Novel bridged-grain (BG) technique is applied in the fabrication of low-temperature solid-phase-crystallized polycrystalline-silicon thin-film transistors. As a result of improved current flow and reduction of high drain electric field, the subthreshold slope, threshold voltage, maximum field-effect mobility, leakage current, and on-off ratio are greatly improved. Mechanisms of BG conduction are studied in detail.Index Terms-Bridged grain (BG), polycrystalline silicon (poly-Si), thin-film transistors (TFTs).

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Polycrystalline silicon (poly-Si) films consisting of dish-like and wadding-like domains were obtained with solution-based metal-induced crystallization (SMIC) of amorphous silicon. The Hall mobility of poly-Si was much higher in dish-like domains than in wadding-like domains. Thin-film transistors (TFTs) have been prepared using those two kinds of poly-Si films as the active layer, followed by the phosphosilicate glass (PSG) nickel gettering. The field effect mobility of dish-like domain poly-Si TFTs and wadding-like poly-Si TFTs were 70 80 cm 2 V s and 40 50 cm 2 V s, respectively. With a multi-gate structure, the leakage current of poly-Si TFTs was reduced by 1 to 2 orders of magnitude. In addition, the gate-induced drain leakage current (GIDL) and uniformity of the drain current distribution were also improved. P-type TFTs fabricated using SMIC exhibited excellent reliability. Index Terms-Metal-induced crystallization (MIC), nickel gettering, polycrystalline silicon (poly-Si), thin-film transistors (TFTs). I. INTRODUCTION W HILE most active matrix liquid crystal displays (LCDs) are made of amorphous silicon (a-Si) thin-film transistors (TFTs), there is always a demand for polycrystalline silicon (poly-Si) based active matrix displays because the latter can provide much higher resolution and smaller pixels. As well, some of the driver circuitry can be integrated onto the glass substrate in the case of poly-Si TFT. Additionally, the p-Si TFT is more stable than a-Si TFT in terms of driving organic light emitting diode (OLED) displays. Thus low cost, high performance and reliable low temperature poly-Si (LTPS) processing technologies are greatly required [1], [2]. Poly-Si films with large crystalline grains have been obtained using the techniques of excimer laser annealing (ELA) [3] and metal-induced crystallization (MIC) [4]. There are several Manuscript