An atomistic growth model is used to explain sidewall facet and defect formation during selective epitaxial growth of (001) silicon. Films grown through oxide windows with {110} sidewall orientations exhibit facets (typically {311} planes) adjacent to the sidewall. This region also has a high density of twins. Films grown in windows oriented to have {100} sidewalls have no sidewall facets and a very low defect density. The facet morphology and twin formation at {110} sidewalls are both explained by the influence of the oxide on nucleation of {111} planes. Similar considerations indicate that films grown along {100} sidewalls are less susceptible to facet and defect formation, as observed. Experimental data on film morphology and defect structure are used to support the model.

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Although laser recrystallization of polysilicon into a large-grain structure degrades the lifetime in the underlying substrate, a subsequent heat treatment similar to that seen during transistor fabrication increases the lifetime to approximately the value in the regions not laser processed. KO electrical effects of laser damage to the underlying substrate are found in the transient behavior of MOS capacitors after furnace annealing or in the properties of p A n junction diodes. Since any damage to the substrate during laser processing is substantially eliminated by subsequent heat cycles, recrystallization is compatible with fabrication of high-quality devices in the substrate.

We report on the ability of ellipsometry to rapidly determine the germanium content and the film thickness of Si1−xGex layers deposited on silicon substrates. The technique is used to evaluate thickness on single- and for the first time, double-layer Si/SixGe1−x films. We estimate the refractive index of Si1−xGex from ellipsometry measurements and find that only the real part differs significantly from that of silicon for 0<x<0.30. We examine the sensitivity of ellipsometry to changes in germanium content and film thickness. We find that sensitivity is cyclical with film thickness and, in the best case, ellipsometry can be used to determine germanium content within ±1 at. % or thickness within ±20 Å for x∼0.10.