ATOMIC LAYER DEPOSITION FOR RF DEVICES
Field Application Engineer - Forge Nano
PROTECTING RF DEVICES WITH ATOMIC LAYER DEPOSITION
Radio frequency (RF) and power electronics are vital to an array of industries, from telecom and consumer electronics to transportation and energy distribution. As energy diversification and the prevalence of high-speed electronics continue to grow, RF and power electronics are expected to reach a global market of $36.6 billion by 2027. Extreme environments such as high temperatures, ultra-violet radiation, oxygen, salinity, and moisture are all threats that degrade and corrode active components causing early failure. Atomic layer deposition (ALD) has created substantial improvements to the reliability and performance of RF and power electronics. Using ALD as an encapsulation layer at the wafer level or as a final hermetic seal at the chip/module/PCB level has been shown to substantially improve electronic performance and lifetime. ALD layers enable longer lifetimes, higher performance and lower cost without adding the considerable mass gain and high temperature processing associated with conventional hermetic coatings.
ALD BENEFITS FOR RF DEVICES
- Hermetic sealing encapsulation layers with minimal thickness
- Pristine conformality in high-aspect ratio structures
- Ultra-low particle generation
- Low stress films
- Improved lifetime of circuits and PCBs
- Increased resistance to harsh environments
- No peeling or flaking of the hermetic seal at atmospheres >1200 PSI
- Negligible mass gain from coating at 100 nm
ALD TOOL BOX
One of the most important layers in post-gate processing for RF and power devices is the encapsulation layer to protect the device from environmental degradation. Thin encapsulation layers have found to decrease humidity permeation rates on moisture sensitive devices. In a study from April 2020, RF microelectronic mechanical devices (MEMs) were encapsulated with SiNx thin films for environmental protection on 5G devices and showed successful mechanical protection. Beyond environmental protection, encapsulation layers have also been found to improve RF device performance. One study showed encapsulated GaAs-based terahertz emitters increased the average power output fourfold by enhancing the conductivity and prevention oxidation at the semiconductor surface.
Due to application challenges in extreme environments, RF and power electronics require robust hermetic sealing to maintain reliability over conventional integrated circuits. Electronics demanding this extra layer of protection frequently use plastic to encapsulate circuits for added protection which creates additional weight and cost to the final product. In certain aerospace applications requiring military standards (MIL-STD), ceramic encapsulation provides more protection than plastic packaging yet requires higher temperature processing and adds significant weight to the final product.
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