Dislocation Generation at Si3 N 4 Film Edges on Silicon Substrates and Viscoelastic Behavior of SiO2 Films

Abstract

The relation between the force acting on SijN4 film edges and dislocation generation in silicon substrates under the SisN4 film edge is investigated. Samples with 3 • 3 mm square patterns of SijN4 are annealed at 600~176 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 SijN4 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 SisN4-SiO~ films. A thin SiO2 film inserted between the SisN4 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.In silicon device technology, chemical vapor deposited (CVD) Si3N4 films on silicon substrates have Key words: stress, mechanical property, x-ray section topography.been widely used as selective oxidation masks. It is well known that SigN4 films on silicon substrates have a tensile stress of about 109 N/m2 at room tern- perature (1-3). The origin of this stress is not ) unless CC License in place (see abstract). ecsdl.org/site/terms_use address. Redistribution subject to ECS terms of use (see 141.210.2.78 Downloaded on 2015-05-30 to IP * Electrochemical Society Student Member. * * Electrochemical Society Active Member. Key words: poiycrystaUine silicon, low pressure chemical vapor deposition, phosphorus, ion implantation. ) unless CC License in place (see abstract). ecsdl.org/site/terms_use address. Redistribution subject to ECS terms of use (see 141.210.2.78 Downloaded on 2015-05-30 to IP

Effects of the etchmask properties on the anisotropy ratio in anisotropic etching of silicon in aqueous KOH

“…This phenomenon is well known from the LOCOS process [19][20][21] where it appears as the so called bird's beak. Due to the possible defect generation in the monocrystalline silicon [20,[22][23][24] it can be assumed that this mechanical stress also influences the etch attack of the silicon to be etched.…”

Reduction of dislocation density in Si by thermal cyclic annealing

“…The glide motion of dislocations is controlled by the frictional force acting on the dislocations, and the climb motion by the interaction with vacancies. At such a high temperature as just below the melting point the frictional force acting on the glide dislocations is expected to be very small even in Si where the Peierls force is very high [8]. Thermal cyclic annealing increases the opportunity of dislocations interacting with vacancies, thus enhancing the climb motion of dislocations.…”

Defect Characteristics and Generation Mechanism in a Bird Beak Free Structure by Sidewall Masked Technique

“…It is also well k n o w n that SisN4 stress to the silicon substrate can be reduced by inserting a thin SRO between Si3N4 and silicon substrate. The stress is reduced by the viscoelastic behavior of SRO (11,12). Empirical rule indicates that a sufficiently thick SRO can be used to minimize the probability of dislocation generations.…”