Lin Cai, a distinguished professor in the Department of Electrical and Computer Engineering, has been recognized for her groundbreaking work in the realm of sustainable wireless communication and networking. Her research endeavors are focused on the intricate design and optimization of energy-efficient wireless systems, driving innovations in resilient wireless networks that are crucial for the burgeoning Internet of Things (IoT). As wireless technology becomes increasingly vital in our everyday lives, Cai’s work addresses the environmental impact of large-scale communication networks. By integrating machine learning techniques with network optimization, her research paves the way for more eco-friendly solutions in wireless communications.

Cai’s impact extends beyond academia; she is a recipient of the National Science Foundation CAREER Award, which is highly regarded in the engineering community. Through this award, Cai has advanced the design and deployment of communication networks that are powered by renewable energy sources such as solar and wind. This enables a sustainable approach to managing the growing energy demands of modern communication systems, while also enhancing their resilience in the face of environmental challenges. Her dedication to this field is helping shape the next generation of sustainable communication systems, ensuring they are both efficient and environmentally responsible.

Boris S. Pervan, a professor and Frank Gunsaulus Faculty Fellow in Mechanical and Aerospace Engineering, has been acknowledged for his contributions to satellite navigation integrity. His research focuses on enhancing the accuracy and integrity of navigation systems, a critical aspect for any GPS-driven application. High integrity in satellite navigation systems is paramount, particularly for safety-critical operations such as aviation and autonomous vehicles, where any slight deviation can have serious consequences. Through his work, Pervan is pioneering advancements that ensure not only precise navigation but also the reliability necessary to maintain safety standards.

In his role as the director of the Center for Assured and Resilient Navigation in Advanced Transportation Systems (CARNATIONS) at Illinois Tech, Pervan leads collaborative efforts between the university and industry to develop safe, scalable, and seamless navigation systems for uncrewed aircraft. This ambitious $10 million project, funded by the United States Department of Transportation, aims to create robust navigation solutions that can withstand the complexities of airspace interactions and ensure safe operations across various transportation modes.

With his extensive background in the field, Pervan has distinguished himself as a fellow of the Institute of Navigation (ION) and an associate fellow of the American Institute of Aeronautics and Astronautics. His recent accolade, the prestigious Johannes Kepler Award from ION, highlights his unwavering commitment to the advancement of high-integrity Global Navigation Satellite System (GNSS) technology. This recognition is a testament to Pervan’s dedication to the field, emphasizing his contributions to both navigation technology and education.

Thomas Wong, professor emeritus of electrical and computer engineering, has also garnered recognition for his vital contributions to high-frequency electronics and materials characterization. Wong’s long-standing academic career, which began in 1981, has been marked by significant research advancements in material measurements and charge transport within various conductors, ranging from ionic to electronic. His research has had far-reaching implications in millimeter-wave communication systems and the propagation effects observed in high-speed semiconductor devices and integrated circuits.

Wong’s work in collaboration with prestigious research institutions such as Argonne National Laboratory and Fermilab underscores the importance of interdisciplinary approaches in tackling complex engineering challenges. His research initiatives have explored dielectric-loaded accelerators and the design of couplers for superconducting multicell cavity resonators, contributing to a foundational understanding of these intricate systems. Furthermore, Wong’s innovative investigations into nanoscale position sensors highlight the intersection of advanced materials and electronic applications, demonstrating a forward-thinking approach to engineering design.

Wong’s scholarly contributions extend to authorship, with his seminal work on distributed amplifiers published in 1993 being the first book dedicated to the subject. His expertise has earned him recognition as a fellow of the International Association of Advanced Materials, reflecting his stature in the scientific community. Through this recognition, Wong continues to influence the field by sharing knowledge and mentoring the next generation of engineers.

The recognition of these three faculty members as IEEE fellows is not just an honor; it reflects the remarkable research environment at Illinois Tech, where innovative ideas converge to address pressing challenges in engineering and technology. The work of Cai, Pervan, and Wong exemplifies the university’s commitment to fostering talent and inspiring future advancements in electrical and computer engineering, aerospace systems, and high-frequency electronics.

This achievement stands as a milestone not only for the individuals involved but also for the broader academic community, as it emphasizes the critical role that universities play in driving technological progress. By nurturing researchers who are dedicated to addressing the complexities of modern communication and navigation systems, Illinois Tech is paving the path toward a more sustainable and safe technological future.

In conclusion, the elevation of Lin Cai, Boris S. Pervan, and Thomas Wong to the rank of IEEE fellows serves as an inspiring reminder of the vital contributions made by academic institutions to the field of engineering. Their research not only enhances our understanding of theoretical concepts but also provides actionable solutions that can be implemented in real-world scenarios. As the landscape of technology continues to evolve, the insights offered by these esteemed professors will undoubtedly shape the next generation of innovations that benefit society as a whole.

Subject of Research: Contributions to wireless communication, satellite navigation integrity, and high-frequency electronics
Article Title: Illinois Institute of Technology Faculty Members Recognized as IEEE Fellows
News Publication Date: Not specified
Web References: Not available
References: Not available
Image Credits: Credit: Illinois Institute of Technology

Keywords

Applied sciences, Engineering, Electrical engineering, Telecommunications, Navigation, Electronics

Recent scientific endeavors have turned the spotlight on scandium aluminum nitride (ScAlN) as a promising barrier material capable of augmenting the already impressive performance metrics of GaN-based HEMTs. ScAlN distinguishes itself through substantial spontaneous and piezoelectric polarization effects, which can drive the electron density within the 2DEG to unprecedented levels. Moreover, ScAlN’s intrinsic ferroelectricity opens up fascinating avenues for dynamically tunable ferroelectric gates, potentially revolutionizing device functionalities by enabling electrical modulation of the 2DEG channel in ways previously unattainable in conventional GaN HEMT architectures.

Traditional techniques for synthesizing ScAlN layers atop GaN substrates entail complex epitaxial methods, often requiring elevated temperatures and expensive equipment, thereby restricting scalability and industrial adoption. Contrastingly, the physical vapor deposition technique known as sputtering emerges as an attractive alternative due to its relative simplicity, rapid deposition rates, and compatibility with lower processing temperatures. Despite its industrial promise, the investigation into sputtering-grown ScAlN films and the influence of deposition parameters on their structural and electrical traits has remained scarce, presenting a crucial knowledge gap for semiconductor researchers and manufacturers alike.

Addressing this gap, a pioneering team of researchers led by Associate Professor Atsushi Kobayashi at Tokyo University of Science (TUS), Japan, has accomplished successful growth of ScAlN films on AlGaN/GaN heterostructures through sputter epitaxy. Their study meticulously explores the pivotal role of substrate temperature during deposition, unveiling how thermal conditions underpin the crystalline quality and the electrical performance of these thin films. This research underscores sputtering’s viability as a cost-effective, scalable method to integrate ScAlN barriers in high-performance GaN HEMTs, thereby propelling these devices closer to widespread commercial utilization.

In their experimental approach, the researchers fabricated ScAlN films with approximately 10% scandium doping on AlGaN/AlN/GaN substrates, systematically varying growth temperatures between 250 °C and 750 °C. Utilizing advanced characterization techniques, including atomic force microscopy and high-energy electron diffraction, the team discerned that epitaxial alignment of ScAlN with the underlying heterostructure was achievable even at the relatively modest temperature of 250 °C. Furthermore, increasing thermal budgets notably enhanced surface morphology, culminating in atomically stepped terraces indicative of superior crystallinity at 750 °C deposition.

Crucially, the investigation into electrical properties via Hall-effect measurements revealed a pronounced dependency on growth temperature. The sample grown at 750 °C exhibited a sheet carrier density in the 2DEG exceeding 1.1 × 10¹³ cm⁻², nearly tripling that observed in comparable heterostructures lacking the ScAlN barrier. This stark enhancement evidences the integral role that improved structural order, fostered by optimized thermal conditions, plays in modulating interfacial electronic characteristics. Lower-temperature-grown films, conversely, demonstrated diminished carrier densities, highlighting the trade-offs associated with insufficient thermal energy to promote lattice perfection.

Despite the boost in carrier concentration, electron mobility experienced a decrement in all ScAlN-containing samples relative to baseline AlGaN/AlN/GaN heterojunctions. This mobility reduction is postulated to stem from increased structural roughness and defect states proximate to the interfaces introduced by the ScAlN layer, underscoring the delicate balance between carrier density augmentation and maintenance of high carrier mobility. These findings illuminate the nuanced interplay between microstructural quality and electronic transport mechanisms, serving as a powerful guide for future optimization of growth protocols.

The implications of this research are manifold. By demonstrating that sputter epitaxy can reliably produce high-quality ScAlN films under industrially relevant conditions, the study paves the way for scalable manufacturing of GaN-based HEMTs with enhanced 2DEG densities. Such advances bear direct relevance to the burgeoning fields of energy-efficient power electronics and ultra-fast wireless communications, where device performance is often constrained by material imperfections and fabrication expenses.

Associate Professor Kobayashi emphasizes the transformative potential of this work, noting that its success could catalyze mass production of next-generation transistor technologies capable of functioning robustly in extreme environments. This encompasses electric vehicles and aerospace applications, domains where high efficiency, reliability, and sustainability are paramount. In this regard, sputtered ScAlN barriers stand to not only advance electronic device capabilities but also contribute materially towards the global push for greener, more resilient technologies.

Looking ahead, the researchers anticipate that their findings will stimulate broader exploration into the integration of ferroelectric ScAlN layers within GaN-based devices. Such devices may harness voltage-controlled modulation of the 2DEG channel, unlocking functionalities such as non-volatile memory, adaptive RF components, or novel logic architectures. The facile and cost-effective nature of sputtering as a deposition technique further amplifies the appeal of this material system, potentially enabling versatile semiconductor platforms well beyond current limitations.

In sum, this study expands the theoretical understanding and practical methodology associated with ScAlN deposition on GaN heterostructures, marking a pivotal step in realizing advanced electronic materials. By meticulously correlating growth temperature with film structure and electronic properties, the work supplies invaluable insight to material scientists and device engineers alike, guiding the refinement of fabrication techniques that harmonize performance, cost, and scalability.

As the electronics industry relentlessly pushes to transcend classical material boundaries, innovations like sputtered ScAlN barriers promise to redefine the limits of high-frequency transistor technology. With this breakthrough, the door opens wider to the widespread adoption of high-performance, scalable GaN devices, poised to accelerate technological frontiers spanning communication, energy systems, and beyond.

Subject of Research: Not applicable

Article Title: Effect of growth temperature on the structural and electrical properties of sputter-epitaxial ScAlN on AlGaN/AlN/GaN heterostructures

News Publication Date: 7-Aug-2025

References: DOI: 10.1063/5.0281540

Image Credits: Dr. Atsushi Kobayashi from Tokyo University of Science, Japan

Keywords

Materials science, Electronics, Electrical engineering, Applied sciences and engineering, Energy