Grain alignment in poly-Si films by means of Plasma Immersion Ion Implantation (PIII) in combination with Flash Lamp Annealing (FLA)

A series of experiments have been performed with the aim to improve the electrical and structural properties of CVD – deposited thin polycrystalline silicon films. Using an advanced ion implantation technique like Plasma-Immersion-Ion- Implantation (PIII) in combination with short time Flash-Lamp-Annealing (FLA) it has been shown that in comparison to the as deposited state a significant enlargement of the mean grain size occurs, accompanied by a more pronounced texturizing. Furthermore, the main crystallographic axes of the grains have been found to be mostly parallel to the direction of the particle stream. Whereas the enlargement of the mean grain size due to ion channelling was already reported by Reif et al. in the 80s, in the present work the SSIC technique (Seed Selection though Ion Channelling) was applied for the first time using the PIII process. This technique ensures a high throughput; additionally the costs for the implantation step can be reduced in comparison to conventional ion implantation. Furthermore, in contrast to the well known existing recrystallization techniques like cw-laser annealing or lateral zone melting recrystallization (ZMR), the proposed method circumvents problems arising from several mass transports characteristics of techniques based on melt processes.