Wolfspeed Expands SiC Manufacturing Capabilities With Ion Implant System
Axcelis has announced shipment of a Purion H200 SiC ion implant system to Wolfspeed to support expanded production of power semiconductor products for EV and other high-voltage applications.
Axcelis Technologies will be shipping the Purion H200 ion implant system to Wolfspeed to support the expansion of Wolfspeed’s silicon carbide (SiC) fab infrastructure and manufacturing capabilities.
Purion H series ion implant system. Image used courtesy of Axcelis
The investment is driven by the continued rapid growth of the EV market and demand for the high-voltage components necessary for their design and operation.
According to Wolfspeed, the popularity of electric vehicles is only steepening, and the company is focused on scaling production capacity to meet demand for its SiC products.
The Purion H200 system will be used for high-current ion implant applications in Wolfspeed’s silicon carbide production process.
What Is an Ion Implant System?
Ion implantation is a form of doping essential to semiconductor and integrated circuit manufacturing.
Doping, or modifying, a semiconductor wafer is the process by which “impurities” are introduced into the wafer material to alter its electrical properties to form semiconductor devices like MOSFETs, Diodes, discrete transistors, and integrated circuits.
Common semiconductor materials for substrates and doping. Image used courtesy of Toshiba
Ion implanters generate a steerable ion beam, formed from the desired source material, that implants the ions at the required depth and uniformity beneath the surface of the substrate. The amount of energy applied in the implant process determines the speed and depth at which the impurities are embedded.
Due to the high currents required, doping with aluminum (Al) is a significant challenge during the SiC wafer manufacturing process. Axcelis’ proprietary aluminum implant technology delivers the current levels needed to properly implant Al while maintaining sufficient beam stability to meet manufacturing productivity requirements.
The Purion H200 is the newest Axcelis H series of high-current ion implanters and is designed to meet the needs of the high-power device manufacturing market.
The new platform offers innovations in source handling (i.e., aluminum for p-type SiC) and the high-temperature wafer handling needed to properly implant ions. For SiC, wafers can reach temperatures as high as 700 °C during the implant process, and this temperature must be precisely controlled to include thermal uniformity across the wafer.
Ion beam implants doping impurities into a SIC wafer. Image used courtesy of Axcelis
Fully Integrated SiC Manufacturer
Wolfspeed is a fully integrated SiC manufacturer starting with the capability of manufacturing SiC wafers from raw silicon and carbide materials.
The company uses a proprietary crystal growth process based on a seeded-sublimation process that requires precise control and methodical development to yield high-quality substrates with fewer and smaller defects.
SiC wafer development process. Image used courtesy of Wolfspeed
The finished SiC wafers are then sent through an epitaxial process where nitrogen, aluminum, or other impurities are doped into the substrate to create n-type or p-type properties.
Wolfspeed portfolio of high-voltage substrate wafers. Image used courtesy of Wolfspeed
From the finished wafers, high-voltage devices can be fabricated and diced into individual die that can be packaged, sold in die form, or integrated into power modules for use in EV powertrain, charging, and other high-voltage applications.
