二硫化鉬與二硫化鎢場效電晶體蕭特基能障分析

Analysis of Schottky Barrier on MoS2 and WS2 Field-Effect Transistors

朱昱誠(Yu-Cheng Chu)

指導教授 ： 邱博文

國立清華大學/電機資訊學院/電子工程研究所/碩士(2017年)

摘要

過渡金屬二硫族化物(Transition metal Dichalcogenides, TMDCs) 為二維層狀材料，可以單層狀態穩定存在於環境中，並且具有多樣的導電特性，如絕緣體、半導體甚至是超導等。其中半導體性TMDCs 如p 型WSe2 與n 型MoS2、WS2，其單層厚度僅0.7 nm，非常有潛力成為下個世代的通道材料。本論文先以化學氣相沉積高品質的MoS2 作為研究題材，並採用傳輸線模型與上閘極結構來分析MoS2元件金屬接觸特性與場效特性。在萃取蕭特基能障方面，將塊材MoS2、WS2轉移到經由HMDS改質後的基板上。並證實以Schottky Mott Rule 所推估的蕭特基能障不再適用，以及金屬與MoS2、WS2接觸後可能帶來的影響。量測後得知MoS2元件Ids−Vgs最大電流為14 μA/μm，遷移率為31.3 cm2/V．s，蕭特基能障為0.12 eV。在WS2元件方面Ids−Vgs最大電流為1.5 μA/μm，遷移率為8.9 cm2/V．s，蕭特基能障為0.16 eV。而在MoS2元件傳輸特性上觀察到MIT的現象，低溫時遷移率達到52.6 cm2/V．s。

關鍵字

二硫化鉬 ； 二硫化鎢

並列摘要

Transition-metal Dichalcogenides (TMDCs) are two-dimensional layered structure materials, which monolayer can exist in the ambient and have a variety of conductive properties. Such as insulator, semiconductor and even superconductor.
Among them, semiconducting TMDCs such as p-type WSe2 and n-type MoS2、WS2, the monolayer thickness only 0.7 nm which very promising to become the next generation channel material.
In the thesis, we first use chemical vapor deposition to grow a high quality MoS2 film on the sapphire. Then use the transmission line method and top gate structure to analyze MoS2 contact characteristics and field-effect property.
In terms of extracting Schottky barrier high, the bulk MoS2、WS2 was transferred to the substrate which modified by HMDS.
And confirmed that Schottky barrier high estimated by the Schottky Mott Rule is no longer applicable, and the metal contact MoS2、WS2 which possible to impact the material.
After measuring, MoS2 Ids−Vgs maximum current is 14μA/μm, mobility is 31.3 cm2/V．s, and Schottky barrier high is 0.12 eV. On the WS2, the Ids−Vgs maximum current is 1.5 μA/μm, mobility is 8.9 cm2/V．s, and Schottky barrier high is 0.16 eV. We also observe MIT phenomenon at the MoS2 transmission characteristics, the mobility at low temperature up to 52.6 cm2/V．s.

並列關鍵字

MoS2 ； WS2

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