission electron microscopy analysis showed that H2 addition into the first and third steps increased the grain size from ∼7 to ∼13 nm and prevented the film from forming a β-W phase with high resistivity, resulting in a lower resistivity of 100 μΩ-cm compared to that of the W film deposited without H2 addition (210 μΩ-cm). H2 addition was also effective in reducing the F and Si impurities in the films. Finally, the film resistivity was discussed on the basis of impurity, roughness, microstructure, and film phase.",
author = "Kim, {Soo Hyun} and Hwang, {Eui Sung} and Ha, {Seung Chul} and Pyi, {Seung Ho} and Sun, {Ho Jung} and Lee, {Joo Wan} and Nohjung Kawk and Kim, {Jun Ki} and Hyunchul Sohn and Jinwoong Kim",
year = "2005",
month = "8",
day = "1",
doi = "10.1149/1.1897355",
language = "English",
volume = "152",
pages = "C408--C417",
journal = "Journal of the Electrochemical Society",
issn = "0013-4651",
publisher = "Electrochemical Society, Inc.",
number = "6",

}

Characterizations of pulsed chemical vapor deposited-tungsten thin films for ultrahigh aspect ratio W-plug process. / Kim, Soo Hyun; Hwang, Eui Sung; Ha, Seung Chul; Pyi, Seung Ho; Sun, Ho Jung; Lee, Joo Wan; Kawk, Nohjung; Kim, Jun Ki; Sohn, Hyunchul; Kim, Jinwoong.

In: Journal of the Electrochemical Society, Vol. 152, No. 6, 01.08.2005, p. C408-C417.

Research output: Contribution to journalArticle

TY - JOUR

T1 - Characterizations of pulsed chemical vapor deposited-tungsten thin films for ultrahigh aspect ratio W-plug process

AU - Kim, Soo Hyun

AU - Hwang, Eui Sung

AU - Ha, Seung Chul

AU - Pyi, Seung Ho

AU - Sun, Ho Jung

AU - Lee, Joo Wan

AU - Kawk, Nohjung

AU - Kim, Jun Ki

AU - Sohn, Hyunchul

AU - Kim, Jinwoong

PY - 2005/8/1

Y1 - 2005/8/1

N2 - Tungsten (W) thin films were deposited using a modified chemical vapor deposition (CVD) process, called pulsed CVD, and the film properties were characterized as nucleation layers for a W-plug fill process. In this study, the deposition stage is composed of four steps, resulting in one deposition cycle: (i) reaction of WF6 with SiH4, (ii) inert gas purge, (iii) SiH4 exposure, and (iv) inert gas purge. The W growth per cycle was extremely linear with a growth rate of ∼ 1.32nm/cycle at 400°C. The growth rate was further enhanced to 1.5-1.9 nm/cycle by increasing the SiH4 flow rate in the first step and/or by adding H2 in the first and the third steps. The W film deposited by pulsed CVD showed a much lower roughness (∼0.7 nm) and a better conformality at the contact holes with an aspect ratio of 14, compared to W films deposited by conventional CVD using WF6 and SiH4. The film resistivity was closely related with its phase (body-centered cubic α-W or primitive cubic β-W) and microstructure characterized by grain size as well as the film thickness (the "size effect"). Transmission electron microscopy analysis showed that H2 addition into the first and third steps increased the grain size from ∼7 to ∼13 nm and prevented the film from forming a β-W phase with high resistivity, resulting in a lower resistivity of 100 μΩ-cm compared to that of the W film deposited without H2 addition (210 μΩ-cm). H2 addition was also effective in reducing the F and Si impurities in the films. Finally, the film resistivity was discussed on the basis of impurity, roughness, microstructure, and film phase.

AB - Tungsten (W) thin films were deposited using a modified chemical vapor deposition (CVD) process, called pulsed CVD, and the film properties were characterized as nucleation layers for a W-plug fill process. In this study, the deposition stage is composed of four steps, resulting in one deposition cycle: (i) reaction of WF6 with SiH4, (ii) inert gas purge, (iii) SiH4 exposure, and (iv) inert gas purge. The W growth per cycle was extremely linear with a growth rate of ∼ 1.32nm/cycle at 400°C. The growth rate was further enhanced to 1.5-1.9 nm/cycle by increasing the SiH4 flow rate in the first step and/or by adding H2 in the first and the third steps. The W film deposited by pulsed CVD showed a much lower roughness (∼0.7 nm) and a better conformality at the contact holes with an aspect ratio of 14, compared to W films deposited by conventional CVD using WF6 and SiH4. The film resistivity was closely related with its phase (body-centered cubic α-W or primitive cubic β-W) and microstructure characterized by grain size as well as the film thickness (the "size effect"). Transmission electron microscopy analysis showed that H2 addition into the first and third steps increased the grain size from ∼7 to ∼13 nm and prevented the film from forming a β-W phase with high resistivity, resulting in a lower resistivity of 100 μΩ-cm compared to that of the W film deposited without H2 addition (210 μΩ-cm). H2 addition was also effective in reducing the F and Si impurities in the films. Finally, the film resistivity was discussed on the basis of impurity, roughness, microstructure, and film phase.

UR - http://www.scopus.com/inward/record.url?scp=22544438454&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=22544438454&partnerID=8YFLogxK

U2 - 10.1149/1.1897355

DO - 10.1149/1.1897355

M3 - Article

AN - SCOPUS:22544438454

VL - 152

SP - C408-C417

JO - Journal of the Electrochemical Society

JF - Journal of the Electrochemical Society

SN - 0013-4651

IS - 6

ER -