Power Diamond Systems has developed a monolithic bidirectional diamond switch by leveraging its proprietary diamond MOSFET technology. Using this device, the company has demonstrated bidirectional switching operation for the first time in the world, while achieving a bidirectional breakdown voltage of 290 V and an on-resistance of 8.2 mΩ·cm². Compared with previously proposed structures based on bulk conduction, the new device achieves a more than tenfold reduction in on-resistance while improving breakdown voltage. This achievement represents a significant step toward the practical realisation of bidirectional switches using diamond semiconductors.
In recent years, there has been a growing demand for the miniaturisation and cost reduction of power conversion systems, such as inverters for renewable energy and on-board chargers for electric vehicles. These systems require bidirectional voltage blocking, which has traditionally been realised by configuring bidirectional switches using back-to-back connected power devices. However, this approach increases the number of devices, resulting in constraints in terms of footprint and cost. In contrast, monolithic bidirectional switches that enable bidirectional operation on a single chip have the potential to reduce the footprint by more than half compared with back-to-back configurations. As a result, they are attracting significant attention worldwide as a promising technology for the high integration of next-generation power conversion circuits.
Monolithic bidirectional switches based on diamond semiconductor materials have also been proposed. However, conventional structures utilising bulk conduction suffer from high on- resistance due to the deep dopant levels inherent to diamond. In addition, large gate leakage currents have prevented stable operation as a bidirectional switch from being sufficiently demonstrated. Building on its proprietary diamond MOSFET technology, Power Diamond Systems has developed a diamond MOSFET structure optimised for bidirectional operation, in which two gates must be controlled simultaneously.
Using the newly developed monolithic bidirectional diamond switch, the company has demonstrated, for the first time in the world, the operating modes unique to bidirectional switching devices. In addition, the device achieved a bidirectional breakdown voltage of 290 V and a low on-resistance of 8.2 mΩ·cm². Furthermore, compared with conventional structures based on bulk conduction, the device successfully achieved a more than tenfold reduction in on-resistance while improving breakdown voltage. These results significantly advance both the performance and the practical feasibility of bidirectional switches using diamond semiconductors.
Looking ahead, Power Diamond Systems will continue to pursue higher breakdown voltage and lower on-resistance, while strengthening reliability evaluation. Through collaboration with external partners, the company will also accelerate application development, targeting use in renewable energy systems and electric vehicle power conversion systems, and contributing to the realisation of next-generation power electronics.
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