DISLOCATION GENERATION AT SI3N4 FILM EDGES ON SILICON SUBSTRATES AND VISCOELASTIC BEHAVIOR OF SIO2-FILMS

The relation between the force acting on Si3N4 film edges and dislocation generation in silicon substrates under the Si3N4 film edge is investigated. Samples with 3x3 mm square patterns of Si3N4 are annealed at 600°-1200°C for 2 hr in N2 atmosphere. The force acting on the film edge is evaluated from the fringe patterns observed in x-ray section topographs. Dislocations generated at the film edge are observed using Secco etching. As a result, it is proved that temperature dependence of a critical force, Sc (N/m), acting on the Si3N4 film edge in dislocation generation is represented by Sc = 10.5 exp (Q/kT), where Q is 0.25 eV. Similar procedures are carried out for samples with Si3N4-SiO2 films. A thin SiO2 film inserted between the Si3N4 film and silicon substrate prevents the formation of dislocations in samples annealed at high temperatures. This suppression effect for dislocation generation is interpreted in terms of the viscoelastic behavior of SiO2 films at high temperatures. © 1979, The Electrochemical Society, Inc. All rights reserved.