藉由大氣電漿在不同前驅物下沉積二氧化矽薄膜其電性與表面型態之研究

Abstract

半導體工業廣泛地將二氧化矽應用在元件上，包括閘極介電層與元件之間的阻隔層，但是對於光電產業而言，玻璃基板與塑膠基板皆無法承受氧化爐管的高溫製程，必須以低溫製程的PECVD 來沉積二氧化矽，對於基板面積日益增大的光電面板，如果設計更大體積的真空腔體與泵浦系統將會提高設備成本，因此利用大氣電漿沉積二氧化矽薄膜，除了擁有低溫製程的優點之外，不需要額外的真空腔體與泵浦系統，除了可應用在大面積的基板，且大幅降低了設備成本。本實驗藉由大氣電漿分別在不同前驅物HMDSN 與HMDSO 下沉積二氧化矽薄膜，並且改變機台參數包括Ar 載氣流量、基板加熱溫度、不同電漿工作氣體等，來探討其電性與表面觀測的結果，當我們分別降低Ar 載氣流量或升高基板溫度至150°C 時，由前驅物HMDSN 沉積的二氧化矽薄膜其漏電流在0.5 MV/cm 下，可以達到10-7 (A/cm2) 水準，可應用在OTFTs的閘極介電層，尤其薄膜接觸角達到63°呈現疏水性，尚可以增加有機主動層的附著性。另外，當我們分別增加Ar 流量、降低基板溫度、提升電漿氣體的氧氣比率，皆可增加表面粗糙度，可當作太陽能電池的抗反射層，並且省去許多抗反射層的製程步驟。

The semiconductor industry widely use silicon dioxide on devices, including gate insulator and field oxide, but the glass and plastic substrate of photoelectric undertaking can’t endure high temperature such as thermal oxidation. We must use low-temperature process of PECVD to deposit silicon dioxide. With the area of display increase day by day, we have to design larger vacuum chamber and associated pumping system but the cost of equipment will increase. The atmospheric-pressure plasma system has the advantage of low cost, high processing speed, and simple system with no vacuum equipment. In this experiment, we deposited silicon dioxide thin films by atmosphere-pressure plasma jet with different precursors including HMDSN and HMDSO. We vary the parameters of Ar flow rate, substrate temperature, and main gas in order to investigate the electric characterization and surface roughness. When we decrease Ar flow rate and increase substrate temperature to 150 °C respectively. The leakage current of silicon dioxide thin films deposited by atmosphere-pressure plasma jet with HMDSN can attempt to 10-7 (A/cm2) at 0.5 MV/cm, which may be applied for gate insulators of OTFTs. And the film is hydrophobic with 63 ° contact angle, by which can increase the adhesion of organic active layer. Besides, as we increase Ar flow rate, decrease substrate temperature, and increase the proportion of oxygen respectively. All above can increase surface roughness which may be applied for solar cell as anti-reflection layer, which could reduce multi-processes.