長在凹型圖案化氧化錫基板氮化鎵發光二極體與鈦摻雜二 氧化錫之感測薄膜

Abstract

論文中分為兩部分：高功率 GaN 發光二極體(LED)與感測器。 其中第一部份是高功率 GaN 發光二極體，有高亮度、高效率、尺 寸小、壽命長等優點，已取代傳統燈源成為下一世代固態照明的 燈源。實驗第一部分主要是利用濕式蝕刻藍寶石基板去製作凹型 圖型化藍寶石基板後，再去磊晶氮化鎵並做分析。發現晶體的品 質與光的強度會隨圖型的間距減少而增加。但當間距小到 0.41 微 米（S0.41-GaN）時，晶體品質變差，不過光的強度仍是提升。這 是因為光取出率增加的原因。 第二部份是使用鈦摻雜二氧化錫沉積於矽晶片基板，做為電 解質-絕緣體-半導體結構(EIS)生醫感測元件之感測膜。我們主要 探討在通氧環境下使用不同熱退火溫度從 500 到 800°C 來改善感 測薄膜的特性。由此可以看出在退火通氧環境 700°C 下可獲致最 佳的感測特性，具有較高的氫離子感測度、遲滯、時飄的特性。 同時我們進而分析 XRD、XPS、和 AFM 等相關的物性與材料分析， 皆可得到與感測特性相對應之結果，亦即在退火通氧環境 700°C 下皆可得到較佳的鈦摻雜二氧化錫薄膜結構與相關物性。此乃因 鈦摻雜能增強薄膜鍵結，減少薄膜表面之損傷鍵結，同時改善薄 膜於不同溫度下之可靠度。此外，我們也將以上所研究之感測薄 膜，使用於鈉、鉀離子溶液下比較，可以得知所研究之感測膜在 氫離子比起鈉、鉀離子皆有較高的感測特性。

The thesis includes two themes: First part is a detailed study of Crystal quality and light output power of GaN LED on micro-concave patterned sapphire substrate. The second part is a comparative study of SnO2 and SnTiO2 sensing membrane applied for EIS based biosensing applications. Brief description of the study is as follows. First Theme: The crystal quality and light output power of GaNbased LEDs grown on micro-concave patterned sapphire substrate (CPSS) were investigated. It was found that the crystal quality of GaN-based LEDs grown on CPSS improved with the decrease of the pattern space (percentage of C-plane). However, when the pattern space decreased to 0.41 μm (S0.41-GaN), the GaN crystallinity dropped. On the other hand, the light output power of GaN-based LEDs was increased with the pattern space due to the change of the light extraction efficiency. Second Theme: We investigated the effect of rapid thermal annealing (RTA) on the sensing and structural characteristics of Tidoped SnO2 based electrolyte-insulator-semiconductor (EIS) pH sensors. Ti-doped Tin oxide (SnO2) EIS sensor with 700 °C post deposition annealing exhibited the best sensing characteristics in terms of sensitivity, linearity, hysteresis and drift rate. This is because Ti incorporation can improve the thin-film stoichiometry by reducing dangling bonds on the dielectric surface and improve the temperature stability. We further studied the structural, compositional, and morphological characteristics of the deposited thin-film. RTA treatment increases the sensitivity and linearity by creating larger grain size with larger grain boundaries and higher number of surface sites. Sodium (Na+ ) and potassium (K+ ) sensing performance also measured using fabricated EIS sensors.