Silicon carbide (SiC) power devices have been expected as next‐generation power‐saving devices. We succeeded in fabricating very large area (1 cm2) SiC Schottky barrier diodes (SBDs) with forward current of 300 A by inactivating areas including crystal defects. Heterojunction diodes with avalanche energy of over 2000 mJ/cm2 were also developed. The reliability of gate oxide films of SiC DMOSFETs was enhanced to a level that is comparable to silicon power devices by improving oxidation techniques. We succeeded in fabricating SiC trench MOSFETs with low on‐resistance (1.7 mΩ cm2). 250 °C operation of intelligent power modules (IPMs) with SiC DMOSFETs was achieved by using a new attachment technology. (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)

The high current SiC MOSFETs and hightemperature operation IPM with SiC MOSFETs were fabricated. 300A switching in inductive load circuits was performed using a single chip SiC trench MOSFET. And 250 o C (the junction temperature of SiC DMOSFETs) operation of SiC IPMs with a new high-temperature bonding method and high-temperature materials (case, encapsulation) was successfully performed.

This paper investigates the porosity-dependent tensile mechanical properties of porous silver films that are 8-10 μm thick. The silver films are fabricated with a pressure press; the use of different pressures changes the porosity (p) in the range of 5% to 25%. p is determined using scanning electron microscopy cross-sectional images of the films. Stress-strain (S-S) curves are obtained by tensile tests performed on the porous and bulk silver films. The conventional ductile plateau disappears from the porous films. Augmented ultimate tensile strength and a smaller breaking strain occur when p is in the range 6%-14%.

This paper investigates the influence of temperature on tensile mechanical properties of sintered silver (s-Ag) films with 8–10 μm in thickness for fundamental reliability design of semiconductor systems. The s-Ag film sintered under a pressure of 60 MPa possesses the porosity (p) around 5% determined from cross-sectional scanning electron microscope (SEM) images. The stress–strain (S-S) curves of s-Ag and pure silver (p-Ag) films are obtained using originally designed uniaxial tensile tester at temperatures from 25 °C to 150 °C. The S-S curves of p-Ag indicate ductile behavior irrespective of temperature, whereas those of s-Ag indicate brittle-ductile transition at 120 °C. Compared with p-Ag, s-Ag possesses low Young’s modulus (E) and high ultimate tensile strength (UTS) below 80 °C. The mechanism of brittle-ductile transition is discussed based on fracture surface observation results.

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