高性能金屬閘極低溫多晶矽薄膜電晶體之研究

Abstract

本論文將金屬閘極整合到使用高介電係數介電質的多晶矽薄膜電晶體上。我們選用鐿(擁有最低功函數的鑭系金屬,約2.6電子伏特)在NMOS上。我們得到了良好的薄膜電晶體的特性，例如，低臨界電壓、高驅動電流、低次臨界斜率、高閘極介電層崩潰電壓、以及很好的開關電流比例。這些良好的特性是因為擁有低功函數的鐿可以成功的將臨界電壓降低，還有高介電係數介電層閘極可以得到較薄的等效氧化層厚度。而本論文之研究不是用特殊的成晶步驟，我們只用了爐管來成晶就可以達到。

We have integrated a Metal gate into Poly-Silicon (LTPS) thin-film transistors (TFTs) with high – κ gate dielectric. We use Ytterbium ( Yb , has the lowest work-function in Lanthanide series metal≒ 2.6 eV ) for NMOS. We get good TFT performance in NMOS, such as a low threshold voltage, a high drive current, a low subthreshold slope, high gate–dielectric breakdown voltage, and a very good on/off current ratio. The good performance is related to the low work-function metal, Ytterbium, makes the threshold voltage lower successfully and small equivalent oxide thickness by high κ dielectric material. This was achieved without special crystallization steps, we only use furnace to crystallize.