本研究針對以高功率脈衝磁控濺鍍（High-Power Impulse Magnetron Sputtering, HiPIMS）製備之非晶態氮化鎵（amorphous GaN, a-GaN）薄膜進行系統性製程參數優化，並應用於1550 nm光通訊波段之光波導結構中，探討其光學傳輸特性。藉由調變濺鍍氣體比例、放能/蓄能時間（on/off time）、功率、基板偏壓與基板溫度等關鍵製程條件，分析對薄膜折射率、消光係數與表面粗糙度之影響，並找出可有效抑制吸收損耗與提升波導性能之最佳條件。實驗結果顯示，當基板溫度設定為150°C時可獲得最佳薄膜特性，其折射率約為2.25、消光係數低至0.00012，表面粗糙度維持於0.615 nm範圍內。進一步以Rsoft與Lumerical進行模擬分析，驗證材料光學常數與波導損耗之關聯性；並製作實際波導元件進行頻譜量測，於最佳製程條件下可實現最低傳輸損耗為1.09 dB/cm，較高吸收條件下（k=0.00490）所對應之2.37 dB/cm損耗有所降低。結果證實材料的消光係數為影響波導損耗的關鍵因素，亦顯示HiPIMS技術具備在低溫下製備高品質、低損耗a-GaN薄膜之能力，可望應用於未來CMOS相容之光電積體元件開發。;This study investigates the fabrication and optimization of amorphous gallium nitride (a-GaN) thin films deposited by High-Power Impulse Magnetron Sputtering (HiPIMS) for low-loss optical waveguides operating at the 1550nm optical communication wavelength. The influence of key deposition parameters—including gas flow ratio, pulse on/off time, sputtering power, substrate bias, and substrate temperature—on the refractive index, extinction coefficient, and surface roughness of the films was systematically investigated. Optimal optical performance was achieved at a substrate temperature of 150 °C, resulting in an extinction coefficient as low as 0.00012, a refractive index of approximately 2.25, and a surface roughness of 0.615 nm. Waveguide loss simulations using Rsoft and Lumerical confirmed a strong correlation between the extinction coefficient and propagation loss. Experimental waveguide structures were fabricated under optimal conditions exhibited a minimum propagation loss of 1.09 dB/cm compared to 2.37 dB/cm for films with higher absorption conditions (k=0.00490). These results identify the extinction coefficient as the dominant factor affecting waveguide loss and demonstrate the feasibility of using HiPIMS to produce low-loss a-GaN films at low temperatures, enabling CMOS-compatible photonic integration using amorphous GaN materials.
