SweGaN Technology Introduces ‘Buffer-Free’ Concept For GaN High-Frequency DevicesJune 12, 2020 by Antonio Anzaldua Jr.
In a recent collaboration with the Chalmers University of Technology, SweGaN introduced a 'buffer-free' concept for GaN-on-SiC electron mobility transistors that brings promising commercial benefits for GaN devices, telecommunication, and space applications.
SweGaN is a Swedish manufacturer of custom-made GaN-on-SiC epitaxial wafers for radio frequency (RF) and power components and devices. In a recent study, SweGaN teamed up with Chalmers University of Technology Department of Microtechnology and Nanoscience (MC2) to perform a new benchmark for GaN high-frequency devices. MC2 is a unique research department that primarily focuses on future nano and quantum electronics. They work closely with their Swedish partners in providing positive and environmentally impactful GaN devices.
Cross-sectional TEM image at the interface of the GaN/AIN/SiC region. Image used courtesy of SweGaN.
In a joint study, SweGaN and MC2 utilized SweGaN’s QuanFINE epitaxial wafer to compare with conventional buffer epi-structures. QuanFINE is a hybrid structure that combines high-electron-velocity thin gallium nitride (GaN) with high-breakdown bulk silicon carbide (SiC).
QuanFINE Structure is “buffer-free can outperform conventional materials at the device level without compromising device performance. Image used courtesy of SweGaN.
QuanFINE’s growth process allows channel electrons to exhibit state-of-the-art mobility of >2000 cm2/V-s, in the heterostructures without a conventional buffer layer. This is approximately 30% higher than typical channel electron mobility. Defect formation in the initial epitaxial growth phase is alleviated which creates an added GaN channel layer, ideal for high-electron-mobility transistors (HEMTs). The highly scaled transistor processed on the heterostructure with a nearly perfect GaN–SiC interface enables high efficiency for DC and microwave performances.
After evaluations, SweGaN and MC2 claimed QuanFINE epi-wafers improved electron confinement, demonstrated lower buffer-induced dispersion, and provided high output power and efficiency levels in comparison to conventionally doped buffers. The SweGaN’s Chief Technology Officer, Dr. Jr-Tai Chen stated, “Currently, GaN-on-SiC epitaxial wafers for Ka-band applications are either immature or suffer from severe trade-offs. Our QuanFINE epi-wafers are a highly feasible solution that can resolve issues our customers are dealing with regarding short-channel effects in the high-frequency devices.”
GaN Devices, Telecommunication, and Space Applications
Power and high-frequency devices face performance and efficiency issues. For certain applications, such as space missions, satellite components have to robust and energy-efficient to withstand extreme conditions. SweGaN’s materials enable devices to have longer battery life and low power consumption due to a thermal manager.
The ultra-low Thermal Boundary Resistance (TBR) in the GaN-SiC interface provides RF and power devices with reliability and an increased device lifespan. Image used courtesy of SweGaN.
There is up to 40% additional channel temperature rise in transistors. By utilizing SweGaN’s ultra-low thermal boundary resistance layer, the device is able to reduce any additional temperature rise to a negligible level. This improves heat transport from the channel down to the SiC substrate, reducing the operating temperature by 25 degrees celsius.
For high-frequency applications, QuanFINE features a buffer-free HEMT heterostructure, where the AlN nucleation layer serves effectively as a back-side barrier. Therefore, the electrons in the thin GaN channel (< 250 nm) are well confined in the quantum-well–like structure by the front-side and back-side barriers.
QuanFINE also offers efficient thermal management that bings promising advances in a wide spectrum of high-frequency and power electronics.
A “Buffer-Free” Concept For 5G and Beyond
For SweGaN customers and manufacturers, the ultimate benefits resulting from the new ‘buffer-free’ concept include lower trapping, better carrier confinement, and lower thermal resistance. These benefits suggest GaN high-frequency devices, utilizing the ‘buffer-free' concept may offer an alternative route for high-frequency GaN HEMTs with less electron trapping effects.
The world is entering 5G communication technologies that demand higher data rates, mobility, and network energy efficiency. From RF devices to high-resolution video streaming, the power dissipated and energy-efficiency from traditional power components need to be redesigned for the new networks. SweGaN along with various partners including MC2 are strategizing to continue to develop key elements for integrated circuits in order to stay ahead of the advancing 5G network.