1 research outputs found
A Systematic Study of Plasma Activation of Silicon Surfaces for Self Assembly
We study the plasma activation systematically
in an attempt to simplify and optimize the formation of hydrophilic
silicon (Si) surface critical for self-assembly of nanostructures
that typically uses <i>piranha</i> solution, a high molarity
cocktail of sulfuric acid and hydrogen peroxide at elevated temperatures.
In the proposed safer and simpler approach, O<sub>2</sub> plasma is
used under optimized process conditions in a capacitively coupled
parallel-plate chamber to induce strong hydrophilic behavior on silicon
surfaces associated with the formation of suboxide groups. Surface
activation is validated and studied via contact angle measurements
as well as XPS spectra and consequently optimized using a novel atomic
force spectroscopy approach, which can streamline characterization.
It is found that plasma power around 100 W and exposure duration of
∼65 s are the most effective parameters to enhance surface
activation for the reactive ion etcher system used. Other optimum
plasma process conditions for pressure and flow-rate are also reported
along with temporal development of activation, which peaks within
1 h and wears off in 24 h scale in air. The applicability of the plasma
approach to nanoassembly process was demonstrated using simple drop
coating and spinning of polystyrene (<i>d</i> < 500 nm,
2.5–4.5% w/v) and inkjet printing on polydimethylsiloxane