Due to their process requirements being similar to the making of amorphous silicon thin-film transistors (TFTs) and their relatively higher field-effect mobility (μFE), metal-oxide (MO) TFTs are being deployed in the construction of flat panel displays. The elevated-metal MO (EMMO) TFT technology, based on the distinct effects of oxidizing thermal annealing on the properties of MO semiconducting films under covers of different gas-permeability, reveals promising prospects. This thesis is aimed at studying the architecture modification and material engineering of EMMO TFTs in advanced flat-panel displays (FPDs). By establishing and analyzing a design model through pixel charging and delay propagating in the active-matrix (AM) displays, it is found that the development of EMMO tec...[ Read more ]

Due to their process requirements being similar to the making of amorphous silicon thin-film transistors (TFTs) and their relatively higher field-effect mobility (μFE), metal-oxide (MO) TFTs are being deployed in the construction of flat panel displays. The elevated-metal MO (EMMO) TFT technology, based on the distinct effects of oxidizing thermal annealing on the properties of MO semiconducting films under covers of different gas-permeability, reveals promising prospects. This thesis is aimed at studying the architecture modification and material engineering of EMMO TFTs in advanced flat-panel displays (FPDs). By establishing and analyzing a design model through pixel charging and delay propagating in the active-matrix (AM) displays, it is found that the development of EMMO technology should focus on the improvement of inner mobility, decreasing feature size and reducing parasitic capacitance to aid its competitiveness in advanced FPDs.

The dependence of the annealing behaviors of the resistivity of indium-tin-zinc oxide (ITZO) film on gas-permeability is studied. ITZO-based EMMO TFTs have been realized and characterized. Good performance metrics, such as a relatively high μFE of above 20 cm²/Vs, transfer characteristics free of hysteresis and a low width-normalized off-state leakage current of at most 8.1×10^-19 A /μm were obtained.

With the more effective method of combining the fluorination and oxidation on passivating oxygen vacancy defects, a thermally oxidized fluorinated MO channel is the optimized combination to improve the transistor scalability and reliability. By controlling the “lateral” oxidation in the homojunction, sub-micron short channel EMMO TFTs have been realized and characterized.

With the study of the dependence of the migration of an annealing-induced junction in MO, the self-aligned EMMO architecture is proposed and achieved by employing a back-side flood exposure step with annealing-induced junctions self-aligned to the edges of the gate electrode. While offering the same small parasitic capacitance, the self-aligned EMMO technology further allows full oxidation of the channel region, thus improving the performance and reliability of the transistor.