Work

GaN half-bridges on electrical and thermal co-designed ceramic substrates

Year: 2025

Type: article

Abstract: This work presents an analysis of an electrically and thermally optimized GaN half-bridge module based on ceramic a substrate. An effective thermal and electrical co-design is a decisive factor in achieving high efficiency and power density. In order to utilize the advantages of both GaN for high switching frequencies and ceramic substrates for excellent thermal properties , an electrical and thermal co-designed substrate stack-up for MHz applications is presented. This stack-up features a 40 μ m thin ceramic layer resulting in a measured power loop inductance of L loop,VNA = 489 p H and a ceramic carrier for an electrically isolated and thermally optimized connection to the heat sink. In a 48 V to 24 V buck converter switching at frequencies of up to 2 MHz, a difference in efficiency of 1% is achieved compared to a electrically enhanced rigid-flex substrate using a 25 μ m polyimide layer. At a switching frequency of 500 kHz, a power density of 1 kW/cm 3 is achieved with an efficiency of over 95%, accompanied by the possibility of significantly improving the thermal resistance with an all-ceramic stack-up, which enables GaN half-bridges with high frequencies and power densities.

Source: Power Electronic Devices and Components

DOI: 10.1016/j.pedc.2025.100091