The Figure of Merit of a Semiconductor Power Electronics Switch

The figure of merit (FOM) of a semiconductor device represents an important quality as it pertains to its performance limits and is often used to drive the technology development in a specific direction. Comparing the performances of switching power MOSFETs using their FOMs has become ubiquitous practice in power semiconductor and power electronics industries. In this paper, a critical review of the proposed power MOSFET FOMs is presented, and key limitations are discussed. It is shown that the quality factor Q
_F2
= (λE
_c
/R
_ON,sp
) along with Q
_G
and Tjmax may be used to guide the development of future generations of power semiconductor device technologies for power electronics switching applications, where λ and Ec are the thermal conductivity and critical electric field strength for the avalanche breakdown of the semiconductor material, respectively, RON,sp is the specific on-state electrical resistance, Q
_G
is the gate charge, and T
_jmax
is the maximum junction temperature of the semiconductor power device, respectively.