Fabrication of thin silicon sheets for solar cells using the spin casting method.

Area of Science:

• Materials Science
• Manufacturing Engineering
• Semiconductor Processing

Background:

• Current silicon wafer production involves material loss due to sawing (kerf).
• Developing kerf-free wafer production methods is crucial for reducing silicon waste and cost.
• Spin casting offers a potential route for direct fabrication of thin silicon structures.

Purpose of the Study:

• Investigate spin casting for fabricating thin silicon sheets.
• Optimize the spin casting process for kerf-free wafer production.
• Understand the influence of process parameters on melt spreading and sheet formation.

Main Methods:

• Numerical simulation of the spin casting process to model melt dynamics.
• Experimental validation of simulation predictions using a rotating graphite mold.
• Systematic variation of initial droplet velocity and observation of melt spreading behavior.

Main Results:

• Simulation identified a critical initial droplet velocity for effective melt spreading.
• Experimental results confirmed the necessity of specific droplet velocities.
• Increased droplet velocity significantly reduced spreading time, preventing premature solidification.
• Achieved production of 100-micrometer thick silicon sheets under optimized conditions.

Conclusions:

• Spin casting is a viable method for producing thin silicon sheets.
• Precise control over initial droplet velocity is key to successful melt spreading and sheet formation.
• Optimized spin casting can contribute to efficient, kerf-free silicon wafer manufacturing.