- 學位論文
以氮氣輔助熱退火製程提升摻鎵氧化鋅薄膜特性之研究
Study on improving the properties of Gallium-doped ZnO films by nitrogen-assisted thermal annealing process
摘要
本研究首先使用低成本簡易濺鍍製程方式沉積摻鎵氧化鋅薄膜(GZO)，並再藉由快速熱退火於通入氮氣氛輔助下提升其光電特性。製程首先優化沉積GZO薄膜，主要以間歇性製程進行，其主要將一次性沉積薄膜分成數段式成長，其中主要兩種參數分別為間歇次數(Intermittent Number, IN)以及間歇時間(Intermittent Time, IT)，再以上述優化後之IN及IT進行快速熱退火之後製程處理，於取得最佳退火溫度以及時間後，再進行通入適量氮氣輔助製程，由於在優化之退火溫度及時間下通入適量的氮氣輔助下，可藉由氮原子強化薄膜鍵結，及氧空缺適量補足下進而再次提升光電特性。本研究使用射頻磁控濺鍍機成長厚度80nm GZO薄膜，首先調變不同間歇次數0~3次並固定間歇時間10分鐘，找出最佳間歇次數之後調變間歇時間5~12.5分鐘。再依據最佳參數IN及IT進行快速熱退火後製程處理，首先調變退火溫度為650~850°C，持溫時間固定10分鐘，找出最佳退火溫度之後進行調變退火時間5~15分鐘。最後固定以上研究之最佳參數再調變通入氮氣流量5~15sccm，藉以輔助優化薄膜結構提升光電特性。研究過程中亦使用霍爾載子量測系統(Hall-Effect Measurement)、掃描式電子顯微鏡(SEM)、X光繞射儀(XRD)、UV-VIS光譜儀等設備進行薄膜特性分析。經研究後發現當IN=1、IT=7.5有最佳之光電特性，再處以退火溫度750°C、退火時間5分鐘，並於通入氮氣流量10sccm，確實有效輔助熱處理機制，使GZO薄膜最後電阻率由6.11×10-1 Ω-cm下降至8.75×10-3 Ω-cm，且最佳光電效益值(FOM)由6.34×10-6 Ω-1提升至1.60×10-4 Ω-1。
並列摘要
In this study, a low-cost simple process method as sputtering was used to deposit Gallium-doped zinc oxide film and passed through rapid thermal annealing below the Nitrogen assists to improve photoelectric properties. The simple method as intermittent process is intended to divide the one-time deposited film into segmented growth. So it mainly contains two parameters as Intermittent Number (IN) and Intermittent Time (IT). In this study, an RF magnetron sputtering was used to grow 80nm thick GZO film. At first, the IN number is adjusted as 0~3 and fix the IT for 10 minutes. After finding the best IN, the IT is adjusted as 5~12.5 minutes. The following rapid thermal annealing process is performed according to the optimal parameters IN and IT, them the annealing temperature is adjusted as 650~850°C, and the time is fixed as 10 minutes. After finding the optimal annealing temperature, the annealing time is adjusted as 5-15 minutes. Finally, the optimal annealing temperature and time is fixed,them the nitrogen flow rate as 5~15sccm had been done to optimize the film structure and improve the photoelectric characteristics. The change rate of resistivity is measured by Hall characteristic measurement system,the structural property of the thin film is analyzed by X-ray diffraction (XRD) . The surface morphology is observed by using field emission scanning electron microscope (FE-SEM). The light transmittance will be measured with an UV spectrometer. As the results, when the process is IN=1,IT=7.5 and annealing temperature as 750°C for 5 minutes,and the Nitrogen flow is 10 sccm,which have lowest resistivity 8.75× 10-3 Ω-cm and the Figure Of Merit (FOM) is 1.60×10-4 Ω-1. In this study the Nitrogen-assisted had been verified to improve the optical and electrical properties of GZO film.