Step-by-step excimer laser induced crystallization of a-Si : H

Amorphous silicon films (a-Si:H) with a hydrogen content of 10 at. % were c rystallized employing a step-by-step crystallization method. Structural cha nges during the sequential crystallization process were monitored by Raman spectrometry. Initially, at low laser fluences E-L, a two-layer system is c reated. Independent of the thickness of the a-Si:H layer explosive crystall ization of a thin surface layer is observed at E-L greater than or equal to 100 mJ/cm(2) confirming recent theoretical results. Crystallization is acc ompanied by dehydrogenation. In completely crystallized poly-Si a residual H concentration of up to 5 at. % was observed. (C) 2000 American Institute of Physics. [S0003-6951(00)04513-7].