Summary: | This thesis presents my work on the fabrication of nanocrystalline silicon (nc-Si) thin film transistors and characterization of their stability under different conditions. Nc-Si transistors are promising alternative to the current amorphous silicon (a-Si:H) devices, especially in areas where a-Si:H TFTs are reaching the performance ceiling, e.g. new large area applications such as active matrix organic light emitting diode displays (AMOLED). This is mostly due to the superior nc-Si properties – high carrier mobility and good electrical stability stemming from the crystalline Si grains embedded in a disordered a-Si:H matrix. Another large advantage of nc-Si TFTs over competing materials is the full compatibility with the a-Si:H fabrication base. Nanocrystalline silicon is a relatively new material and some aspects require further investigation before industrial applications. The pool of knowledge on nc-Si devices is especially shallow for the electrical stability of bottom gate TFTs under prolonged illumination which is important for several thin film applications, such as AMOLED and phototransistors. This issue was selected as the main topic of the thesis. Top gate TFTs were also designed, fabricated, characterized and compared to the bottom gate transistors. The electrically detected magnetic resonance method was employed to investigate the nc-Si/dielectric structures and it was shown that it can be used to evaluate the TG TFT channel/dielectric interface.
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