First GaN-on-Silicon Devices on 200-mm Wafers
X-FAB Silicon Foundries and Exagan, a start-up innovator of gallium-nitride (GaN) semiconductor technology enabling smaller and more efficient electrical converters, have demonstrated mass-production capability to manufacture highly efficient high-voltage power devices on 200-mm GaN-on-silicon wafers using X-FAB’s standard CMOS production facility in Dresden, Germany.
This accomplishment is the result of a joint development agreement launched in 2015, enabling cost/performance advantages that could not be achieved with smaller wafers. Exagan and X-FAB have successfully resolved many of the challenges related to material stress, defectivity and process integration while using standard fabrication equipment and process recipes. Combined with the use of 200-mm wafers, this will significantly lower the cost of mass producing GaN-on-silicon devices. By enabling greater power integration than silicon ICs, GaN devices can improve the efficiency and reduce the cost of electrical converters, which will accelerate their adoption in applications including electrical vehicle charging stations, servers, automobiles and industrial systems.
The new GaN-on-silicon devices have been built using substrates fabricated at Exagan’s 200-mm epi-manufacturing facility in Grenoble, France. These epi wafers meet the physical and electrical specifications to produce Exagan’s 650-volt G-FET devices as well as the tight requirements for compatibility with CMOS manufacturing lines. The industry’s previous work with GaN had been limited to 100-mm and 150-mm wafers due to the challenges of layering GaN films on silicon substrates. Exagan’s G-Stack technology enables GaN-on-silicon devices to be manufactured more cost effectively on 200-mm substrates by depositing a unique stack of GaN and strain-management layers that relieves the stress between GaN and silicon layers.
The resulting devices have been shown to exhibit high breakdown voltage, low vertical leakage and high-temperature operation. “This is a major milestone in our company’s development as we accelerate product development and qualification,” said Frédéric Dupont, president and CEO of Exagan. “It demonstrates the combined strengths of our epi material, X-FAB’s wafer fab process and our device design capabilities. It also confirms the success of our vertically integrated fab-lite model, with expertise from materials to devices and applications. It’s perfect timing to establish GaN technology and products on the most competitive 200-mm platform just as GaN power products are getting broad traction in IT server, consumer electronics and automotive markets.” “We have high confidence in Exagan’s leadership team and product performance roadmap,” said Rudi De Winter, CEO of X-FAB. “Through this productive partnership, X-FAB is leveraging its resources and expertise to bring Exagan’s technology into manufacturing and provide the power conversion market with a reliable supply chain.” Exagan will showcase this GaN technology and G-FET transistors at the PCIM Europe trade show, May 16-18 in Nuremberg, Germany.