Direct observation of ultra-rapid solid phase crystallization of amorphous silicon films irradiated by micro-thermal-plasma-jet

This paper presents a new method to directly observe the transient evolution of amorphous silicon temperature and the solid phase crystallization during micro-thermal-plasma-jet irradiation. Using the time-resolved reflectivity analysis, nucleation temperature and characteristic crystallization time were determined. When the heating rate increases from to 4.45 x 10(5) to 2.28 x 10(6)K/s, the nucleation temperature increases from 985 to 1071 degrees C. The characteristic crystallization time decreases from 95 to 20 mu s with an increase in heating rate. Crystallization time as a function of temperature corresponds to the activation energy of 2.9 eV. This energy relates to both the nucleation and growth process. Micro-Raman spectroscopy results indicate that the crystalline volume fraction of solid-phase crystallized Si film is higher than 65 %, and it increases to 80 % with decreasing scanning speed. Both high resolution transmission electron microscopy results and theoretical calculation indicate that there is a distribution of final crystal size. The average grain size is smaller than 50 nm and depends on the annealing conditions, namely the faster heating rate is, the smaller grain size is.

Automated summary

This paper introduces a new method to directly observe the transient evolution of amorphous silicon temperature and solid-phase crystallization during micro-thermal-plasma-jet irradiation. The study shows that increasing heating rate leads to higher nucleation temperature and shorter crystallization time. Micro-Raman spectroscopy results reveal a high crystalline volume fraction in solid-phase crystallized Si film, with grain size being smaller for faster heating rates.