Characterization of amorphous and nanostructured Si films by differential scanning calorimetry

• Published in: Thin solid films Vol. 517; no. 23; pp. 6239 - 6242
• Main Authors: Roura, P., Farjas, J., Roca i Cabarrocas, P.
• Format: Journal Article Conference Proceeding
• Language: English
• Published: Amsterdam Elsevier B.V 01.10.2009; Elsevier
• Subjects: Composition and phase identification; Condensed matter: structure, mechanical and thermal properties; Cross-disciplinary physics: materials science; rheology; Crystallization; Dehydrogenation; Diffusion; interface formation; DSC; Exact sciences and technology; Hydrogenated silicon films; Materials science; Nanoscale materials and structures: fabrication and characterization; Other topics in nanoscale materials and structures; Physics; Solid surfaces and solid-solid interfaces; Surfaces and interfaces; thin films and whiskers (structure and nonelectronic properties); Thermal properties of condensed matter; Thermal properties of crystalline solids; Thermodynamic properties; Thin film structure and morphology; Hydrogenated silicon films; DSC; Dehydrogenation; Crystallization; Differential scanning calorimetry; Temperature dependence; Crystalline phase; Phase transformations; Enthalpy; Epitaxy; Nanostructures; Structure relaxation; Thin films; Reviews; Hydrogen bonds; Temperature effects; Experimental design; Silicon; Diffusion; Microstructure; Thermodynamic properties; Nanostructured materials; Nanocrystal
• ISSN: 0040-6090; 1879-2731
• DOI: 10.1016/j.tsf.2009.02.081

Over the last 5 years, we have successfully applied differential scanning calorimetry (DSC) to study silicon thin films. The aim of this paper is to review our main results to give an overview of the possibilities offered by this technique, which is widely used to characterize solid state transformations. We will address some classical subjects related to the structure of pure and hydrogenated a-Si, such as the strength of the Si–H bond, hydrogen diffusion and the contribution of structural defects and strained bonds to the enthalpy of structural relaxation and crystallization. Special attention will be paid to the crystallization kinetics of films with structures ranging from pure amorphous to highly crystalline. Despite previous expectations, in films deposited at low temperature, the presence of nanocrystals embedded in the amorphous phase does not promote crystallization. In fact, the crystallization temperature is much higher than expected from a simple solid state epitaxy mechanism, which indicates low coupling between the amorphous and crystalline phases.