本實驗室使用分子束磊晶(MBE)的方法在矽晶片上成長HfO2高介電常數(□ = 15)氧化層，且HfO2與矽晶片之間並無任何的二氧化矽或其它的矽氧化物產生，這是在此領域第一次發現的成果。除此之外，我們利用在Ar/N2的電漿環境中濺鍍鈦的方式來沉積TiN金屬閘極。二段式退火被使用來改善高介電常數金氧半電容(High-□ MOSCAP)的電特性，界面間的能量態密度(Dit)經Terman method計算約為1E12 ev-1cm-2。而TiN/HfO2閘極層之熱穩定性也將在本論文中探討，我們發現元件的閘極漏電流主要是由HfO2的再結晶現象所貢獻的。我們也發現再經較高溫度(600~800oC)退火後，電容值會下降，這表示有一層低介電常數介面層的形成。我們可以使用TiN/Ti/HfO2閘極層來達到較小的等效氧化層厚度(EOT)，這層鈦金屬緩衝層能用來提高聚積電容值。為了要提高HfO2的再結晶溫度，我們使用MBE技術來沉積參雜20%Y2O3的HfO2，所參雜的Y2O3造成了活化溫度及介電常數的提升，然後能達到較佳的元件效能。另外，我們已經結合MBE及ALD(原子層沉積)技術來成長HfO2介電質。在成長ALD-HfO2之前，我們先用MBE沉積2 nm 的HfO2襯墊，這是我們首次使用這種方法來成長閘極介電層。如我們所預期，一個擁有此閘極氧化層的金氧半場效電晶體展現了極佳的成果，我們得到了ID = 240 mA/mm 以及 gm (transconductance)=120 mS/mm，這樣的結果大幅地改善了僅用ALD方式成長的元件特性，並與其他主要研究團隊所發表的結果相當。

In this MS thesis, we employed the molecular beam epitaxy (MBE) method to deposit amorphous HfO2 dielectrics (□ = 15) on silicon. We have demonstrated for the first time an atomically abrupt HfO2/Si interface free of SiO2 or silicate formation. In addition, TiN metal gate was deposited by reactive sputtering from a pure Ti target in Ar/N2 plasma. A two-steps annealing studies were carried out to improve the electrical performance of high-□ gate dielectric MOS capacitors. The interface trap density (Dit) were calculated by Terman method to be 1E12 eV-1cm-2. Furthermore, the thermal stability of TiN/MBE-HfO2 gate stack was studied. We found the gate leakage current could be attributed to the re-crystallization of the HfO2. We also found the capacitance was decreased after higher annealing temperature (600~800oC). It indicated the formation of low-κ interfacial layer. We could use a TiN/Ti/HfO2 gate stake to achieve smaller EOT. The Ti layer acted as a buffer to enhance the accumulation capacitance. In order to increase the re-crystallization temperature of the HfO2, we use MBE technique to deposit the HfO2 doped with 20% Y2O3. The Y2O3 doping leading to increased activation temperature and dielectric constant. Then a better device performance was achieved. Another approach on the dielectric using HfO2 had been carried out by combining MBE and ALD techniques. Prior to ALD-grown HfO2, a template of HfO2 (2nm) was deposited by MBE first. That’s the first time we use this method to grow the gate dielectric. As we expect, a MOSFET with such gate oxide displays excellent results. A ID of 240 mA/mm and gm of 120 mS/mm were attained, which were much better than that of simply ALD-grown case and comparable to the data reported by other major groups.

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