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Title: | 金屬與鍺和鎳與鍺錫之接觸電性研究 Electrical characteristics of metal/n-Ge and Ni/n-GeSn contact |
Authors: | Hung-Yi Tsai 蔡弘毅 |
Advisor: | 鄭鴻祥(Hung-Hsiang Cheng) |
Keyword: | 鍺錫合金,費米能階釘札,歐姆接觸,比接觸電阻,蕭特基電位障,氧化鋁, GeSn alloy,Fermi level pinning,Ohmic contact,specific contact resistivity,Schottky barrier height,Al2O3, |
Publication Year : | 2015 |
Degree: | 碩士 |
Abstract: | 隨著科技的進展,以矽為基礎的金屬氧化物半導體場效電晶體已經達到它們的物理極限。在最近的發展中,鍺和鍺錫合金因為擁有比矽還高的載子遷移率,而被視為是金屬氧化物半導體場效電晶體之通道材料的可能候選。然而,在製程上許多關於鍺和鍺錫的挑戰依然需要克服。在這些問題中,最困難的是製造出一個低電阻的金屬與半導體接觸。
在本篇論文中,我們研究了金屬/N型鍺、鎳/N型鍺錫,以及鎳/本質鍺錫/N型鍺這三種結構的接觸電性。對於金屬/N型鍺的系統,由於介面能態以及鍺的原生氧化物的影響,費米能階釘札效應對於金屬/N型鍺的接面造成了一個嚴重的影響。這裡我們藉由熱退火的處理成功做出了金銻合金/N型鍺的歐姆接觸,其最小的比接觸電阻為0.622 (Ω∙cm^2)。我們也求出了金屬/N型鍺的其他電性參數,其中包括蕭特基電位障的值大約都是在0.5 (eV)。而為了能夠製作出一個穩定的金屬氧化物半導體的結構,我們放入不同厚度的氧化鋁在鎳/N型鍺之中。從電流-電壓和電容-電壓的特性中可以發現,對於鎳/氧化鋁/N型鍺的結構而言,6.7奈米和18.4奈米的氧化鋁表現出比較好的曲線及趨勢。 對於鎳/N型鍺錫的系統,N型鍺錫層的薄膜品質經由不同的量測方法來求得。我們成功做出了鎳/ N型鍺錫的歐姆接觸,並且得到比接觸電阻的值為4.361×10-3 (Ω∙cm^2)。我們也成長了一層氧化鋁來形成鎳/氧化鋁/N型鍺錫的結構,其中電性參數是從電流-電壓的量測中萃取。在最後一個部分,我們討論了不同厚度的本質鍺錫層對於鎳/本質鍺錫/N型鍺這種系統下的影響。從電流-電壓的量測中發現,隨著本質鍺錫層的厚度增加,鎳/本質鍺錫/N型鍺的順偏電流將會降低。 Following the advance of technology, silicon-based metal-oxide-semiconductor field-effect transistors (MOSFETs) are reaching their physical limits. In the recent development, Germanium (Ge) and Germanium-tin (GeSn) alloy have been considered as the possible candidates for the channel materials of MOSFET due to the higher carrier mobility compared to silicon (Si). Nevertheless, many challenges concerning Ge and GeSn still need to overcome. Among these issues, the most difficult is to fabricate a low resistance electrical contact between metal and semiconductor. In this thesis, we investigate the electrical characteristics of metal/n-Ge, Ni/n-GeSn, and Ni/i-GeSn/n-Ge. For the metal/n-Ge system, Fermi level pining has caused a severely influence on the metal/n-Ge interface due to the interface states and the Ge native oxide. Here we show that Ohmic contact of AuSb/n-Ge can be achieved by thermal annealing, and the minimum specific contact resistivity is 0.622 (Ω∙cm^2). The electrical parameters of metal/n-Ge system have been extracted, where the values of Schottky barrier height are in the same order of 0.5 (eV). In order to make a stable metal-oxide-semiconductor (MOS) structure, Al2O3 is placed between Ni/n-Ge with different thickness. From the current-voltage (I-V) and capacitance-voltage (C-V) characteristics, it shows a better trend for Ni/Al2O3/n-Ge with 6.7 and 18.4 nm Al2O3 layer. For the Ni/n-GeSn system, film quality of n-GeSn is measured by different characterization techniques. Ohmic contact to Ni/n-GeSn can be achieved, and the specific contact resistivity is 4.361×10-3 (Ω∙cm^2). We have grown an Al2O3 layer to form Ni/Al2O3/n-GeSn, where the electrical parameters have been extracted by the I-V measurement. In the last section, we discuss the influence of different i-GeSn thickness on the Ni/i-GeSn/n-Ge system. From the I-V measurement, forward current of Ni/i-GeSn/n-Ge is reduced when increasing the thickness of i-GeSn. |
URI: | http://tdr.lib.ntu.edu.tw/jspui/handle/123456789/53874 |
Fulltext Rights: | 有償授權 |
Appears in Collections: | 電子工程學研究所 |
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