Ultralow-dielectric-constant amorphous boron nitride.

Area of Science:

• Materials Science
• Electrical Engineering
• Nanotechnology

Background:

• Scaling down electronic devices is hindered by resistance and capacitance delays in interconnects.
• Developing suitable dielectric materials with low dielectric constants (κ) and good thermal-mechanical stability for interconnect isolation is challenging.
• Existing low-κ materials fail to meet the stringent requirements for future high-performance electronics.

Purpose of the Study:

• To develop and characterize novel dielectric films for advanced semiconductor interconnects.
• To address the need for materials with ultralow κ values and excellent barrier properties.
• To meet the International Roadmap for Devices and Systems' goal of dielectrics with κ < 2 by 2028.

Main Methods:

• Fabrication of three-nanometre-thick amorphous boron nitride films.
• Measurement of dielectric constant (κ) at various frequencies (100 kHz and 1 MHz).
• Assessment of mechanical robustness, breakdown strength, and diffusion barrier properties using cross-sectional imaging.

Main Results:

• Amorphous boron nitride films exhibited ultralow κ values of 1.78 (at 100 kHz) and 1.16 (at 1 MHz).
• The films demonstrated high mechanical and electrical robustness with a breakdown strength of 7.3 MV/cm.
• Amorphous boron nitride effectively prevented cobalt diffusion into silicon, outperforming reference materials.

Conclusions:

• Amorphous boron nitride films possess excellent low-κ dielectric properties, making them suitable for next-generation electronics.
• The material's robustness and diffusion barrier capabilities address critical challenges in semiconductor interconnect technology.
• This advancement paves the way for miniaturized, high-performance electronic devices.