Sn/Pb ratio variation in spherical structures deposited on silicon surface using plasma focus

Area of Science:

• Materials Science
• Plasma Physics
• Surface Engineering

Background:

• Plasma focus devices offer unique plasma characteristics for material deposition.
• Silicon substrates can be heated by plasma ion bombardment during deposition processes.
• Controlling elemental ratios in thin films is crucial for various applications.

Purpose of the Study:

• To investigate the deposition of tin (Sn) and lead (Pb) on a silicon (Si) surface using a plasma focus device.
• To understand the influence of plasma-induced surface heating on elemental deposition.
• To analyze the factors affecting the ratio of Sn to Pb in the deposited film.

Main Methods:

• Utilized a plasma focus device for sputtering and deposition of Sn and Pb onto a Si substrate.
• Varied the substrate-anode distance to control surface heating.
• Analyzed the elemental composition and depth profiles of the deposited SnPb film.
• Examined the morphology of micro-spherical structures on the surface.

Main Results:

• Surface heating due to plasma ion bombardment significantly influenced Sn and Pb deposition.
• The ratio of Sn to Pb in the deposited film differed from the anode's original ratio.
• The Sn/Pb ratio varied with depth into the film and was affected by micro-spherical structures.
• Observed a competition between deposition and evaporation processes driven by surface heating.

Conclusions:

• Plasma focus deposition parameters, particularly substrate-anode distance, critically affect elemental composition.
• Surface heating is a key factor controlling the deposition-evaporation balance and thus the film's elemental ratio.
• The formation of microstructures influences the local elemental distribution in SnPb films on Si.