Power SDB-devices with regularly grooved interfaces

We have proposed a novel modification of silicon direct bonding (SDB) technique dealing with silicon wafers joined in such a way that a smooth surface of one wafer is attached to the grooved surface of the other. This paper presents some experimental data related to devices based on the developed SDB-technique. By the method employing a regularly grooved interface, continuously bonded void-free P-N, P-P and N-N-structures with the initially misoriented wafers were fabricated and examined. Mapping the series resistance of I-V-curves on 60 mm diameter bonded structures demonstrated the absence of pronounced interfacial defects all over the operating area. By using the capacitance spectroscopy (DLTS) method it was shown that the deep level center concentration in the vicinity of bonded interface in the grooved-smooth structures is one order of value lower than in the conventional smooth-smooth SDB-structures.