Electronics That Defy Venus’ Heat: How Gallium Nitride Could Revolutionize Space Exploration

High Temperatures Electronic Devices Made From Gallium Nitride

Researchers studied how temperatures up to 500 degrees Celsius would affect electronic devices made from gallium nitride, a key step in their multiyear research effort to develop electronics that can operate in extremely hot environments, like the surface of Venus. Credit: MIT News; iStock

Researchers are turning to gallium nitride for high-temperature applications such as <span class="glossaryLink" aria-describedby="tt" data-cmtooltip="

Venus, the second planet from the sun, is named after the Roman goddess of love and beauty. After the moon, it is the second-brightest natural object in the night sky. Its rotation (243 Earth days) takes longer than its orbit of the Sun (224.7 Earth days). It is sometimes called Earth's &quot;sister planet&quot; because of their similar composition, size, mass, and proximity to the Sun. It has no natural satellites.

” data-gt-translate-attributes=”[{"attribute":"data-cmtooltip", "format":"html"}]” tabindex=”0″ role=”link”>Venus exploration, due to its ability to withstand temperatures above 500 degrees <span class="glossaryLink" aria-describedby="tt" data-cmtooltip="

The Celsius scale, also known as the centigrade scale, is a temperature scale named after the Swedish astronomer Anders Celsius. In the Celsius scale, 0 °C is the freezing point of water and 100 °C is the boiling point of water at 1 atm pressure.

” data-gt-translate-attributes=”[{"attribute":"data-cmtooltip", "format":"html"}]” tabindex=”0″ role=”link”>Celsius.

A recent study by <span class="glossaryLink" aria-describedby="tt" data-cmtooltip="

MIT is an acronym for the Massachusetts Institute of Technology. It is a prestigious private research university in Cambridge, Massachusetts that was founded in 1861. It is organized into five Schools: architecture and planning; engineering; humanities, arts, and social sciences; management; and science. MIT's impact includes many scientific breakthroughs and technological advances. Their stated goal is to make a better world through education, research, and innovation.

” data-gt-translate-attributes=”[{"attribute":"data-cmtooltip", "format":"html"}]” tabindex=”0″ role=”link”>MIT and other institutions has shown that this material, along with its ohmic contacts, remains structurally stable even at these high temperatures. The study involved building gallium nitride devices and testing them under high-temperature conditions, revealing promising results for future electronics in extreme environments.

Venus Exploration and Gallium Nitride

On the scorching surface of Venus, temperatures can climb to 480° Celsius /900° <span class="glossaryLink" aria-describedby="tt" data-cmtooltip="

The Fahrenheit scale is a temperature scale, named after the German physicist Daniel Gabriel Fahrenheit and based on one he proposed in 1724. In the Fahrenheit temperature scale, the freezing point of water freezes is 32 °F and water boils at 212 °F, a 180 °F separation, as defined at sea level and standard atmospheric pressure.&nbsp;

” data-gt-translate-attributes=”[{"attribute":"data-cmtooltip", "format":"html"}]” tabindex=”0″ role=”link”>Fahrenheit, which is hot enough to melt lead. This makes it an inhospitable place for humans and machines alike. One reason scientists have not yet been able to send a rover to the planet’s surface is that silicon-based electronics can’t operate in such extreme temperatures for an extended period of time.

For high-temperature applications like Venus exploration, researchers have recently turned to gallium nitride, a unique material that can withstand temperatures of 500 degrees or more.

The material is already used in some terrestrial electronics, like phone chargers and cell phone towers, but scientists don’t have a good grasp of how gallium nitride devices would behave at temperatures beyond 300 degrees, which is the operational limit of conventional silicon electronics.

Research Findings on Gallium Nitride

In a new paper published in <span class="glossaryLink" aria-describedby="tt" data-cmtooltip="

Applied Physics Letters
&lt;em&gt;Applied Physics Letters (APL)&lt;/em&gt; is a weekly peer-reviewed scientific journal that publishes brief articles on significant new findings in applied physics. Established in 1962, the journal is managed by the American Institute of Physics. It covers a broad spectrum of topics in applied physics, including electronics, photonics, materials science, and applications of physics in biology and medicine. The articles are concise, focusing on the impact and immediate implications of the research rather than exhaustive details, making them accessible to a broad scientific audience. This format and approach help facilitate rapid dissemination of cutting-edge research findings within the scientific community.

” data-gt-translate-attributes=”[{"attribute":"data-cmtooltip", "format":"html"}]” tabindex=”0″ role=”link”>Applied Physics Letters, which is part of a multiyear research effort, a team of scientists from MIT and elsewhere sought to answer key questions about the material’s properties and performance at extremely high temperatures.


They studied the impact of temperature on the ohmic contacts in a gallium nitride device. Ohmic contacts are key components that connect a semiconductor device with the outside world.

The researchers found that extreme temperatures didn’t cause significant degradation to the gallium nitride material or contacts. They were surprised to see that the contacts remained structurally intact even when held at 500 degrees Celsius for 48 hours.

Future Directions in High-Temperature Electronics

Understanding how contacts perform at extreme temperatures is an important step toward the group’s next goal of developing high-performance transistors that could operate on the surface of Venus. Such transistors could also be used on Earth in electronics for applications like extracting geothermal energy or monitoring the inside of jet engines.

“Transistors are the heart of most modern electronics, but we didn’t want to jump straight to making a gallium nitride transistor because so much could go wrong. We first wanted to make sure the material and contacts could survive, and figure out how much they change as you increase the temperature. We’ll design our transistor from these basic material building blocks,” says John Niroula, an electrical engineering and computer science (EECS) graduate student and lead author of the paper.

His co-authors include Qingyun Xie PhD ’24; Mengyang Yuan PhD ’22; EECS graduate students Patrick K. Darmawi-Iskandar and Pradyot Yadav; Gillian K. Micale, a graduate student in the Department of Materials Science and Engineering; senior author Tomás Palacios, the Clarence J. LeBel Professor of EECS, director of the Microsystems Technology Laboratories, and a member of the Research Laboratory of Electronics; as well as collaborators Nitul S. Rajput of the Technology Innovation Institute of the United Arab Emirates; Siddharth Rajan of Ohio State University; Yuji Zhao of Rice University; and Nadim Chowdhury of Bangladesh University of Engineering and Technology.

Resistance and Performance Under Heat

While gallium nitride has recently attracted much attention, the material is still decades behind silicon when it comes to scientists’ understanding of how its properties change under different conditions. One such property is resistance, the flow of electrical current through a material.

A device’s overall resistance is inversely proportional to its size. But devices like <span class="glossaryLink" aria-describedby="tt" data-cmtooltip="

Semiconductors are materials with electrical conductivity that falls between conductors and insulators, making them essential for modern electronics. They are typically crystalline solids, the most common of which is silicon, used extensively in the production of electronic components such as transistors and diodes. Semiconductors are unique because their conductivity can be altered and controlled through doping—adding impurities to the material to change its electrical properties. This property allows them to serve as the foundation for integrated circuits and microchips, powering everything from computers and smartphones to advanced medical devices and renewable energy technologies. The behavior of semiconductors is also crucial in the development of various electronic, photonic, and quantum devices.

” data-gt-translate-attributes=”[{"attribute":"data-cmtooltip", "format":"html"}]” tabindex=”0″ role=”link”>semiconductors have contacts that connect them to other electronics. Contact resistance, which is caused by these electrical connections, remains fixed no matter the size of the device. Too much contact resistance can lead to higher power dissipation and slower operating frequencies for electronic circuits.

“Especially when you go to smaller dimensions, a device’s performance often ends up being limited by contact resistance. People have a relatively good understanding of contact resistance at room temperature, but no one has really studied what happens when you go all the way up to 500 degrees,” Niroula says.

Testing Methodologies and Results

For their study, the researchers used facilities at MIT.nano to build gallium nitride devices known as transfer length method structures, which are composed of a series of resistors. These devices enable them to measure the resistance of both the material and the contacts.

They added ohmic contacts to these devices using the two most common methods. The first involves depositing metal onto gallium nitride and heating it to 825 degrees Celsius for about 30 seconds, a process called annealing.

The second method involves removing chunks of gallium nitride and using a high-temperature technology to regrow highly doped gallium nitride in its place, a process led by Rajan and his team at Ohio State. The highly doped material contains extra electrons that can contribute to current conduction.

“The regrowth method typically leads to lower contact resistance at room temperature, but we wanted to see if these methods still work well at high temperatures,” Niroula says.

Stability and Performance at High Temperatures

They tested devices in two ways. Their collaborators at Rice University, led by Zhao, conducted short-term tests by placing devices on a hot chuck that reached 500 degrees Celsius and taking immediate resistance measurements.

At MIT, they conducted longer-term experiments by placing devices into a specialized furnace the group previously developed. They left devices inside for up to 72 hours to measure how resistance changes as a function of temperature and time.

Long-Term Stability and Improvements

Microscopy experts at MIT.nano (Aubrey N. Penn) and the Technology Innovation Institute (Nitul S. Rajput) used state-of-the-art transmission electron microscopes to see how such high temperatures affect gallium nitride and the ohmic contacts at the atomic level.

“We went in thinking the contacts or the gallium nitride material itself would degrade significantly, but we found the opposite. Contacts made with both methods seemed to be remarkably stable,” says Niroula.

While it is difficult to measure resistance at such high temperatures, their results indicate that contact resistance seems to remain constant even at temperatures of 500 degrees, for around 48 hours. And just like at room temperature, the regrowth process led to better performance.

The material did start to degrade after being in the furnace for 48 hours, but the researchers are already working to boost long-term performance. One strategy involves adding protective insulators to keep the material from being directly exposed to the high-temperature environment.

Future Prospects in Microelectronics

Moving forward, the researchers plan to use what they learned in these experiments to develop high-temperature gallium nitride transistors.

“In our group, we focus on innovative, device-level research to advance the frontiers of microelectronics, while adopting a systematic approach across the hierarchy, from the material level to the circuit level. Here, we have gone all the way down to the material level to understand things in depth. In other words, we have translated device-level advancements to circuit-level impact for high-temperature electronics, through design, modeling and complex fabrication. We are also immensely fortunate to have forged close partnerships with our longtime collaborators in this journey,” Xie says.

Reference: “High temperature stability of regrown and alloyed Ohmic contacts to AlGaN/GaN heterostructure up to 500 °C” by John Niroula, Qingyun Xie, Nitul S. Rajput, Patrick K. Darmawi-Iskandar, Sheikh Ifatur Rahman, Shisong Luo, Rafid Hassan Palash, Bejoy Sikder, Mengyang Yuan, Pradyot Yadav, Gillian K. Micale, Nadim Chowdhury, Yuji Zhao, Siddharth Rajan and Tomás Palacios, 15 May 2024, Applied Physics Letters.
DOI: 10.1063/5.0191297

This work was funded, in part, by the U.S. Air Force Office of Scientific Research, Lockheed Martin Corporation, the Semiconductor Research Corporation through the U.S. Defense Advanced Research Projects Agency, the U.S. Department of Energy, Intel Corporation, and the Bangladesh University of Engineering and Technology.

Fabrication and microscopy were conducted at MIT.nano, the Semiconductor Epitaxy and Analysis Laboratory at Ohio State University, the Center for Advanced Materials Characterization at the <span class="glossaryLink" aria-describedby="tt" data-cmtooltip="

University of Oregon
The University of Oregon, located in Eugene, Oregon, is a prominent public research university known for its strong programs in a variety of fields, including journalism, architecture, and environmental studies. Founded in 1876, it is the state's third oldest university and offers a wide range of undergraduate and graduate programs. In terms of research, the University of Oregon has a robust emphasis on interdisciplinary studies, innovation, and sustainability. It houses several notable research centers and institutes, including the Phil and Penny Knight Campus for Accelerating Scientific Impact, which aims to fast-track scientific discoveries into innovations that improve the quality of life for people in Oregon, the nation, and beyond.

” data-gt-translate-attributes=”[{"attribute":"data-cmtooltip", "format":"html"}]” tabindex=”0″ role=”link”>University of Oregon, and the Technology Innovation Institute of the United Arab Emirates.