Chip Size Minimization for Wide and Ultrawide Bandgap Power Devices

Abstract

Chip size (Achip) optimization is key to the accurate analysis of device and material costs and the design of multichip modules. It is particularly critical for wide bandgap (WBG) and ultrawide bandgap (UWBG) power devices due to high material cost. Moreover, the designs of Achip and the drift region thickness (Wdr) and doping concentration (Ndr) are interdependent, requiring their co-optimization. Current design practices for Achip, Wdr, and Ndr rely on optimizing electrical parameters. This work presents a new, holistic, electrothermal approach to optimize Achip for a given set of target specifications, including breakdownvoltage (BV), conductioncurrent (I0), and switching frequency (f ). The conduction and switching losses of the device are considered as well as the heat dissipation in the chip and its package. For a given BV and Io, the optimal Achip, Wdr, and Ndr show a strong dependence on f and thermal management. Such dependencies are missing in prior Achip design methods. This approach is applied to compare the optimal Achip of WBG and UWBG devices up to a BV over 10 kV and f of 1 MHz. Our approach offers more accurate cost analysis and design guidelines for power modules.