Generation and Annealing of Crystalline Disorder in Laser Processing of Silicon

Abstract

The laser-induced crystalline disorder in silicon has attracted increasing interest due to its impact on the device performance of Si-based solar energy, optoelectronic, and electronic devices. Combined experimental and simulation approaches are effective for investigation of the fundamental mechanisms responsible for the formation of amorphous phase, polycrystalline structure, and crystal defects in the course of laser processing. In this chapter, the effects of laser pulse duration, wavelength, and fluence on the spatial distribution and concentration of point defects and dislocations, as well as the thickness and morphology of amorphous regions, are discussed based on the results of computer modeling and experiments. The laser-based thermal annealing is also considered as an effective technique for mitigating the laser-induced disorder. Overall, this chapter provides an up-to-date review of the disorder generation in laser-processed silicon and highlights the laser annealing technique for the disorder removal in silicon photovoltaic, optoelectronic, and electronic devices.

Single Femtosecond Laser-Pulse-Induced Superficial Amorphization and Re-Crystallization of Silicon

“…Upon irradiation of semiconductors with ultrashort (fs-ps) laser pulses, amorphous surface layers with a thickness of some tens of nanometers were reported, as determined by analytical techniques such as transmission electron microscopy (TEM), electron backscatter diffraction (EBSD) analyses, micro-Raman spectroscopy (µ-RS), confocal scanning laser microscopy (CSLM), real-time reflectivity measurements (RTR), and fs-time-resolved microscopy (fs-TRM) [ 33 , 34 , 36 , 37 , 38 , 39 , 40 , 41 , 42 , 43 , 44 , 45 , 46 , 47 ]. The specific interest of such a contact-less surface modification technology is based on the remarkably different structural, electrical and optical properties of the amorphous and the crystalline silicon phases that enable applications in electronics and photonics and manifest through alterations of the local chemical etching rate, electric conductivity, or the high refractive indices at telecom wavelengths [ 48 , 49 ].…”

“…Therefore, kinetic aspects are linked to the specific laser irradiation conditions. Here, the reader is referred to pertinent literature, including thermodynamic and atomistic numerical studies [27,29,32,[34][35][36].…”