Replacing Silicon Power MOSFETs

Summary

The silicon power metal oxide silicon field effect transistor (MOSFET) journey taught that there are some key variables controlling the adoption rate of a disruptive power management technology. As gallium nitride (GaN) transistors gain wider acceptance, becoming the successor of the power MOSFET, designers have been able to leverage the increased switching performance to improve power conversion system efficiency, size, and cost. Since the GaN transistor is a prime candidate to displace the mature, but aged, power MOSFETs, they provide the most meaningful cost comparison. The basic elements of product cost are: starting material; epitaxial growth; wafer fabrication; and test and assembly. If one considers that the GaN transistor requires less device area than a silicon device with similar current‐carrying capability, then the cost per function is lower for GaN transistors than for comparable Si MOSFETs. The cumulative reliability information available on silicon power MOSFETs is staggering.