Objective 1: Innovation on advanced carrier wafer technologies for GaN devices (WP 1)
Fabrication of demonstrators on the different substrates and evaluate the merits of the concepts on device level and benchmarking with respect to the reference process has been fully met.
Several carriers were identified which offer benefits for GaN growth. Moreover, no current report in the literature has shown results on advanced carrier wafer technologies and we can thus claim that the results achieved in PowerBase are beyond state of the art.
Objective 2: Expand the limits in ON resistance of low ohmic power transistors (WP 2)
Improvement of stability and yield for the new 300mm very low resistance crystal growth process, enabling the process freeze for the final device qualification at Infineon. Substrate resistivity down to 1 mOhmcm were reached, and compared to 200mm a better thermal conductivity is realized. The 300mm-based low ohmic PowerMos transistor has shown superior matching with the 200mm state-of-the art device for voltage classes from 40V – 100V (reliability tests passed) - technology ready for commercialisation.
Objective 3: Provide reliability test methodologies and analysis tools for novel GaN power switches on advanced carrier substrates in new 3D integration (WP 6)
Succesful development of methodologies suitable for reliability evaluation in an industrial environment (evaluation of production-level GaN HEMT devices, identification of failure modes and mechanisms of PowerBase devices, development of reliability models)
• Methodology to assess yield loss minimizing test limits for high temperature operating life test (this was not available before PowerBase).
• Identification of leakage conduction mechanisms in conventional and engineered substrates
• Identification & Understanding of most dangerous failure modes and mechanisms of power GaN HEMTs: vertical drain-to-substrate time-dependent breakdown (TDDB), gate-stack time dependent breakdown, hot-electron degradation
Objective 4: Enable MtM solution for high variability (WP 4+5)
GaN packaging and assembly: Evaluation of different high thermal conductive mold compounds. Investigation of different levels of vacuum during molding process for process ability and void reduction. Development of pressure assisted Ag sintering including routine quality analysis methodology.
Heterogeneous 3D integration: Optimization/Integration of multiple single process steps of TSV- and optical filter technology in the 3D processing pilot line (Improved plasma etch and -cleaning processes, Pilot line production readiness of a TSV capping process)
Exploration of limits of wafer-level-molding technology to create sub-milimeter lens structures led to the production of demonstrator samples.
Objective 5: Setup a pilot line for normally-on and normally-off GaN power devices (WP3)
Full establishment of the pilot lines with corresponding processes, control concepts and electrical parameter tests for the manufacturing of pGaN normally-off power HEMTs in 150mm and normally-on Schottky RF power HEMTs in 200mm.
Process of fully integrated normally-off wafer lots in the industrial pilot line. Tested and packaged parts shipped to PowerBase partners for reliability testing and assembly in application demonstrators.
Evaluation of advanced substrates GaN-on-Si high-voltage (epitaxy grown on p+ Si substrates, corresponding wafers processed with full normally-off process in industrial pilot line).
Objective 6: Enhance the compliance of GaN in standard packages and modules (WP 5+4)
GaN process “pre-die” developed in the pilot line - installed in Regensburg (half-bridge device application demonstrator 2018)
Universal handler equipment concept was finished for future extension of the pilot line after PowerBase.
More than Moore 3D integration was demonstrated with the heterogeneous integration pilot line. The integration was shown on an active interposer design based on an existing optical sensor device.
Objective 7 & 8: Achieve benchmark size and significant improvement in energy management (WP 7)
Demonstrators developed, operating, performance tested - benefits and improvements evaluated for solar inverter, battery charger and power supplies for automation systems.
LED-lighting demonstrator based on PowerBase
Telcommunication application - high efficiency rectifier on the market, showing benchmark results in size and power efficiency under real field conditions
