Thin film processing is widely used for manufacturing semiconductor devices, displays, solar panels, tribological coatings, and optical filters. Thin films deposited by conventional physical and chemical vapor methods typically involve tradeoffs between film quality (e.g. crystallinity) and manufacturability (e.g. deposition rates and temperature). Ion sources can enhance conventional thin-film processes to achieve both high film quality and manufacturability. Ion sources are plasma generation devices that enable ion beams to interact with materials at the atomic level and result in dense and smooth coatings. Conventional ion sources have multiple limitations. The filament-type ion sources are vulnerable in reactive gases (e.g. O2), which are detrimental to the filaments. The racetrack-type ion sources can operate in reactive environment, but the ion beams lack focusing onto the processing area.
This work reports a single beam ion source that overcomes the limitations of the conventional ion sources. The benefits of the single beam ion source include:
- Focused single beam of ions generated without a filament.
- Widely tunable ion energies from 30 eV to 300 eV for optimal ion-surface interactions.
- Wide range of operation pressure from 1.5 mTorr to 500 mTorr, compatible with the widely used sputtering and chemical vapor depositions.
- Simple designs that result in long-term stable operation and easy to maintain.
Using the single beam ion source to assist magnetron sputtering deposition of indium-tin-oxide (ITO) thin films leads to ~50% lower sheet resistance and significantly reduced surface roughness. The unique characteristics of the single beam ion sources are expected to transform the manufacturing of high-quality and low-cost thin-film products, such as flat panel displays, computer chips, solar photovoltaic devices, and superhard diamond-like carbon coatings.