Gas Diffusion Barriers Prepared by Spatial Atmospheric Pressure Plasma Enhanced ALD

Area of Science:

• Materials Science
• Thin Film Technology
• Surface Chemistry

Background:

• Gas permeation barriers are crucial for various applications, including electronics packaging and food preservation.
• Traditional methods for creating high-performance barriers often require high temperatures or vacuum conditions.
• Atmospheric pressure deposition techniques offer potential for cost-effective and scalable barrier fabrication.

Purpose of the Study:

• To investigate the preparation of aluminum oxide (Al2O3) gas permeation barriers using spatial atomic layer deposition (SALD) at atmospheric pressure.
• To compare the growth characteristics and layer properties of Al2O3 films deposited under varying conditions.
• To evaluate the barrier performance, specifically water vapor transmission rates (WVTR), of the fabricated Al2O3 films.

Main Methods:

• Aluminum oxide (Al2O3) films were deposited using spatial atomic layer deposition (SALD) at atmospheric pressure.
• Trimethylaluminum (TMA) and a remote atmospheric pressure Ar/O2 plasma were employed as precursors.
• Film properties were analyzed for different substrate velocities and deposition temperatures.
• Water vapor transmission rates (WVTR) were measured to assess barrier performance.

Main Results:

• Ultralow water vapor transmission rates (WVTR) on the order of 10^-6 g m^-2 d^-1 were achieved for Al2O3 films.
• Plasma-based deposition demonstrated good barrier properties at lower temperatures (75 °C).
• Water-based processes required higher temperatures (>100 °C) to attain comparable low WVTRs.
• The activation energy for the water permeation mechanism was determined to be 62 kJ/mol.

Conclusions:

• Spatial ALD at atmospheric pressure is a viable technique for producing high-performance Al2O3 gas permeation barriers.
• Plasma-enhanced SALD offers advantages for low-temperature barrier fabrication compared to water-based processes.
• The ultralow WVTR values indicate the potential of these Al2O3 films for demanding barrier applications.