Saima Ali

Dr. Saima Ali

orcid

Research Focus & Metrics

Academic Career Length

14Years (2013-Present)

(Calculated once Scilit publication data is synced: current year − year of first publication + 1)

Representative Publications

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1 February 2014 in Thin Solid Films
Verified
Journal Article
Closed access
OYOili M.E. Ylivaara
Oili M.E. Ylivaara
XLXuwen Liu
Xuwen Liu
LKLauri Kilpi
Lauri Kilpi
JLJussi Lyytinen
Jussi Lyytinen
DSDieter Schneider
Dieter Schneider
RPRiikka L. Puurunen
Riikka L. Puurunen

16 December 2016 in Journal of Vacuum Science & Technology A
Verified
Journal Article
Open access
PDF file
EAEsko Ahvenniemi
Esko Ahvenniemi
AAAndrew R. Akbashev
Andrew R. Akbashev
SASaima Ali
Saima Ali
Mikhael BECHELANYMikhael BECHELANY
Mikhael BECHELANY
MBMaria Berdova
Maria Berdova
OYOksana Yurkevich
Oksana Yurkevich
Atomic layer deposition (ALD), a gas-phase thin film deposition technique based on repeated, self-terminating gas–solid reactions, has become the method of choice in semiconductor manufacturing and many other technological areas for depositing thin conformal inorganic material layers for various applications. ALD has been discovered and developed independently, at least twice, under different names: atomic layer epitaxy (ALE) and molecular layering. ALE, dating back to 1974 in Finland, has been commonly known as the origin of ALD, while work done since the 1960s in the Soviet Union under the name “molecular layering” (and sometimes other names) has remained much less known. The virtual project on the history of ALD (VPHA) is a volunteer-based effort with open participation, set up to make the early days of ALD more transparent. In VPHA, started in July 2013, the target is to list, read and comment on all early ALD academic and patent literature up to 1986. VPHA has resulted in two essays and several presentations at international conferences. This paper, based on a poster presentation at the 16th International Conference on Atomic Layer Deposition in Dublin, Ireland, 2016, presents a recommended reading list of early ALD publications, created collectively by the VPHA participants through voting. The list contains 22 publications from Finland, Japan, Soviet Union, United Kingdom, and United States. Up to now, a balanced overview regarding the early history of ALD has been missing; the current list is an attempt to remedy this deficiency.

1 May 2014 in Thin Solid Films
Verified
Journal Article
Closed access
MPMatti Putkonen
Matti Putkonen
MBMarkus Bosund
Markus Bosund
OYOili M.E. Ylivaara
Oili M.E. Ylivaara
RPRiikka L. Puurunen
Riikka L. Puurunen
LKLauri Kilpi
Lauri Kilpi
MVMika Vähä-Nissi
Mika Vähä-Nissi

4 November 2016 in Journal of Vacuum Science & Technology A
Verified
Journal Article
Closed access
PDF file
OYOili M. E. Ylivaara
Oili M. E. Ylivaara
LKLauri Kilpi
Lauri Kilpi
XLXuwen Liu
Xuwen Liu
SSSakari Sintonen
Sakari Sintonen
SASaima Ali
Saima Ali
RPRiikka L. Puurunen
Riikka L. Puurunen
Atomic layer deposition (ALD) is based on self-limiting surface reactions. This and cyclic process enable the growth of conformal thin films with precise thickness control and sharp interfaces. A multilayered thin film, which is nanolaminate, can be grown using ALD with tuneable electrical and optical properties to be exploited, for example, in the microelectromechanical systems. In this work, the tunability of the residual stress, adhesion, and mechanical properties of the ALD nanolaminates composed of aluminum oxide (Al2O3) and titanium dioxide (TiO2) films on silicon were explored as a function of growth temperature (110–300 °C), film thickness (20–300 nm), bilayer thickness (0.1–100 nm), and TiO2 content (0%–100%). Al2O3 was grown from Me3Al and H2O, and TiO2 from TiCl4 and H2O. According to wafer curvature measurements, Al2O3/TiO2 nanolaminates were under tensile stress; bilayer thickness and growth temperature were the major parameters affecting the stress; the residual stress decreased with increasing bilayer thickness and ALD temperature. Hardness increased with increasing ALD temperature and decreased with increasing TiO2 fraction. Contact modulus remained approximately stable. The adhesion of the nanolaminate film was good on silicon.

5 January 2018 in Materials
Verified
Journal Article
Open access
PDF file
HGHenrika Granbohm
Henrika Granbohm
JLJuha Larismaa
Juha Larismaa
SASaima Ali
Saima Ali
LJLeena-Sisko Johansson
Leena-Sisko Johansson
SHSimo-Pekka Hannula
Simo-Pekka Hannula
The growth of silver nanoparticles, the activation energy for silver particle growth, and the release of silver species in heat treated SiO 2 -Ag composite powders are investigated. The silver particle growth is controlled by heat treatment for 75 min of the as-synthesized SiO 2 -Ag composite powder at 300–800 °C. During heat treatment the mean size of the Ag particles increases from 10 nm up to 61 nm with increasing temperature, however, the particle size distribution widens and the mean size increases with increasing heat treatment temperature. Based on X-ray photoelectron spectroscopy (XPS) and transmission electron microscopy (TEM) studies, silver particles are crystalline and in a metallic state after annealing in all SiO 2 -Ag composite powders. The growth of Ag particles is suggested to take place via diffusion and Ostwald ripening. The activation energy for particle growth was determined as 0.14 eV. The dissolution of silver in aqueous solutions from the SiO 2 -Ag composites heat treated, at 300 °C, 600 °C, and 700 °C, was investigated by varying pH and temperature. The dissolution was reduced in all conditions with increasing silver particle size, i.e., when the total surface area of Ag particles is reduced. It is suggested that the dissolution of silver from the composite powders can conveniently be adjusted by controlling the Ag particle size by the heat treatment of the composite powder.

1 August 2021 in Thin Solid Films
Verified
Journal Article
Open access
OYOili M.E. Ylivaara
Oili M.E. Ylivaara
ALAndreas Langner
Andreas Langner
XLXuwen Liu
Xuwen Liu
DSDieter Schneider
Dieter Schneider
JJJaakko Julin
Jaakko Julin
RPRiikka L. Puurunen
Riikka L. Puurunen