為了改善MOSFET電晶體的性能，元件的尺寸被要求越來越小，許多新穎的研究成果已被發表出來，其中，高功函數金屬閘極的研究相當引人注目。
本論文研究的重點放在高功函數金屬閘極的材料選擇上。第一部分為研究兩種以MoN為主搭配TiN薄膜的閘極堆疊結構搭配high-k介電層材料 HfAlO，其中TM_H (TiN/MoN) 閘極在經過高溫退火之後，閘極金屬的擴散並不明顯，故其在可靠性上的表現特別優良。第二部分為探討新的單層金屬閘極WN，並整合在介電層分別為SiO2和ALD沉積的high-k介電層上，單層WN閘極不論在電性上和還是熱穩定性上的表現均較單層MoN來的好，WN_S(WN_SiO2) 閘極在經過高溫退火之後，閘極金屬的擴散並不明顯，故其在可靠性上的表現特別優良。整體來說單層WN閘極有良好的電特性相較於單層MoN金屬閘極元件。而在功函數的熱穩定性上，WN閘極的熱穩定性經過高溫退火後仍保有其高功函數的特性，皆擁有還不錯的功函數熱穩定性，雖然高溫後有有所下降，但皆仍高於5.0 Ev所以適合於pMOS元件的應用。
第三部分的討論中我們承接第二部分的結論，而且為了想要獲得更佳品質的金屬閘極條件，我們加入了Hf，使之成為合金WxHfN合金式金屬閘極，發現以WHfN合金當作閘電極所形成的元件具有極佳的電特性和熱穩定性，最主要是因為此條件下的金屬離子具有最輕微的擴散深度且擴散的情形較不受PMA溫度影響。最後，在第四部分繼續延續上一部份WHfN合金當作閘電極，本章主要討論WHfN金屬閘極搭配high-k介電層，希望找出最合適的合金式金屬閘極、以及high-k介電層結構，得知WHf50_H(W:50w)合金式金屬閘極搭配 HfO2/HfAlO 堆疊式介電層，可以達到最佳化的高功函數metal gate/high-k dielectric金氧半元件。

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