Improved Initial Growth Behavior of SrO and SrTiO3 Films Grown by Atomic Layer Deposition Using {Sr(demamp)(tmhd)}2 as Sr-Precursor

Woongkyu Lee; Woojin Jeon; Cheol Hyun An; Min Jung Chung; Han Joon Kim; Taeyong Eom; Sheby Mary George; Bo Keun Park; Jeong Hwan Han; Chang Gyoun Kim; Taek Mo Chung; Sang Woon Lee; Cheol Seong Hwang

doi:10.1021/acs.chemmater.5b00843

Improved Initial Growth Behavior of SrO and SrTiO₃ Films Grown by Atomic Layer Deposition Using {Sr(demamp)(tmhd)}₂ as Sr-Precursor

Woongkyu Lee, Woojin Jeon, Cheol Hyun An, Min Jung Chung, Han Joon Kim, Taeyong Eom, Sheby Mary George, Bo Keun Park, Jeong Hwan Han, Chang Gyoun Kim, Taek Mo Chung, Sang Woon Lee, Cheol Seong Hwang

Dept. of Materials Science & Engineering

Research output: Contribution to journal › Article › peer-review

46 Scopus citations

Abstract

An atomic layer deposition (ALD) process for SrTiO₃ (STO) thin film growth was developed using a newly designed and synthesized heteroleptic Sr-precursor, {Sr(demamp)(tmhd)}₂ (demampH = 1-{[2-(dimethylamino)ethyl](methyl)amino}-2-methylpropan-2-ol, tmhdH = 2,2,6,6-tetramethyl-3,5-heptanedione), which offered an intermediate reactivity toward oxygen between Sr(tmhd)₂ and Sr(ⁱPr₃Cp)₂. Because of the appropriate reactivity of {Sr(demamp)(tmhd)}₂ toward oxygen, the abnormal initial growth behavior (due to interaction between the Sr-precursor and active oxygen contained in the underlying oxidized Ru layer) became negligible during the growth of the SrO and STO films on the Ru electrode, which allowed the growth of the SrO and STO films to be highly controllable with a moderate growth rate. Using Ti(CpMe₅)(OMe)₃ as the Ti-precursor and O₃ as the oxygen source in the TiO₂ ALD subcycle, the ALD process of the STO film revealed a growth rate of 0.05 nm/cycle and ∼85% of step coverage in terms of the thickness and cation composition on a capacitor hole structure with an aspect ratio of 10 (opening diameter of 100 nm and depth of 1 μm). The minimum achievable equivalent oxide thickness (t_ox) with a low leakage current (<10^-7 A/cm² at 0.8 V) was limited to 0.46 nm. The damage effect on the underlying Ru electrode by the prolonged ALD process time appears to affect the limited scalability of t_ox.

Original language	English
Pages (from-to)	3881-3891
Number of pages	11
Journal	Chemistry of Materials
Volume	27
Issue number	11
DOIs	https://doi.org/10.1021/acs.chemmater.5b00843
State	Published - 9 Jun 2015

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Lee, W., Jeon, W., An, C. H., Chung, M. J., Kim, H. J., Eom, T., George, S. M., Park, B. K., Han, J. H., Kim, C. G., Chung, T. M., Lee, S. W., & Hwang, C. S. (2015). Improved Initial Growth Behavior of SrO and SrTiO₃ Films Grown by Atomic Layer Deposition Using {Sr(demamp)(tmhd)}₂ as Sr-Precursor. Chemistry of Materials, 27(11), 3881-3891. https://doi.org/10.1021/acs.chemmater.5b00843

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title = "Improved Initial Growth Behavior of SrO and SrTiO3 Films Grown by Atomic Layer Deposition Using \{Sr(demamp)(tmhd)\}2 as Sr-Precursor",

abstract = "An atomic layer deposition (ALD) process for SrTiO3 (STO) thin film growth was developed using a newly designed and synthesized heteroleptic Sr-precursor, \{Sr(demamp)(tmhd)\}2 (demampH = 1-\{[2-(dimethylamino)ethyl](methyl)amino\}-2-methylpropan-2-ol, tmhdH = 2,2,6,6-tetramethyl-3,5-heptanedione), which offered an intermediate reactivity toward oxygen between Sr(tmhd)2 and Sr(iPr3Cp)2. Because of the appropriate reactivity of \{Sr(demamp)(tmhd)\}2 toward oxygen, the abnormal initial growth behavior (due to interaction between the Sr-precursor and active oxygen contained in the underlying oxidized Ru layer) became negligible during the growth of the SrO and STO films on the Ru electrode, which allowed the growth of the SrO and STO films to be highly controllable with a moderate growth rate. Using Ti(CpMe5)(OMe)3 as the Ti-precursor and O3 as the oxygen source in the TiO2 ALD subcycle, the ALD process of the STO film revealed a growth rate of 0.05 nm/cycle and ∼85\% of step coverage in terms of the thickness and cation composition on a capacitor hole structure with an aspect ratio of 10 (opening diameter of 100 nm and depth of 1 μm). The minimum achievable equivalent oxide thickness (tox) with a low leakage current (<10-7 A/cm2 at 0.8 V) was limited to 0.46 nm. The damage effect on the underlying Ru electrode by the prolonged ALD process time appears to affect the limited scalability of tox.",

author = "Woongkyu Lee and Woojin Jeon and An, \{Cheol Hyun\} and Chung, \{Min Jung\} and Kim, \{Han Joon\} and Taeyong Eom and George, \{Sheby Mary\} and Park, \{Bo Keun\} and Han, \{Jeong Hwan\} and Kim, \{Chang Gyoun\} and Chung, \{Taek Mo\} and Lee, \{Sang Woon\} and Hwang, \{Cheol Seong\}",

note = "Publisher Copyright: {\textcopyright} 2015 American Chemical Society.",

year = "2015",

month = jun,

day = "9",

doi = "10.1021/acs.chemmater.5b00843",

language = "English",

volume = "27",

pages = "3881--3891",

journal = "Chemistry of Materials",

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T1 - Improved Initial Growth Behavior of SrO and SrTiO3 Films Grown by Atomic Layer Deposition Using {Sr(demamp)(tmhd)}2 as Sr-Precursor

AU - Lee, Woongkyu

AU - Jeon, Woojin

AU - An, Cheol Hyun

AU - Chung, Min Jung

AU - Kim, Han Joon

AU - Eom, Taeyong

AU - George, Sheby Mary

AU - Park, Bo Keun

AU - Han, Jeong Hwan

AU - Kim, Chang Gyoun

AU - Chung, Taek Mo

AU - Lee, Sang Woon

AU - Hwang, Cheol Seong

PY - 2015/6/9

Y1 - 2015/6/9

N2 - An atomic layer deposition (ALD) process for SrTiO3 (STO) thin film growth was developed using a newly designed and synthesized heteroleptic Sr-precursor, {Sr(demamp)(tmhd)}2 (demampH = 1-{[2-(dimethylamino)ethyl](methyl)amino}-2-methylpropan-2-ol, tmhdH = 2,2,6,6-tetramethyl-3,5-heptanedione), which offered an intermediate reactivity toward oxygen between Sr(tmhd)2 and Sr(iPr3Cp)2. Because of the appropriate reactivity of {Sr(demamp)(tmhd)}2 toward oxygen, the abnormal initial growth behavior (due to interaction between the Sr-precursor and active oxygen contained in the underlying oxidized Ru layer) became negligible during the growth of the SrO and STO films on the Ru electrode, which allowed the growth of the SrO and STO films to be highly controllable with a moderate growth rate. Using Ti(CpMe5)(OMe)3 as the Ti-precursor and O3 as the oxygen source in the TiO2 ALD subcycle, the ALD process of the STO film revealed a growth rate of 0.05 nm/cycle and ∼85% of step coverage in terms of the thickness and cation composition on a capacitor hole structure with an aspect ratio of 10 (opening diameter of 100 nm and depth of 1 μm). The minimum achievable equivalent oxide thickness (tox) with a low leakage current (<10-7 A/cm2 at 0.8 V) was limited to 0.46 nm. The damage effect on the underlying Ru electrode by the prolonged ALD process time appears to affect the limited scalability of tox.

AB - An atomic layer deposition (ALD) process for SrTiO3 (STO) thin film growth was developed using a newly designed and synthesized heteroleptic Sr-precursor, {Sr(demamp)(tmhd)}2 (demampH = 1-{[2-(dimethylamino)ethyl](methyl)amino}-2-methylpropan-2-ol, tmhdH = 2,2,6,6-tetramethyl-3,5-heptanedione), which offered an intermediate reactivity toward oxygen between Sr(tmhd)2 and Sr(iPr3Cp)2. Because of the appropriate reactivity of {Sr(demamp)(tmhd)}2 toward oxygen, the abnormal initial growth behavior (due to interaction between the Sr-precursor and active oxygen contained in the underlying oxidized Ru layer) became negligible during the growth of the SrO and STO films on the Ru electrode, which allowed the growth of the SrO and STO films to be highly controllable with a moderate growth rate. Using Ti(CpMe5)(OMe)3 as the Ti-precursor and O3 as the oxygen source in the TiO2 ALD subcycle, the ALD process of the STO film revealed a growth rate of 0.05 nm/cycle and ∼85% of step coverage in terms of the thickness and cation composition on a capacitor hole structure with an aspect ratio of 10 (opening diameter of 100 nm and depth of 1 μm). The minimum achievable equivalent oxide thickness (tox) with a low leakage current (<10-7 A/cm2 at 0.8 V) was limited to 0.46 nm. The damage effect on the underlying Ru electrode by the prolonged ALD process time appears to affect the limited scalability of tox.

UR - https://www.scopus.com/pages/publications/84931287894

U2 - 10.1021/acs.chemmater.5b00843

DO - 10.1021/acs.chemmater.5b00843

M3 - Article

AN - SCOPUS:84931287894

SN - 0897-4756

VL - 27

SP - 3881

EP - 3891

JO - Chemistry of Materials

JF - Chemistry of Materials

IS - 11

ER -

Improved Initial Growth Behavior of SrO and SrTiO₃ Films Grown by Atomic Layer Deposition Using {Sr(demamp)(tmhd)}₂ as Sr-Precursor

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