DEFLECTED STATE OF SEMICONDUCTOR NEAR-CONTACT REGION AT ELECTRODEGRADATION OF METALLIZATION TRACK ON ITS SURFACE

Abstract

It is well known that a nonhomogeneous state of stress occurs in compounds of dissimilar materials upon heating. Uon the assessment of the strength of the joints, it is necessary to factor in the physical specifications of the soldered elements, the geometric dimensions and temperature conditions of their operation. The purpose of the research was to perform the stress-strain state analysis of the contact zone of a semiconductor upon electrodegradation of a metallization track on its surface. Thin-film metal-semiconductor structures were researched. As substrates, it was used phosphorus-doped silicon single-crystal wafers oriented in the (111) and (100) directions, with a resistivity in the range p = 1 ... 0.01 Ω.cm, and a 30 ... 50 μm n-epitaxial layer was deposited on a part of the wafers. As a conductive metal film, aluminum 1 ... 2 μm thick was used. The test structure was formed by optical photolithography. The oscillograms of the U(t) inclusion in the process of passage of the current pulse were taken by the corresponding probes from potential sites and recorded by a digital storage oscilloscope. An estimation procedure for the semiconductor stressed region at local surface heating of a metallized surface area with electric pulse was given. The calculated size of deformed silicon substrate region was compared with the experimental one under passage of square electric pulses. It was estimated the deflected region that depends on duration and amplitude of electric pulse. A considerable nonuniformity of the metallization track after electric pulse passage was fixed experimentally.