Laser annealing of silicon nanocrystal films formed by pulsed-laser deposition

Abstract

We report the laser annealing effects on the structures and properties of silicon nanocrystal films fabricated by pulsed-laser deposition in inert argon gas. The surface morphology of the as-deposited films is greatly determined by the angle relative to the laser ablation spot. Photoluminescence ͑PL͒ peaked at 620 nm corresponding to 2.0 eV is observed in the as-deposited films. After single-pulse laser annealing, better crystallinity and increased PL intensity are obtained. The PL peak remains at 620 nm. High laser fluence causes damage to the films and the threshold fluence for laser ablation is around 100 mJ/cm 2 . Multiple-pulse laser annealing with increasing pulse number at fluences below the threshold of laser ablation can provide better crystallization and property improvement than single-pulse annealing. There are a certain number of pulses for the best multiple-pulse annealing effect before damage or laser ablation occur.

Ultrafast crystallization kinetics in (Pb,La)(Zr0.30Ti0.70)O3 thin films by pulsed excimer laser annealing

“…Techniques such as laser annealing [5] and high-energy ion or e-beam assisted [6] crystallization have been employed to crystallize thin films without overheating the underlying substrates. Indeed, laser annealing enables crystallization of silicon with controlled doping, microstructure, and electrical properties [7], [8].…”

Excimer Laser Crystallized (Pb,La)(Zr,Ti)O3 Thin Films

“…Alternative methods such as laser‐assisted crystallization 5 and high energy ion or e‐beam assisted crystallization are well known in the semiconductor industry as methods of achieving localized heating 6 . For example, it has been demonstrated that laser annealing enables crystallization of amorphous silicon with controlled doping, microstructure, and properties on various substrates at low substrate temperatures 7,8 .…”

Theoretical Study on Laser Annealing of Non-Stoichiometric SiOX films

“…Temperature of the specimen at high irradiation intensity is big enough for stimulating phase transitions of SiO x film into nano-composite film SiO 2 (Si) with silicon nano-crystals [16][17][18]. Analysis of laser annealing influence on nanocrystalic silicon films produced in environment of inert gas argon [17] shows that one-and manypulsed laser annealing improves crystallinity in films. (1) The graphs of Fig.…”

“…The temperature of the sample in the center of the laser beam at high intensity of laser irradiation is enough to stimulate the phase transition of SiO x film into nanocomposite SiO 2 (Si) film with Si nanocrystals [14]. It was shown [17] that at the temperatures of 1470 and 1620 K the Si nanocrystals were formed during 1 s and 20 ms respectively. Although the surface temperature of the sample between laser beams increases with decreasing distance between the beams but it is not enough to stimulate the phase transition of SiO x film into nanocomposite SiO 2 (Si) film with Si nanocrystals which agrees well with the experimental data obtained in [19].…”