A High Temperature, High Power Density Package for SiC and GaN Power Devices

Abstract

In this work, a compact 600 – 1700 V high current power package housing either silicon carbide (SiC) or gallium nitride (GaN) power die was designed and developed. Several notable configurations of the package include diode half-bridges, co-packed MOSFET-diode pairs, and cascode configured GaN devices. In order to avoid a significant redesign effort for each new application or improvement in device technology, a device-neutral design strategy enables the use of a variety of die types from any manufacturer depending on the end-use application's requirements. The basic SOT-227 is a widely used package type found in everything from electronic welders and power supplies to motor controls and inverters. This module is a variant of that style of package which also addresses some issues that a standard SOT-227 package has when used in higher voltage applications; it has increased creepage and clearance distances which meet IPC, UL, and IEC standards up to 1700 volts while retaining an isolated substrate. It also has low parasitic values in comparison to the SOT-227. One of the key elements of this design is the removal of the baseplate. This allows for far lower weight, volume, and cost as well as reduced manufacturing complexity. The wide bandgap power package is composed of high temperature capable materials, which allow for the high junction temperatures inherent in these high power density devices. This paves the way for the design of a small, low-profile package with low parasitic inductances and a small junction-to-case thermal resistance. This paper will discuss the mechanical design of the power package as well as the three-dimensional finite-element modeling and analysis of the thermal, electrical, and mechanical characteristics. In addition, the electrical characteristics as a function of temperature of the power module up to 225 °C will be presented.