| 摘要: | 通訊技術進入5G時代後，逐步走向高頻率、高功率、低能源損耗、小體積的方向前進，氮化鎵(Gallium nitride，GaN)作為第三代半導體材料，具有寬能隙與高載子遷移率特性適合應用於高功率與高頻應用，因此氮化鎵被視為能夠解決5G技術需求至關重要的材料。
目前磊晶單晶氮化鎵薄膜以有機金屬化學氣相沉積( Metal-organic Chemical Vapor Deposition ，MOCVD)高溫製程為主，具有高成本的問題，因此本論文在氮化鋁為緩衝層之藍寶石基板上，以低溫製程且具有大面積製造特性的磁控濺鍍系統下濺鍍單晶氮化鎵薄膜，並探討溫度、氮氣比例、電壓、充放能時間之生長結構，由X射線繞射儀(X-ray Diffractometer，XRD)分析中得到半高寬最低的垂直生長參數，原子力顯微鏡(Atomic Force Microscopy ，AFM)分析中得到粗糙度最低的橫向生長參數，並透過掃描式電子顯微鏡(Scanning Electron Microscopy，SEM)分析膜側面與表面結構、拉曼分析儀(Raman Spectrophotometry)分析E2與A1峰值與穿透式電子顯微鏡(Transmission Electron microscopy ，TEM)分析結晶品質。
最後先垂直生長佳之單晶氮化鎵薄膜，再將橫向生長佳之單晶氮化鎵薄膜磊晶在其上，成長不同厚度的橫向磊晶薄膜，並藉由上述儀器觀察到半高寬由原本的c軸[0002]方向0.210 degree改善到0.208 degree，保持了疊加前的結晶性，表面粗糙度由8.25nm下降到5.65nm，大幅度的提升了表面平整性，且因疊層的影響，晶格間距差從原本的0.0015nm，減少到0.0009nm。因此我們成功得到結晶性、平整度與應力較佳的氮化鎵薄膜。
;The communication technology has entered the 5G era, the development of science and technology has gradually been moved towards high frequency, high power, low power consumption, and small volume. As a novel third-generation semiconductor material, gallium nitride (GaN) includes the properties of wide energy bandgap, high electron mobility, high temperature resistance, high voltage resistance. Therefore, GaN plays an important role to achieve one of the solutions for 5G technology equipment.
The most popular process to grow the epitaxial single crystal gallium nitride film is using the metal organic chemical vapor deposition (MOCVD). The high temperature MOCVD process has the high-cost disadvantage. In this paper a magnetron sputtering technique with low process temperature and large-scale deposition capacity has been applied on the sapphire with an aluminum nitride buffer layer. The process temperature, working-gas ratio, voltage, and charge/ discharge time have been analyzed. The vertical growth parameters with the lowest half-maximum-full-width (HMFW) were obtained by X-ray diffractometer (XRD), and the lateral growth parameters with the lowest surface roughness were obtained by the atomic force microscopy (AFM). The side and surface structures of the film were analyzed by the scanning electron microscopy (SEM). The Raman scattering spectrophotometry was used to analyze Raman spectra of E2 and A1 peaks and transmission electron microscopy (TEM) was used to analyze crystal quality.
The best vertical growth epitaxial gallium nitride film with the c-axis [0002] FWHM 0.243 degrees was deposited on the substrate, then the different thickness of the lateral growth epitaxial gallium nitride film was grown on the vertical growth film. Observed by the above instruments, the c-axis [0002] FWHM was reduced from 0.210 degree to 0.208 degree, and the surface roughness is reduced from 8.25 nm to 5.65 nm. The lattice spacing difference was also reduced from 0.0015 nm to 0.0009 nm. Finally, the high crystallinity, good surface flatness and low stress epitaxial gallium nitride film has been achieved successfully. |
