This present procedure offers a boost in efficiency and productivity of laser-based amorphous semi-conductor anneling processes. This increase in efficiency is realized by interaction of a homologously shaped laser beam with a standard pressure plasma, e.g. a plasma layer, in direct proximity to the material surface.
For an efficient and cost-effective production of displays with screen diagonals larger than 42 inch using the Low Temperature Poly Silicon (LTPS) method, it is necessary to realize the a-Si cristallization process as homogenous and on an as large as possible area, with as low energy intake of the carrier material as possible. The goal of this invetion was therefore, to maximize the conversion of laser energy into thermal energy within the semiconductor layer, to enable a large-scale processing without costly optics and high-power lasers.
It was shown that a standard pressure plasma interacting with both the laser and the semiconductors surface during a laser-based LTPS annealing process was able to significantly boost efficiency of laser-to-thermal-energy conversion within the exposed substrate. It is at the same time beneficial, when the thickness of the plasma layer is kept below 5 mm and the electron density significantly below the cut-off for the corresponding laser wave length, to keep energy losses due to interactions between the laser beam and the plasma below 1 %.
LTPS-setup with remote plasma. U: high voltage source with alternating current.
Production of large-scale technical components based on polycristalline silicon, such as Thin-Film Transistors (TFT).
Increase in Generation of Poly-Crystalline Silicon by Atmospheric Pressure Plasma-Assisted Excimer Laser Annealing, Gredner et al., Journal of Materials Science and Engineering (2013).
Plasma-Enhanced Laser Materials Processing, Gerhard, Viöl, Wieneke, (2016), DOI: 10.5772/61567
Dr. Ireneusz Iwanowski