β-Ga₂O₃ 作為第四代超寬能隙半導體的核心材料,憑藉 4.9 eV 的超寬能隙、約 8 MV/cm 的理論崩潰電場與本質日盲紫外響應特性,在高壓功率元件與深紫外光電感測等領域具有不可取代的應用價值。然而,β-Ga₂O₃ 的 p 型摻雜長期面臨三大瓶頸:受體摻雜的施體補償效應顯著、受體能階偏深導致室溫游離困難、佈植晶格損傷的可控性不足,致使活化效率低落,成為限制其 pn 接面元件研發與產業化的核心障礙。離子佈植具備摻雜劑量、深度與區域精準可控的優勢,磁控濺鍍則可實現大面積、高均勻性薄膜的規模化製備;惟過往受體佈植研究幾乎集中於單晶基板,針對濺鍍多晶薄膜的系統性研究仍屬空白。本文結合二者,為濺鍍 β-Ga₂O₃ 薄膜的 p 型化建立完整的製程與機制基礎。

本文以 350 nm 濺鍍純 β 相薄膜為研究基底,選取 Mg²⁺ 與 Cu²⁺ 兩種代表性受體離子,採單一變數法系統調控佈植劑量、佈植能量、退火溫度與退火時間四大核心製程參數,結合 XRD、SEM、XPS 與霍爾效應量測,量化分析製程參數對晶體結構、晶格缺陷、表面形貌、受體晶格佔位與電學特性的影響規律,揭示受體活化的微觀機制,並釐清薄膜由 n 型轉變為 p 型的臨界條件與核心調控因素。

研究結果表明:離子佈植存在明確的損傷閾值,劑量 1×10¹⁴ cm⁻² 與能量 100 keV 構成低損傷摻雜製程視窗,於此視窗內晶格損傷可逆、離子峰值深度(180 nm)落於薄膜中央;退火是實現受體活化與電性轉變的必要步驟,氮氣氣氛 900 ℃ 持溫 60 min 為最佳退火組合,可使晶格完全回復至空白薄膜水準,Cu²⁺ 晶格佔位率達 95.7%、受體活化效率達 32%,並實現穩定不回退的 p 型導電(電洞濃度 4.8×10¹⁵ cm⁻³、遷移率 7.4 cm²/(V·s));Mg²⁺ 之佔位率與活化效率分別為 91.2% 與 28%。比較研究證實,Cu²⁺ 憑藉相對較淺的受體能階與較佳的化學鍵結相容性,綜合摻雜性能優於 Mg²⁺,為濺鍍薄膜 p 型摻雜的較佳受體離子;由兩種離子的實測值並可歸納出受體能階深度每降低 0.01 eV、活化效率約提升 0.57% 的經驗規律。本文進一步量化了缺陷對活化的調控作用,界定穩定 p 型導電的缺陷容忍邊界介於差排面密度 0.9 至 1.5×10¹² cm⁻² 之間,並建構「晶格佔位-缺陷修復-載子傳輸」耦合的三階段活化機制模型,闡明受體離子替位至 Ga 晶格位形成電學有效受體、經退火活化後釋放電洞,是電性轉變的核心;而高濃度晶格缺陷引發的載子補償效應,則是抑制活化效率的關鍵誘因。

本研究確立了濺鍍 β-Ga₂O₃ 薄膜 p 型摻雜的完整製程體系,量化了製程參數與材料性能的關聯規律,並將摻雜活化理論延伸至濺鍍多晶體系,為 β-Ga₂O₃ p 型製程的工業化最佳化與高性能光電、功率元件的研發提供了實驗依據與技術支持,對推動超寬能隙半導體的發展具有理論價值與工程意義。

β-Ga₂O₃ is a fourth-generation ultra-wide-bandgap semiconductor, yet the absence of reliable p-type conductivity remains the decisive obstacle to its bipolar devices. This thesis establishes a complete p-type doping process for sputtered polycrystalline β-Ga₂O₃ thin films, a technologically scalable platform that previous implantation studies, which focused on single crystals, have left unexplored. Mg²⁺ and Cu²⁺ acceptors were implanted into 350-nm pure-β-phase films and activated by nitrogen annealing, with dose, energy, temperature, and time varied one at a time and characterized by XRD, SEM, XPS, and Hall measurements. A low-damage process window of 1×10¹⁴ cm⁻² and 100 keV was identified, within which implantation damage is fully recoverable. Annealing at 900 °C for 60 minutes restores the lattice to the pristine level and drives acceptors onto gallium sites, achieving a stable n-to-p conversion with a Cu²⁺ site-occupancy ratio of 95.7%, an activation efficiency of 32%, a hole concentration of 4.8×10¹⁵ cm⁻³, and a mobility of 7.4 cm²/(V·s). Copper outperforms magnesium owing to its shallower acceptor level and superior bonding compatibility. A three-stage activation model coupling lattice-site occupation, defect recovery, and carrier transport is constructed, and a defect-tolerance boundary for stable p-type conduction is quantified, providing design rules for industrial p-type doping of β-Ga₂O₃.

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