650V SiC MOSFET Dies for Sintering

At Wolfspeed a new 650V SiC MOSFET chip is designed, fabricated, and tested for use in dual-side soldering and sintering processes. The on-resistance was measured to be ~7mΩ up to 150A at 25°C in package form. The corresponding specific on-resistance is 1.8mΩ·cm². The SiC MOSFET chip had a mean measured breakdown of 964V, with 31V standard deviation, across a population of 400 die. Only a 35-40% increase in on-resistance was measured from 25°C to 150°C. With no knee voltage, conduction losses relative to comparably rated Si IGBT power modules can be reduced up to 80%. The top-side Ni:Au plated metal stack designed for top-side soldering or sintering eliminates top-side wirebonds, which are often a point of failure in power cycling and will also allow for dual side cooling of the device in the package. Due to SiC’s relatively small die size compared with Si, the thermal excursions could be wider, amplifying the advantage of wirebond-free modules. The device will be introduced at PCIM Europe. AS

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