Sil_~Ge~ films deposited by very low pressure chemical vapor deposition (VLPCVD), with and without plasma enhancement, and by low-pressure CVD (LPCVD) were studied to explore the effects of Ge on various properties of polySi~_=Ge~ films. As the Ge content increases, growth rates increase for thermal and plasma-deposited polycrystalline and amorphous films. The transition temperature for poly-to-amorphous deposition is lower, and the crystallization of amorphous films is faster. Enlarged grain sizes are achieved with Ge in films grown thermally, with plasma enhancement, and by solid-phase crystallization, with grain sizes as large as 1.3 ~m in films of 1000 A thickness. Increased n-type and p-type Hall mobilities and decreased p-type resistivities are achieved as functions of Ge content in poly-Si~_=Ge~ films with x -< 0.20. The Hall mobility in an n-type poly-Si080Ge0.f0 film is 50 cmf/V-s, the highest value reported to date for poly-Si~_~ Ge~ materials. Poly-Si~ =Gex thin-film transistors (TFTs) have been fabricated and evaluated, leading to a proposal of a poly-Si-capped Si~_=Gez TFT structure.

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Poly-silicon-capped (poly-Si-capped) polysi licon-germanium (poly-Si 1 -,Ge,) thin-film transistors (TFTs) have been designed and fabricated with the aim to improve the performance of load devices in high-density mega-bit SRAM cells. Poly-Si-capped polySil_,Ge, TFTs utilize the excellent interface between oxide and poly-Si interface as well as the higher mobilities of poly-Sil_,Ge,. P-channel poly-Si-capped poly-Sil_,Ge, TFTs show superior device results compared to similarly-processed poly-Si TFTs.

We study the dynamics of a three-dimensional laser bullet propagating inside a nonlinear saturable medium. We show that an increase of the pump parameter destabilizes the bullet and leads to its destruction through oscillations with increasing amplitude. We propose an inhomogeneous and anisotropic external excitation mechanism leading to a stable oscillating bullet. By varying the frequency of the external excitation, a stable quasi-in-phase or quasi-antiphase internal state can be reached.

Polycrystalline-Si1−xGex films have been formed by various methods on oxide-coated Si substrates at temperatures ≤600°C. Compared to thermal growth, plasma deposition of poly-Si1−xGex promotes smoother films with smaller grains having a {200}-dominated texture. Poly-Si1−xGex Alms formed by plasma deposition of amorphous-Si1-xGex followed by a crystallization anneal have an even smoother surface with grain sizes enhanced by an order of magnitude and a weak {111} grain texture. Hydrogen incorporated in amorphous-Si1−xGex evolves completely during crystallization without disrupting the smooth surface morphology. The largest grain sizes (∶1.3μm) are achieved in poly-Si1−xGex films formed by Si+ ion implantation for amorphization with a subsequent recrystallization anneal.