| 研究生: |
方啟鑫 Chi-Shin Fang |
|---|---|
| 論文名稱: |
高反射p型氮化鎵歐姆接觸之研究 Low-resistance ohmic contacts with high reflectivity on p-type GaN |
| 指導教授: |
綦振瀛
Jen-Inn Chyi |
| 口試委員: | |
| 學位類別: |
碩士 Master |
| 系所名稱: |
資訊電機學院 - 電機工程學系 Department of Electrical Engineering |
| 畢業學年度: | 92 |
| 語文別: | 中文 |
| 論文頁數: | 43 |
| 中文關鍵詞: | 高反射 、歐姆接觸 |
| 外文關鍵詞: | ohmic contact, reflectivity |
| 相關次數: | 點閱:7 下載:0 |
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本篇論文研究將針對在p型氮化鎵(p–type GaN)材料上進行高反射率歐姆接觸電極之製作,將紫外光波段上有高反射率的金屬材料,鋁(Al)、銀 (Ag)應用於歐姆接觸電極合金中,在與傳統之p型氮化鎵歐姆接觸電極合金 Ni/Au 相比較,新的金屬合金材料不但可以得到低阻值的歐姆接觸,並且可以提供良好的反射率,極適合作為覆晶發光二極體高紫光反射率接觸電極之應用。
在我們製作電極之前,需先將鎂原子在p型氮化鎵薄膜材料中活化,使其呈現高導電性,活化條件為750℃、30分鐘時具有最高濃度,其值約為1.49×1017 cm-3。而我們嘗試的金屬組合中,Ni/Ag/Au、Pd/Al/Ti/Au、Pd/Pt/Al/Ti/Au、Pd/Ni/Al/Ti/Au都有不錯的電性表現,其特徵阻值(specific contact resistance)分別為1.28×10-3(ohm-cm2)、6.69×10-3(ohm-cm2)、9.58×10-3(ohm-cm2)、1.01×10-2(ohm-cm2),而對應到370nm的反射率則分別為74%、75%、65%、70%。再針對反射率有上較佳表現的金屬組合探討其熱穩定性,其中Ni/Ag/Au、Pd/Al/Ti/Au、Pd/Pt/Al/Ti/Au有明顯變差的趨勢,因此我們結論為Pd/Ni/Al/Ti/Au為應用上較佳的金屬組合。
In this letter, we reported a low-resistance, thermally stable and high-reflectivity Pd(3 nm)/Ni(2 nm)/Al(150 nm)/Ti(20 nm)/Au(30 nm) Ohmic contact to p-type GaN: Mg (1.5×1017 cm-3 ). The specific contact resistance of the contact is as low as 1.23×10-2 ohm-cm2. After 48 hours annealing in a N2 ambient at 500℃, the specific contact resistance keeps below 1.5 ×10-2 ohm-cm2. The effect of Ni barrier layer of improvement of thermal stability in Pd(3 nm)/Ni(2 nm)/Al(150 nm)/Ti(20 nm)/Au(30 nm) is proposed and discussed in this work. Reflectivity of Pd(3 nm)/Ni(2 nm)/Al(150 nm)/Ti(20 nm)/Au(30 nm) Ohmic contact in the wavelength range of 350 to 400 nm is about 70%, which is expected to be beneficial for the fabrication of high efficiency nitride-based ultraviolet flip-chip light-emitting diodes.
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