氮化鎵高電子遷移率電晶體之銅金屬化導線製程

Abstract

這篇論文在研究，將 鈦/氮化鎢/鈦/銅 和 鈦/鉑/鈦/銅 當薄金屬結構使用在銅金屬化導線製程應用在氮化鎵高電子遷移率電晶體之可行性，以及藉由歐傑電子能譜儀來分析薄金屬結構的熱穩定性。 將氮化鎢和鉑作為擴散阻擋層、鈦作為粘附層應用在銅金屬化導線的氮化鎵高電子遷移率電晶體已成功被製造出來，且將其與金導線的氮化鎵高電子遷移率電晶體相比較，兩者展現出來的電流特性可相媲美。 並藉由歐傑電子能譜儀來分析 金/鈦/氮化鎢/鈦/銅 和 金/鈦/鉑/鈦/銅這兩種多層結構，來判斷銅和金兩種金屬是否穿過擴散層而開始互相擴散。由結果指出鈦/氮化鎢/鈦/銅 之薄金屬結構的熱穩定性可達 400℃，而鈦/鉑/鈦/銅之薄金屬結構的熱穩定性可達 350℃ 這些結果顯示銅金屬化空氣橋製程可以應用在氮化鎵高電子遷移率電晶體上。

In this thesis, the feasibility of using Ti/WNx/Ti/Cu and Ti/Pt/Ti/Cu thin metal structures for Cu-metallized interconnects on GaN high electron electron mobility transistors (HEMTs) is studied and the thermal stability of the thin metal structure is investigated. The use of WNx and Pt as the diffusion barriers and Ti as the adhesion layer for the use of Cu-metallized interconnects on GaN HEMT is successful implemented. In comparison with the Au-metallized devices, the Cu-metallized devices exhibited comparable DC characteristics. In addition, AES depth profiles was used to study the copper and gold began to is inter diffusion using WNx and Pt diffusion barrier layers in order to test the thermal stability of Au/Ti/WNx/Ti/Cu and Au/Ti/Pt/Ti/Cu multilayer structures. The results indicate that the Ti/WNx/Ti/Cu thin metal structure was thermally stable up to 400℃and the Ti/Pt/Ti/Cu thin metal structure was thermally stable up to 350℃. These results show that the Cu-metallized airbridges using the proposed metal scheme can be used as the interconnects for GaN HEMTs.