Nickel Electroless Plating: Adhesion Analysis for Mono-Type Crystalline Silicon Solar Cells

Area of Science:

• Materials Science
• Semiconductor Manufacturing
• Photovoltaics

Background:

• Front electrode adhesion to silicon is critical for solar cell efficiency.
• Nickel silicide formation improves mechanical, electrical, and diffusion barrier properties.
• Optimizing nickel plating processes is key for reliable solar cell fabrication.

Purpose of the Study:

• To investigate and compare the adhesion properties of one-step and two-step nickel electroless plating processes for front electrodes.
• To evaluate the impact of a two-step process involving an intermediate sintering step on adhesion.
• To analyze the adhesion strength using a peel force tester after copper contact deposition.

Main Methods:

• Utilized p-type mono-crystalline silicon wafers.
• Formed emitter using POCl3 diffusion and applied SiNx anti-reflection coating via PECVD.
• Opened SiNx passivation using laser ablation.
• Deposited nickel using one-step and two-step electroless plating.
• Performed adhesion testing with a peel force tester after copper contact deposition via light-induced plating (LIP).

Main Results:

• The two-step nickel plating process demonstrated superior adhesion compared to the one-step process.
• Nickel silicide formation was integral to improved adhesion and barrier properties.
• The study quantified adhesion differences between the two plating methods.

Conclusions:

• The two-step nickel electroless plating method offers enhanced front electrode adhesion on silicon substrates.
• This improved adhesion is vital for the long-term reliability and performance of photovoltaic devices.
• The findings provide valuable insights for optimizing solar cell manufacturing processes.