利用原子層沉積二氧化鉿於二硫化鉬表面之研究

Abstract

本研究目的在於觀察利用原子層沉積（Atomic Layer Deposition）生長二氧化鉿（Hafnium Oxide, HfO2）介電層於過渡金屬硫族化合物（Transition Metal Dichcogenides, TMDs）-二硫化鉬（Molybdenum disulfide, MoS2）表面之介面關係。使用水氣和氧氣電漿作為不同氧來源來沉積二氧化鉿，並且運用氫氣、氧氣電漿處理的方式來活化二硫化鉬之表面，改善二氧化鉿之沉積品質。利用X光光電子能譜（X-ray Photoelectron Spectroscopy）來觀察二氧化鉿與二硫化鉬之介面，發現二硫化鉬因介電層的沉積，鉬原子3d與硫原子2p峰值向低結合能位移。利用光激螢光譜（Photoluminescence）與X光吸收光譜（X-ray Absorption Spectroscopy）來觀察二硫化鉬因二氧化鉿之電子與微結構變化，發現以水氣和氧氣電漿作為氧來源沉積二氧化鉿，皆會有p-doping的現象，且氣體電漿處理能使氧更容易與二硫化鉬鍵結，提供沉積二氧化鉿之氧來源。將利用此篇研究的結果改善二氧化鉿介電層之沉積品質，對於往後製作成二維電晶體元件之電性表現有所幫助。

This thesis investigated the growth and resultant surface properties of HfO2 dielectric layer on transition metal dichcogenides (TMDs), MoS2 with the use of atomic layer deposition (ALD). H2O and O2 plasma were used to modify the deposition of HfO2 as well as the activation of MoS2 surface. X-ray Photoelectron Spectroscopy was employed to explore the HfO2- MoS2 interface, and we obtained a spectral shift towards lower energy for Mo 3d-S 2p bonding upon the deposition of dielectric layer. Photoluminescence and X-ray Absorption Spectroscopy were utilized to the electronic structure and coordination. P-doping was obtained in grown HfO2. We found that gas-treament was facile to atomically bond oxygen and MoS2, thereby providing deposition site for HfO2. This thesis is aimed to shed lights to the growth mechanism and optimization of the growth of HfO2 dielectric TMDs which may benefit to the fabrication of 2D transistors.