Low- k SiOx/AlOx Nanolaminate Dielectric on Dielectric Achieved by Hybrid Pulsed Chemical Vapor Deposition

James Huang; Jing Mu; Yunil Cho; Charles Winter; Victor Wang; Zichen Zhang; Kesong Wang; Chanyoung Kim; Ajay Yadav; Keith Wong; Srinivas Nemani; Ellie Yieh; Andrew Kummel

doi:10.1021/acsami.3c13973

Low- k SiO_x/AlO_x Nanolaminate Dielectric on Dielectric Achieved by Hybrid Pulsed Chemical Vapor Deposition

ACS Appl Mater Interfaces. 2023 Dec 6;15(48):56556-56566. doi: 10.1021/acsami.3c13973. Epub 2023 Nov 18.

Authors

James Huang¹, Jing Mu¹, Yunil Cho², Charles Winter³, Victor Wang¹, Zichen Zhang¹, Kesong Wang⁴, Chanyoung Kim⁵, Ajay Yadav⁶, Keith Wong⁶, Srinivas Nemani⁶, Ellie Yieh⁶, Andrew Kummel⁷

Affiliations

¹ Program in Materials Science and Engineering, University of California, San Diego, La Jolla, California 92093, United States.
² Department of Electrical and Computer Engineering, University of California, San Diego, La Jolla, California 92093, United States.
³ Department of Chemistry, Wayne State University, Detroit, Michigan 48202, United States.
⁴ Department of Mechanical and Aerospace Engineering, University of California, San Diego, La Jolla, California 92093, United States.
⁵ Department of Nanoengineering, University of California, San Diego, La Jolla, California 92093, United States.
⁶ Applied Materials, Inc., Santa Clara, California 95054, United States.
⁷ Department of Chemistry and Biochemistry, University of California, San Diego, La Jolla, California 92093, United States.

PMID: 37978920
DOI: 10.1021/acsami.3c13973

Abstract

Selective and smooth low-k SiO_x/AlO_x nanolaminate dielectric on dielectric (DOD) was achieved by a hybrid water-free pulsed CVD process consisting of 50 pulses of ATSB (tris(2-butoxy)aluminum) at 330 °C and a 60 s TBS (tris(tert-butoxy)silanol) exposure at 200 °C. Aniline selective passivation was demonstrated on W surfaces in preference to Si₃N₄ and SiO₂ at 300 °C. At 200 °C, TBS pulsed CVD exhibited no growth on W or SiO₂, but its growth was catalyzed by AlO_x. Using a two-temperature pulsed CVD process, ∼2.7 nm selective SiO_x/AlO_x nanolaminate was deposited on Si₃N₄ in preference to aniline passivated W. Nanoselectivity was confirmed and demonstrated on nanoscale W/SiO₂ patterned samples by TEM analysis. For a 1:1 Si:Al ratio, a dielectric constant (k) value of 3.3 was measured. For a 2:1 Si:Al ratio, a dielectric constant (k) value of 2.5 was measured. The k value well below that of Al₂O₃ and SiO₂ is consistent with the formation of a low-density, low-k SiO₂/Al₂O₃ nanolaminate in a purely thermal process. This is the first report of a further thermal CVD process for deposition of a low-k dielectric and the first report for a selective low-k process on the nanoscale.

Keywords: AlOx; SiOx; dielectric on dielectric; low-k dielectric; nanolaminate; selective CVD.