Array of Graphene Variable Capacitors on 100 mm Silicon Wafers for Vibration-Based Applications

Area of Science:

• Materials Science
• Electrical Engineering
• Nanotechnology

Background:

• Freestanding graphene membranes offer high flexibility and electrical conductivity, making them suitable for vibration-based applications.
• Integrating novel materials like graphene into existing semiconductor manufacturing processes is crucial for technological advancement.

Purpose of the Study:

• To develop a scalable semiconductor manufacturing method for fabricating freestanding graphene-based variable capacitors.
• To demonstrate the integration of graphene membranes into mainstream silicon wafer fabrication.

Main Methods:

• A two-mask lithography process was designed and implemented on 100 mm silicon wafers.
• The process involves creating trenches with specific well structures and fabricating metal traces for electrical contacts.
• Graphene membranes were suspended over wells to form variable capacitors, with additional fabrication on integrated circuit dies.

Main Results:

• An array of freestanding graphene-based variable capacitors was successfully fabricated on silicon wafers.
• Capacitor structures were also successfully fabricated on bare dies with underlying integrated circuits.
• Characterization included atomic force microscopy, optical microscopy, and time-dependent capacitance measurements.

Conclusions:

• The developed two-mask lithography process is effective for integrating graphene membranes into semiconductor manufacturing.
• This work paves the way for scalable production of flexible, conductive graphene-based electronic components.
• The fabricated variable capacitors show potential for advanced vibration-based sensing and energy harvesting applications.