臺灣博碩士論文加值系統

本論文以雙電子槍蒸鍍系統製備p-GaN的反射式歐姆電極AgSb(6 at%)、AgSb(2 at%)、Ag(150 nm)/Sb(4 nm)、AgMn(6 at%)、AgMn(4 at%)及Ag(150 nm)/Mn(2 nm)等六組試片，探討不同合金成分以及爐管退火(FA)與快速退火(RTA)兩種退火方式對於AgSb及AgMn反射式歐姆電極光電特性與熱穩定性的影響。探討內容包含反射式歐姆電極的光反射率、金屬薄膜片電阻與特徵接觸電阻，以及各性質之熱穩定性。並使用掃描式電子顯微鏡觀察試片表面樣貌，分析不同合金成分的特性差異及抑制退火後Ag薄膜凝聚的效果。我們發現Ag(150 nm)/Sb(4 nm)即可抑制Ag薄膜的高溫退火凝聚，AgSb合金退火後也不會有凝聚而破孔之現象。但Ag(150 nm)/Mn(2 nm)則無法抑制Ag膜凝縮，經過500 ℃爐管退火後Ag膜表面粗糙，凝聚成Ag的粒狀物，光反射率明顯下降。AgMn(4 at%)合金薄膜經500 ℃退火後表面未發現明顯破孔，可抑制Ag膜的凝縮。六組試片除AgSb(6 at%)外，經爐管退火或快速退火，且經400 ℃時效退火1小時後反射率變化不大，AgSb(6 at%)爐管退火後再經時效退火後反射率反而略微提升。六組試片的金屬薄膜片電阻與特徵接觸電阻數值皆具良好熱穩定性。綜合考量光反射率、金屬薄膜片電阻、特徵接觸電阻與熱穩定性，Ag(150 nm)/Sb(4 nm)有相當優異的表現。從歐傑電子能譜縱深分析可發現退火後Ag(150 nm)/Sb(4 nm)的 Sb溶進Ag薄膜形成AgSb合金，也就是說相當於1.5 at%即可抑制Ag膜的凝縮。Ag(150 nm)/Sb(4 nm)經大氣環境 500 ℃爐管退火10分鐘後，可以於460 nm藍光具94 %的光反射率，金屬薄膜片電阻約為0.1 Ω/□，特徵接觸電阻約為2.7 × 10-3 Ω-cm2且具良好熱穩定性，為優秀的歐姆電極。

In this study, all the samples AgSb(6 at%), AgSb(2 at%), Ag(150 nm)/Sb(4 nm), AgMn(6 at%), AgMn(4 at%), and Ag(150 nm)/Mn(2 nm) were deposited on the p-GaN by dual E-gun evaporation system. The samples were annealed at 500℃ by three different annealing conditions, furnace annealing(FA) in air ambient for 10 min, rapid thermal annealing(RTA) in O2 ambient for 1 min, and rapid thermal annealing(RTA) in air ambient for 1 min. Thermal stability test were performed by annealing at 400℃in air ambient for 60 min. Optoelectricproperties and thermal stability of p-GaN/AgSb and p-GaN/AgMn reflective ohmic contacts were investigated by SEM analysis, reflectance at 460 nm, sheet resistance of metal film , and specific contact resistance. The result show annealed Ag(150 nm)/Sb(4 nm) could suppress the agglomeration of Ag film. Auger depth profile showed Sb dissolved in Ag film for annealed Ag(150 nm)/Sb(4 nm). The specific contact resistance was 2.7 × 10-3 Ω-cm2 , reflectance was 94% at 460 nm, and sheet resistance of metal film was 0.1 Ω/□ for annealed Ag(150 nm)/Sb(4 nm) contact at 500℃ in air ambient for 10 min. The p-GaN/Sb(4 nm)/Ag(150 nm) reflective ohmic contacts showed good thermal stability.

摘要 I
致謝 II
目錄 IV
表格目錄 V
圖片目錄 VI
第一章 緒論
1-1 前言 1
1-2 基本理論 3
1-3 文獻回顧 8
1-4 研究動機與目的 12
第二章 實驗
2-1 試片設計 13
2-2 實驗方法 14
第三章 結果與討論
3-1 表面結構分析 18
3-2 退火對各試片光反射率及其熱穩定性的影響 19
3-3退火對金屬薄膜片電阻及其熱穩定性的影響 21
3-4 特徵接觸電阻量測結果與分析 22
第四章 結論 25
參考文獻 27
表格 表1 ~ 表5
圖片 圖1 ~ 圖59

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