Thin polycrystalline SiGe films by aluminium‐induced layer exchange

Abstract

Recent results concerning the aluminium-induced crystallization of thin SiGe alloy films are reviewed. This crystallization process can be employed throughout the entire alloy range and results in polycrystalline material without a significant amount of phase separation. The structural, optical, and electronic properties of the polycrystalline SiGe films have been determined by a variety of techniques and for different Ge contents. The use of such films in thin film solar cells is discussed.

Germanium(cF136): A New Crystalline Modification of Germanium with the Porous Clathrate‐II Structure

“…[5] This rather astonishing result is of major importance, since nanostructured germanium (possibly in combination with silicon) offers a promising alternative to established materials in photovoltaics and in silicon-based optoelectronic building blocks. [6][7][8][9] In addition to the well-known a form of germanium with the diamond structure (Ge-I, Ge(cF8)), several highpressure modifications of germanium have been structurally characterized. [10] In Table 1, the germanium structures determined at atmospheric pressure and that of b-Ge at 120 kbar are compared.…”

Structural and thermoelectric properties of SiGe/Al multilayer systems during metal induced crystallization

“…7(a [23] to an increase in crystallization rate assisted by the occurrence of a liquid phase. As both Si and Ge form a eutectic system with Al, a liquid phase can be expected for temperatures higher than the respective eutectic temperatures T eut,SiAl = 850 K and T eut,GeAl = 693 K in such systems [13]. The saturation of T MIC,2 of about 720 K is very close to the eutectic temperature of the GeAl system.…”

Hydrogen passivation of ultra-thin low-temperature polycrystalline silicon films for electronic applications

“…Besides laser-annealing, metal-induced methods for crystallization of amorphous silicon are gaining importance for this purpose. Here, the aluminum-induced layer exchange (ALILE) process is a promising method to obtain large-grained high quality polycrystalline Si [4] and SiGe [5,6] films at low process temperatures. In a typical ALILE process an Al/amorphous Si (a-Si) layer stack, separated by a thin oxide film, is annealed at temperatures below the eutectic temperature of the Al-Si system, leading to a layer exchange and the crystallization of the a-Si.…”