Impacts of plasma fluctuation on growth of nanoparticles in low pressure reactive VHF discharge plasmas

Here we discuss impacts of plasma fluctuation on nanostructure formation using plasmas. We studied the effects of plasma fluctuation on the growth of nanoparticles in capacitively-coupled VHF discharges with amplitude modulation (AM) using 2 dimensional laser light scattering method [1]. AM gives an artificial plasma fluctuation. Nanoparticles grow more slowly for higher AM levels, which causes the density of nanoparticles to increase by 100{\%}, their size to decrease by 23{\%}, and narrower size dispersion. The increase in the nucleation density of nanoparticles by AM causes a decrease in the radical flux to a nanoparticle. Eventually we obtained a diagram of the three particle growth modes of positive feedback, negative feedback, and independent ones. We also have developed a simple theory of particle growth in reactive plasmas. The theory predicts experimental results well. Our approach can be applied to realize precise control of a wide variety of nanostructure formations.\\[4pt] [1] K. Kamataki, et al., J. Inst. 7 (2012) C04017.