During the thermal aging process of epoxy resin, microcracks, interfacial delamination, and warpage are the key factors leading to semiconductor device damage. Here, epoxy-resin specimens (EP-Ss) and epoxy-resin/silicon-wafer composites (EP-SWs) were prepared to analyze the distribution of residual stress (RS) in epoxy resin and its thermal aging process changes. The uniaxial tensile approach and Raman spectroscopy (RAS) showed that the peak shift of aliphatic C-O in EP-Ss was negatively correlated with the external stress, and that the stress correlation coefficient was −2.76 × 10⁻² cm⁻¹/MPa. Then, RAS was used to evaluate the RS distribution of EP-SWs, obtaining a high-resolution stress-distribution image of 50 × 50 pixels and revealing a strong stress concentration at the interface between the epoxy resin and the silicon wafer. Additionally, Fourier transform infrared spectroscopy (FTIR), Differential scanning calorimetry (DSC), Field-emission scanning electron microscopy (FE-SEM), and RAS were used to analyze the chemical composition, molecular structure, interfacial microstructure, and RS of the epoxy resin during the thermal aging process. With the increase in the thermal aging time, the epoxy resin underwent secondary curing, the RS at the interface changed from tensile stress to compressive stress, and cracks were formed. The results illuminate the effect of the thermal aging process on the interface-failure mechanism of composite materials, aiding in the reliability evaluation and safety design of semiconductor devices.

In this work, the influences of special environments (hydrogen gas and high temperature, high humidity environments) on the performance of three types of SiC MOSFETs are investigated. The results reveal several noteworthy observations. Firstly, after 500 h in a hydrogen gas environment, all the SiC MOSFETs exhibited a negative drift in threshold voltage, accompanied by an increase in maximum transconductance and drain current (@ V_GS/V_DS = 13 V/3 V). This phenomenon can be attributed to that the hydrogen atoms can increase the positive fixed charges in the oxide and increase the electron mobility in the channel. In addition, high temperature did not intensify the impact of hydrogen on the devices and electron mobility. Instead, prolonged exposure to high temperatures may induce stress on the SiO₂/SiC interface, leading to a decrease in electron mobility, subsequently reducing the transconductance and drain current (@ V_GS/V_DS = 13 V/3 V). The high temperature, high humidity environment can cause a certain negative drift in the devices’ threshold voltage. With the increasing duration of the experiment, the maximum transconductance and drain current (@ V_GS/V_DS = 18V (20 V)/3 V) gradually decreased. This may be because the presence of moisture can lead to corrosion of the devices’ metal contacts and interconnects, which can increase the devices’ resistance and lead to a decrease in the devices’ maximum transconductance and drain current.

The cohesive performance and durability of the bonding layer with semiconductor substrates are of paramount importance for realizing the high thermal conductivity capabilities of diamond. Utilizing electron beam evaporation and the room-temperature, low-pressure bonding process, robust adhesion between diamonds and silicon substrates has been achieved through the application of the metal modification layer comprised of Ti/Cu/Ti/Au (5/300/5/50 nm). Characterization with optical microscopy and atomic force microscopy reveals the uniformity and absence of defects on the surface of the deposited layer. Observations through X-ray and scanning acoustic microscopy indicate no discernible bonding defects. Scanning electron microscopy observation and energy-dispersive spectroscopy analysis of the fracture surface show distinct fracture features on the silicon substrate surface, indicating that the bonding strength of the Ti/Cu/Ti/Au metallization layer surpasses that of the base material. Furthermore, the fracture surface exhibits the presence of Cu and trace amounts of Ti, suggesting that the fracture also occurs at the interface between Ti and Cu. Characterization of the metal modification layer using X-ray diffraction reveals significant lattice distortion in the Ti layer, leading to noticeable stress accumulation within the crystalline structure. Thermal–mechanical fatigue simulations of the Ti/Cu/Ti/Au metal modification layer indicate that, owing to the difference in the coefficient of thermal expansion, the stress exerted by the Cu layer on the Ti layer results in the accumulation of fatigue damage within the Ti layer, ultimately leading to a reduction in its strength and eventual failure.