AAAR 34th Annual Conference
October 12 - October 16, 2015
Hyatt Regency
Minneapolis, Minnesota, USA
Abstract View
Pulsed Radio-Frequency Argon-Silane Plasmas for Controlled Deposition of Silicon Nanoparticles
CARLOS LARRIBA-ANDALUZ, Steven Girshick, University of Minnesota
Abstract Number: 24 Working Group: Nanoparticles and Materials Synthesis
Abstract Reactive plasmas are extensively used in the industry due to their ability to produce large amounts of reactive radicals and of energetic ions. When a nanoparticle precursor, such as silane is introduced into such systems, nanoparticles nucleate and grow in what is referred in literature as “nanodusty” plasmas. Recently, it has been hypothesized that plasma-enhanced deposition of Silicon nanoparticles can be a means to provide fully crystalline silicon films if the impact energy and size of the nanoparticles is accurately controlled to allow amorphization of the nanoparticle and subsequent recrystallization without damaging the substrate film. In order to achieve such conditions, here we numerically model an RF silane-containing plasma that is pulsed at a known frequency with the goal to provide suitable markers that will be used in the future as experimental guidelines. Among the possible testing parameters, one has several candidates, including RF voltage, pressure, pulsing frequency, duty cycle and DC bias voltage. This DC bias voltage is applied during the OFF phase of the pulsing to recollect nanoparticles and control their impact energies. This complex set of possible parameters is tested to maximize silicon film growth while maintaining the impact energy within the desired boundaries.
For such undertaking, we utilize a previously developed 1-D numerical model, modified to consider general chemistry, pulsing and applied substrate bias. This model self-consistently solves for the coupled behavior of plasma, chemistry, and aerosol. An aerosol sectional model is used to model the evolution of particle size and charge distributions which includes nucleation (rate of formation of anions containing three Si atoms is taken as a surrogate for the particle nucleation rate), surface growth, size and charge dependent coagulation, ion and electron attachment based on Orbital Motion Limited theory as well as ion drag and Brownian Diffusion.