利用氧化銦覆蓋層以達到少層硒化銦電晶體的增強傳輸特性以及空氣中之穩定性

近幾年來，二維半導體材料如過渡金屬硫族化物 (TMD)、黑磷吸引了很多研究的目光。在本篇論文中，我們藉由研究半導體以及金屬介面的特性來了解硒化銦 (InSe) 的載子傳輸特性。由二維半導體製程的場效電晶體 (field-effect transistor) 中，金屬及半導體的介面和基板 (substrate) 是很重要的。因此，我們使用了六角形氮化硼 (h-BN) 作為基板以降低基板表面的粗糙度和減少介面的游離帶電雜質 (charged impurity)。為了防止光阻殘留在我們的硒化銦上，我們使用了一種無光阻殘留技術，利用聚酸甲酯 (PMMA) 當作薄膜蒸鍍罩 (stencil mask) 來製作多點電極。我們長了一層薄層的氧化銦 (Indium oxide)來改善接觸電阻 (contact resistance)。長了薄層氧化銦的場效電晶體有比沒有長薄層氧化銦的場效電晶體還低的48.7毫電子伏特的Schottky barrier height。在高閘極電壓的情況下，室溫中的金屬及半導體的接觸電阻 (contact resistance) 是5 kΩ μm。因為有好的接觸電阻，最高電流最高可以達到300 μA/μm並進入飽和區(saturation regime)。在2 K中，電流電壓特性曲線是呈現線性的，因此能夠宣稱我們擁有歐姆接觸 (ohmic contact)。在此種結構下，場效載子遷移率 (field-effect mobility)可以達到1400 cm2V-1s-1。低溫時，電流開關比 (on/off ratio)有107-108。最近我們發現硒化銦在一般大氣中是非常敏感的，我們藉由拉曼光普 (Raman spectroscopy)以及X射線光電子能譜學 (XPS)證實了硒化銦在空氣中會氧化。因此，這個薄層氧化銦能夠提供我們高品質的硒化銦氧化電晶體以應用在未來的電子元件。

關鍵字

硒化銦；六角形氮化硼；氧化銦；薄膜蒸鍍罩；歐姆接觸；最高電流

並列摘要

Two-dimensional (2D) semiconductors, e.g. black phosphorus and transition metal dichalgenides (TMDs), have attracted considerable interests recently. We investigate the electronic transport properties of Indium Selenide (InSe) by exploring the nature of the semiconductor-metallic contact interface. For 2D-material-based field-effect transistors (FETs), issues regarding substrate and contact are extremely important. We employed hexagonal boron nitride (h-BN) as the substrate of InSe FET to reduce surface roughness and suppress charged-impurity density at the interface. To avoid resist contamination in our FETs, we patterned polymethyl methacrylate (PMMA) as a stencil mask to realize residue-free four-probe measurement. A thin layer of Indium oxide is grown to improve the contact characteristics. We extract the Schottky barrier height (SBH) from activation energy in the thermionic emission regime. The SBH with the Indium oxide layer is reduced to 48.7 meV, compared with higher SBH without capping layer. Contact resistance is 5 kΩ μm with high gate voltage at room temperature. High drain current up to 300 μA/μm in the saturation regime at room temperature is achieved because of the low SBH and contact resistance. Electronic transport measurements show linear current voltage characteristics at high gate voltages at T=2 K, indicating ohmic contact with the Indium oxide layer. The field-effect mobility reaches 1400 cm2V-1s-1 and the on/off ratios is 107-108 at T=2 K. Lastly, we found that InSe is very sensitive to the ambient environment, and InSe is oxidized in ambient environment quickly based on Raman and XPS measurement. The measured transport properties suggest the high-quality of InSe with the Indium oxide interface as a conduction channel for the next-generation electronic devices.

並列關鍵字

InSe ； h-BN ； Indium oxide ； stencil mask ； ohmic contact ； high drain current

參考文獻

1 Michael Karbo, "PC architecture", (Denmark: ELI Aps, 2005).

2 I Present, "Cramming more components onto integrated circuits," Readings in computer architecture 56 (2000).

3 Robert H Dennard, Fritz H Gaensslen, V Leo Rideout, Ernest Bassous, and Andre R LeBlanc, "Design of ion-implanted MOSFET's with very small physical dimensions," IEEE Journal of Solid-State Circuits 9 (5), 256-268 (1974).

5 Jean-Pierre Colinge, "Multiple-gate soi mosfets," Solid-State Electronics 48 (6), 897-905 (2004).

6 Isabelle Ferain, Cynthia A Colinge, and Jean-Pierre Colinge, "Multigate transistors as the future of classical metal-oxide-semiconductor field-effect transistors," Nature 479 (7373), 310-316 (2011).

國際替代計量

利用氧化銦覆蓋層以達到少層硒化銦電晶體的增強傳輸特性以及空氣中之穩定性

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