WP1 "Vertical Power GaN" investigated technologies for vertical GaN device manufacturing, a technology suited for high voltage applications. The focus was on the carrier substrate choice for reduced device production cost. Two technologies for manufacturable vertical devices on large scale diameter were investigated – Si substrates and QST® (engineered substrate with a poly-AIN core). For Si substrates we successfully could model the possibility of 10-12 µm thick drift layers on 200-mm-diameter. For GaN on QST® 12 µm could be already demonstrated and a full device-manufacturing circle with 8 µm+ stacks on 200 mm-diameter substrates was performed without wafer breakage. Both technologies still need further investigation.
WP2 "Benchmark Lateral Power GaN" aimed for or the next levels of performance and cost improvement for lateral GaN power technologies. Ultra-compact and best-in-class 100V and 600V normally-off GaN power HEMTs have been realized on 200mm Silicon substrates resulting in a substantial productivity increase compared to state-of-the-art 150mm technologies. We successfully developed the underlying 200mm GaN-on-Si epitaxial processes, including design optimization of reactor hardware and reached optimum 100V and 600V device designs for advanced interconnect and packaging schemes, allowed improved epitaxy as well as device processes, and ensured the matching of requirements and device performance for the different use cases.
WP3 "GaN on Silicon RF Break Through" went for a „GaN on Silicon RF Break Through” an area where after 20 years of research still a lack of performance limits the possible success. Based on an existing RF-GaN on Si technology as the baseline, a novel transistor concept was implemented to push the gain-performance (enabling higher efficiencies) beyond state-of-the art. The research focused on improving substrates, epi and transistor processing. The feasibility of a GaN on Si RF-transistor with characteristics close to GaN on SiC could be shown.
WP4 "Assembly and Packaging of high speed and high frequency GaN on Si devices" focused on harvesting the advantageous properties (increased power densities and high switching frequencies for low loss energy conversion) of GaN FETs, by achieving lowest parasitic impedance in the electronic package. For the applications in the use-cases, WP4 was able to provide plateable mold packages for lowest Rdson through customized laser treatment of the mold body´s surface. Furthermore, PCB embedded GaN realized with Central Core Embedding (CCE) allowed the production of miniaturized RF power amplifiers modules, outperforming surface mounted MCM SiPs. A System in Package for shortpulse LiDAR in ADAS, taking into account the special needs of the laser diodes, was developed using flip chip configurations.
WP5 "GaN Reliability and Defect Research" aligned forces on GaN reliability and defect research to analyze performance- and reliability mechanisms in advanced GaN devices along the full value chain from the development of new methodologies for reliability, to material-level analysis, from device-level investigation, to system-level evaluation. Research results are ready to be exploited by the partners, in the fields of advanced methodologies for reliability, of defect/reliability interpretation, and of reliability-oriented system design.
WP6 "GaN RF and Power Applications" was dedicated to reach benchmark achievements of GaN devices developed and to demonstrate different RF and power applications in 6 use-cases:
UC1: Rectifiers with GaN technology for telecom & data centers – demonstrator achieved 97.8 % efficiency
UC2: GaN power amplifiers for RF frontends for 5G and radar – 5G RF amplifier (Doherty) demonstrator measured with GaN-Si devices. Top-level efficiency of 45% was achieved with higher bandwidth.
UC3: Nano-Second-Pulsed-Laser Driver for LiDAR – demonstrated 40 A in less than 5 ns following a low parasitic inductance approach.
UC4: Battery Charger for PHEV/EV – achieved reliable demonstrators for contact on-board charger (high-efficient, high-power-density) and for a wireless battery charger with a peak efficiency of 96% (best available industrial systems between 90% and 93%).
UC5: Single-phase PV Inverter – resulted in a fully GaN 10kW single-phase photovoltaic inverter demonstrator based on new GaN modules (increased power-density, reduced cost of the system)
UC6: Isolated GaN power converters for native DC microgrids – demonstration of an integrated DC microgrid to interconnect different renewable energy sources (loads and energy storage systems).
