Quantified Conditions for Emitter‐Misfit Dislocation Formation in Silicon

Abstract

The conditions under which misfit dislocations are generated during phosphorus diffusion in silicon are discussed. Van der Merwe's concept of critical misfit is used to determine the critical surface region depth for a given P surface concentration which causes spontaneous misfit dislocation formation. Using this model the times required to form misfit arrays are calculated as a function of temperature and surface concentration. The effect of misfit dislocation generation in an oxidizing ambient is also discussed.

On the Kinetics of the Thermal Oxidation of Silicon: II . Some Theoretical Evaluations

“…Thus, the transition is from a distributed strain energy throughout the film to a localized defect energy at the interface. This same effect is observed as a result of the constitutional strains developed as a result of the diffusion of n-type or p-type dopant into Si from the surface layer (5,6). At low doping levels, the strain is not sufficient to cause the transition to dislocation net formation; whereas, above a predictable condition (6), the dislocation net appears.…”

“…Thus, in the absence of complete mass transfer control, the current density is not uniform across the disk radius due to the ohmic potential drop in solution. Newman (6) and Nanis (7) have elaborated on this problem and Newman (6) has shown that the current density at the center can vary between 50 and 100% of the average current density. The distribution in current density under these conditions implies a distribution in potential across the disk radius, and consequently a distribution in electrochemical state.…”

“…Perhaps the most interesting feature to note about these results is that the electric field effect, which enhances the ionic transport, enters the formal solution as modified kinetic coefficients k*' : Dik*/b; h*' -~ Dih*/a [6] as well as an altered parabolic rate constant. Thus, changing tim Si doping level, such that the Fermi energy moves away from midband at the oxidizing temperature, should alter the magnitude of a and thus both the linear and the parabolic rate constants.…”

“…case, the modified kinetic coefficients (Eq. [6]) depend on both the Fermi level effect via ~ and the partial pressure of oxygen in the gas phase.…”

Direct growing of lightly doped epitaxial silicon without misfit dislocation on heavily boron-doped silicon layer

“…However, misfit dislocations which can degrade electronic properties ͑especially, increase junction leakage current͒ are frequently generated in the epitaxial p layer due to in-plane lattice mismatch between the p layer and p ϩ layer. 3,5 Thus, elimination of misfit dislocations in the epitaxial layer is very important for the successful fabrication of electronic devices in the layer.…”