Related Experiment Video
Updated: Aug 5, 2026
11:42
Fabrication of Gate-tunable Graphene Devices for Scanning Tunneling Microscopy Studies with Coulomb Impurities
Published on: July 24, 2015
Porous Ultralow-κ sp2-Bonded Boron Nitride Thin Films as Copper Diffusion Barriers
Caiyun Liu1, Ze Long1, Zhongyuan Han2
1State Key Laboratory of High Pressure and Superhard Materials, College of Physics, Jilin University, Changchun, People's Republic of China.
Advanced Science (Weinheim, Baden-Wurttemberg, Germany)
|July 30, 2026
Summary
Porous boron nitride (BN) films with an ultralow dielectric constant (κ) of 1.77 were developed. These materials offer excellent mechanical strength, hydrophobicity, and copper diffusion barrier properties for advanced microelectronics.
Area of Science:
- Materials Science
- Nanotechnology
- Microelectronics Engineering
Background:
- Decreasing microelectronic device sizes necessitate dielectric materials with a low dielectric constant (κ < 2).
- Introducing voids into dielectric materials reduces the dielectric constant but often compromises mechanical strength and wetting properties.
- Boron nitride (BN) is a promising material for dielectric applications due to its inherent properties.
Purpose of the Study:
- To develop porous sp2-bonded boron nitride (BN) films with an ultralow dielectric constant.
- To investigate the structural, electrical, and mechanical properties of these porous BN films.
- To evaluate their potential as diffusion barriers in microelectronic applications.
Main Methods:
- Radio frequency magnetron sputtering was used to grow porous BN films on silicon substrates.
- Grazing incidence small-angle X-ray scattering (GISAXS) and electron microscopy were employed to characterize pore structure.
- Dielectric properties, band gap, surface hydrophobicity, mechanical stability, and copper diffusion barrier capabilities were measured.
Main Results:
- Porous BN (p-BN) films with a pore size of approximately 1.85 nm were successfully synthesized.
- The p-BN films exhibited an ultralow dielectric constant (κ) of 1.77 at 100 kHz, a wide band gap (5.88 eV), and a hydrophobic surface.
- These films demonstrated excellent electrical robustness, mechanical stability comparable to dense BN, and effective copper diffusion barrier properties at a thickness of 3 nm.
Conclusions:
- Porous sp2-bonded BN films offer a viable solution for ultralow-κ dielectrics in high-performance electronics.
- The controlled synthesis of these films addresses challenges in mechanical strength and wetting properties associated with porous materials.
- Their multifunctional capabilities make them suitable for applications such as transistor gate dielectrics, passivation layers, and capacitor spacers.
