脈衝雷射沉積二硫化鉬場效電晶體之研究

本文使用脈衝雷射沉積薄膜(PLD)和射頻電漿輔助式雷射沉積薄膜(RF-PLD)，選用二硫化鉬靶材(MoS2)來製備薄膜應用於二硫化鉬薄膜電晶體上，並且觀察其薄膜特性及電性研究，首先我們購買約300 nm厚的二氧化矽(SiO2)絕緣層摻雜在矽基板上，並且使用Nd：YAGLaser 波長532 nm依照不同環境條件聚焦後轟擊二硫化鉬靶材，產生電漿並且在二氧化矽上面形成二硫化鉬薄膜，依照不同條件的生長方式會有不同情況的薄膜，我們使用SEM觀察二硫化鉬薄膜的表面情況以及剖面厚度、XRD觀察二硫化鉬結晶情形、以及用XPS確認二硫化鉬的元素比例，最後放上光罩(Mask)，使用熱蒸鍍機蒸鍍約50 nm厚的金當作我們電晶體的電極，而半導體層的通道長度為1.5 mm、通道寬度為0.1 mm，而閘極則是原件底部的矽基板，其中我們在許多不同的薄膜條件下，超過10分鐘的薄膜由於經歷過大電阻太高無法使電流輕易流過，少於3分鐘的薄膜相當不均勻甚至只有晶粒產生，因此我們發現在5分鐘並導入RF 31 W後成功的測量出電晶體的輸出飽和曲線圖，利用公式算出載子遷移率為0.003 cm2/V s，隨後我們將3分鐘的條件一樣導入RF 31 W後，成功的提升了電性狀態，並且利用公式算出載子遷移率為0.017cm2/V s、臨界電壓為-4.64 V、電流開關比On/off ratio＞102。關鍵詞:脈衝雷射、二硫化鉬、薄膜電晶體

關鍵字

脈衝雷射；二硫化鉬；薄膜電晶體

並列摘要

We use Pulsed Laser Deposition Thin Film (PLD) and Radio Frequency Plasma Laser Deposition(RF-PLD) to form MoS2 thin film transistor by MoS2target ,observed the characteristic of thin film and electrically . First we buy insulator SiO2 about 300 nm ,which doping in Si substrate ,and use Nd：YAG Laser with wavelength 532nm to bump MoS2targetin any case ,then it will generate plasma to form different MoS2 thin film on SiO2in different growth condition. We observe the surface condition of MoS2 thin film by SEM ,crystal case by XRD and the percentage of element by XPS. Finally ,put on the mask and use Thermal Coater Deposition to form Au as electrode on MOSFET about 50nm ,which channel length is 1.5 mm channel width is 0.1 mm ,and the gate is Si substrate .In different condition ,resistance too high to enable the current to flow through easily over ten minutes ,the film is quite uneven and even produce only grains less than three minutes .Therefore ,we can measure the output saturation curve on MOSFET with RF 31 W in five minutes which mobility is 0.003 cm2/V s. Besides, with RF 31 W but in three minutes, and upgrade the electrical characteristic which mobility can achieve 0.017cm2/V s, Vth is -4.64 V and on/off ratio ＞102 .