Despite its scarcity, gallium arsenide (GaAs) is crucial for several industries. Thanks to its unique electron mobility, many manufacturers depend on these wafers, often making the most of them and reutilizing GaAs reclaim wafers several times to optimize production.
One of these unique properties is its resistance to radioactivity, which enhances its performance in various applications and positions it as a preferred material in critical industries like solar energy, aerospace, and telecommunications. Here, we will explore why GaAs wafers exhibit such resistance to radioactivity and discuss the broader implications of their use.
Radioactivity is a process in which unstable atomic nuclei lose energy by emitting radiation. All matter is constantly bombarded with radiation from both cosmic and terrestrial sources. However, high radiation can damage semiconductor material structures, causing changes at the atomic level that affect structural integrity and electronic properties.
This energy can affect semiconductor materials in two ways:
Ionizing radiation is the most common cause of radiation damage in semiconductors. When a substrate material's atomic structure is struck by heavily charged alpha, beta, gamma, or neutrons, the orbital electrons are impacted, changing its electrical characteristics. This can affect the device's operation, including non-switching conditions, fluctuating values, lower voltage, and other temporary and permanent damages. The end result is degraded performance and a loss of reliability.
While all materials are affected by intense radiation over time, GaAs is a compound semiconductor whose crystalline structure can withstand extended periods of exposure. According to a 2018 study published in the Journal of Applied Physics, GaAs diodes maintained over 90% of their initial efficiency after being exposed to high doses of gamma radiation. In comparison, the efficiency of silicon devices dropped below 70%. There are several reasons why GaAs present enhanced registration against radioactivity:
Despite advancements in materials and substrates, silicon remains the backbone of the semiconductor industry—for most commercial applications, at least. Its availability makes it a go-to choice for most electrical devices and similar applications whose end target is the wider public.
However, in environments where radiation exposure is expected, GaAs is better, as silicon has inherent limitations when exposed to radiation.
Silicon devices, for example, can be damaged by displacement, which occurs when energetic particles displace atoms from their lattice positions, resulting in defects. This has an impact on silicon's electrical properties and reduces its overall reliability.
A comparative study published in the IEEE Transactions on Nuclear Science found that GaAs can withstand radiation levels that would cause significant degradation in silicon devices. Moreover, GaAs-based devices highly outperformed their silicon counterparts in terms of radiation tolerance.
Furthermore, GaAs solar cells can withstand radiation exposures of up to 50 krad (Si) in space environments, while silicon solar cells can typically withstand only 10–20 krad (Si) before experiencing noticeable degradation.
For GaAs devices in space missions, this means a longer operational lifetime.
In contrast to silicon, GaAs has better radiation hardness, which is crucial in settings like space, where radiation levels are much higher. Because of the high levels of cosmic radiation that satellites and other spacecraft must endure, dependable materials are crucial to the success of missions.
While silicon devices usually fail at much lower radiation doses, studies have shown that GaAs devices can withstand doses up to 100 krad (Si) without experiencing appreciable performance degradation. GaAs' resilience allows components to last longer in space, reducing the need for frequent replacements and ensuring mission safety.
This could result in lower overall mission costs and improve the feasibility of long-term space missions, such as those to Mars or beyond.
Moreover, GaAs solar cells also provide higher efficiency. For instance, GaAs solar cells can achieve efficiencies of over 30% under standard test conditions, while silicon cells typically max out around 22%. This efficiency translates to better power generation in space applications where sunlight is the primary energy source.
Cosmic radiation is a natural source of background radiation that originates in outer space. It’s composed of penetrating ionizing radiation caused by the sun and stars, which constantly stream cosmic radiation to Earth.
We are not affected thanks to differences in elevation, atmospheric conditions, and the Earth's magnetic field. The average individual only receives 45 to 50 millirem of background radiation caused by cosmic radiation. However, satellites and other aerospace devices aren’t that lucky, so utilizing radiation-resistant materials is key.
Reclaimed wafers are previously used wafers that have been processed to remove defects and restore surface properties, allowing them to be reused to manufacture new devices. While they offer several benefits and are cost-effective, they aren’t employed in the aerospace industry due to the demands of such a harsh environment.
Instead, military and aerospace-related manufacturers prefer to use virgin wafers to ensure the safety and durability of their devices.
.jpg)
GaAs wafers provide significant advantages over traditional materials such as silicon, particularly in terms of radiation resistance. This property is critical in applications requiring high reliability and performance, such as those in the aerospace industry and elsewhere.
As technology advances and the demand for durable electronic materials grows, GaAs will likely play an important role in shaping the future of high-performance electronics in radiation-sensitive environments. Here at Wafer World, we’re excited to see what’s to come. If you’re interested in learning more about gallium arsenide or would like to hear more about the applications of this substrate, contact us today!
