低臨限電壓與高驅動電流之薄膜電晶體在金屬鋁與介電層氧化鑭鉿上之研究

Abstract

本論文將高介電常數的氧化鑭鉿整合至低溫多晶矽薄膜電晶體當作閘極氧化層，並且選用鋁來作為金屬閘極在LTPS上。將可得到高驅動電流、低臨界電壓和低次臨界斜率，大大提升了元件的特性。不僅如此，也因此而達成高的開/關電流比例及閘極崩潰電場。上述所得之優秀的特性與所使用的閘極氧化層種類有密切關係。

使用氧化鑭鉿作為閘極氧化層，可造成高閘極電容密度與很小的等效氧化層厚度。有別於一般的TFT元件，此種元件並不需使用一些介面鈍化處理或是特別的結晶步驟，只需要用爐管就可以達到成晶的目的了。

We have integrated a Metal gate into Low temperature Poly-Silicon(LTPS) thin-film transistors (TFTs) with high-□□□ gate dielectric. We used Aluminum for metal gate, and we used HfLaO for high-k gate dielectric on LTPS. We got high drive current, low threshold voltage and low sub-threshold slop to improve the performance of device obviously. It also achieved high on/off ratio and high gate breakdown electric field. The excellent performances mentioned above are related closely to gate dielectric.

We used HfLaO for high-k dielectric and it can product high density gate capacitor and less EOT. This kind of device is different from other common devices because it is not necessary to apply passive treatment or specific process of crystallization. We only used furnace to crystallize.