Thermal shock reliability of a GaN die-attach module on DBA substrate with Ti/Ag metallization by using micron/submicron Ag sinter paste

Abstract

This study was carried out to evaluate the reliability of GaN die-attached on a direct bonded aluminum (DBA) substrate with Ag sinter joining in up to 1000 harsh thermal shock cycles over a temperature range from −50 °C to 250 °C. For joining the die-attached structure, metallized Ti/Ag was prepared first on the substrates of DBA and GaN chips. A GaN die and DBA substrate were bonded by a micron/submicron Ag sinter paste in air at 250 °C without pressure. The initial die shear strength of the GaN/DBA joint structure, above 33 MPa, was retained up to 250 cycles and then gradually decreased up to 1000 cycles. Microstructural observation by field-emission scanning electron microscopy and energy-dispersive X-ray spectroscopy showed a crack growing inside the Ag/Al bonding interface during thermal cycles due to the large plastic deformation of the Al layer. In addition, with the aid of simulations based on the finite element method, the damage mechanism is discussed in further detail, including the Al grain boundary effect. This study systematically revealed that the mechanism of thermal shock damage of a GaN/DBA module with an Ag sinter joining structure suggests that it can prevent severe damage during thermal shocks in high-temperature applications.

Reconstruction of Pressureless Sintered Micron Silver Joints and Simulation Analysis of Elasticity Degradation in Deep Space Environment

“…The hydraulic diameter of the medium declines with fluctuation. If the porous medium is regarded as an interconnected pipeline network, the above situation can be interpreted as the rise of pore density and pore nucleation growth induced by cyclic loading, which is consistent with the measured increase in average pore size and porosity [31]. The whole tendency of the specific surface goes up, which physically means that the total surface area of pores increases.…”

Investigation of Barrier Inhomogeneities and Electronic Transport on Al-Foil/p-Type-4H-SiC Schottky Barrier Diodes Using Diffusion Welding

“…In particular, the promising properties of p-type 4H-SiC have not yet been accomplished to their full potential for use in the fabrication of highly efficient power devices depending on the quality of the SiC layers and metal-SiC contacts. The contact formation process for soldering and attaching dies, (e.g., micro or nanoparticle pastes or solders) and their thermal stability as Schottky contacts have been studied to realize their operational requirements and to improve the performance of SiC-based devices [8][9][10][11]. Direct bonding (DB) technology has significant attention in the development of power electronics and micro electromechanical systems [12].…”

Measurement of Heat Dissipation and Thermal-Stability of Power Modules on DBC Substrates with Various Ceramics by SiC Micro-Heater Chip System and Ag Sinter Joining

“…Since these WBG semiconductors have superior properties, kind of a wide band gap (>3 eV), a high critical electric field (>3 MV/cm) and a high saturation velocity (>2 × 10 7 cm/s), SiC and GaN can enable to overcome the ultimate performances reached by silicon (Si) based devices, in terms of power conversion efficiency [3]. In addition, WBG semiconductor devices can be operating much higher temperatures (>250 °C) than Si based devices (<150 °C) [4,5,6,7,8], this means massive, complex and heavy cooling systems can be eliminated from power conversion systems. Inverters and converters automotive components can be change to smaller by the simply heat dissipation design of in the high temperature environments [9].…”