Analysis of polydihydrosilane crystallization by excimer laser annealing

Printing of electronics has been gaining a lot of attention over the past decade as a low cost alternative to conventional electronic fabrication methods. A significant development in this area was the possibility to print a silicon precursor, polydihydrosilane, which can directly be transformed into polycrystalline silicon by an excimer laser treatment. Due to the limited laser heat diffusion, low-cost flexible substrates such as plastics and even paper could be used that typically have low thermal budgets. Since the silicon precursor is sensitive to ultraviolet light and may transform in a photochemical reaction, the question arises whether the excimer laser crystallization is predominantly photochemical or rather a thermal reaction. In this work, a model is developed and reflected to experimental data, to understand the physics behind the process. Through finite-element analysis and experimental characterizations it was observed that the physics behind the process was predominantly thermal, and that instead of an intermediate transition to a-Si, a direct transformation to poly-Si exists. By understanding this process, the treatment can be optimized or more efficient tools can be used that would enable a low cost production of high performing silicon devices.