由於金屬有機化學氣相沈積法成長氮化鎵的溫度為1050℃，氮化鎵材料在離子佈植後的快速熱退火處理中，材料表面的氮會因為高於成長溫度的快速熱退火處理而裂解，使得氮化鎵材料表面被破壞，影響材料的物理參數。本論文中在氮化鎵材料表面成長一層氮化鋁做為保護層，以期在快速熱退火處理過程中，防止氮化鎵材料表面氮的裂解。另外以霍爾量測比較氮化鎵有無成長保護層，在離子佈植活化後對於電性的改變。 在實驗中發現，成長氮化鋁保護層時，加熱氮化鎵基板，氮化鋁與氮化鎵的附著性較佳，經過熱退火處理後，氮化鋁保護層仍能覆蓋在氮化鎵材料上，達到保護的效果。 利用離子佈植的方式在p型氮化鎵材料中摻雜以矽離子，再以快速熱退火對摻雜的雜質活化，可使p型氮化鎵轉換成n型。進行霍爾量測，得到未加氮化鋁保護層的氮化鎵試片，載子濃度為-3.73x1013 cm-2，有氮化鋁保護層的試片，載子濃度提升為-1.02x1014 cm-2，活化率由3.7％提升至10％。 In this thesis, we deposited an AlN capping layer on GaN to prevent the decomposition of GaN surface. GaN films were grown by MOCVD at about 1050℃. In the thermal annealing process after ion implantation, the temperature higher than 1050℃ will cause the decomposition of GaN surface. By using the Hall measurement, we compared the electrical properties of GaN with AlN capping layer and without capping after thermal annealing. The 28Si+ implantation into p-type GaN followed by thermal annealing will makes the electrical properties transform from p-type to n-type. In the Hall measurement results, the GaN without capping has carrier concentration about 3.73x1013 cm-2, and the GaN with capping layer has carrier concentration about 1.02x1014 cm-2. Activation efficiency was improved from 3.7% to 10%. If the GaN substrates were heated during deposition process, then the adhesion of AlN films on GaN will be better to get improvement for protection on GaN surface.
