Plasma enhanced magnetron sputtering (PEMS) for III-N materials on silicon substrates

Overview

Plasma Enhanced Magnetron Sputtering (PEMS) is an advanced deposition process developed by Southwest Research Institute, designed specifically for III-N materials on silicon substrates. Combining traditional magnetron sputtering with a secondary, independently controlled plasma, PEMS achieves higher deposition rates and enhanced morphology control. This capability is critical for materials like AlN and GaN, allowing for deposition at significantly lower temperatures (350-450°C), which mitigates issues related to the coefficient of thermal expansion mismatch between GaN and Si. PEMS is particularly beneficial for scaling to larger silicon wafer diameters, as it controls layer stresses during growth, enabling the deposition of thick nitride materials.

Technical specifications

• High deposition rates: PEMS surpasses advanced sputtering methods like HIPIMS in deposition efficiency.
• Independently controlled plasma: Allows for precise control over ionization away from the sputtering target, enhancing morphology and stress control.
• Lower deposition temperature: Operates at 350-450°C, compared to the 750°C and 900°C required for GaN and AlN respectively, in traditional methods.
• Scalability: Suitable for large silicon wafers, reducing wafer bow and stress during deposition, with potential for scaling equipment for larger area and higher throughput applications.

Technology readiness level

The technology is currently at TRL 6, indicating it has been demonstrated in a relevant environment. Future validation steps include optimizing AlN on Si(111) to further reduce deposition temperatures and assess scalability for larger wafer sizes. Further research could explore different III-N materials or equipment scaling based on specific application needs.