高介電感測材料於生醫感測之應用

High-k and sensitive materials for bio-sensor applications

李明玲(Ming-Ling Lee)

指導教授 ： 張國明

國立交通大學/電機學院/電子工程系所/博士(2018年)

摘要

近年來，高介電質材料相繼應用於ISFET 離子感測膜的製備上，相較於傳統二氧化矽 (SiO2) 感測膜，這些高介電材料具有較高的感測特性表現。本論文即探討應用一些新的高介電質材料的特性改善及應用。
首先探討氧化鋅(ZnO) : 氧化鋅屬透明導電氧化物 (TCO)，已被證實可應用於感測薄膜。過往研究指出ZnO可以分子束磊晶 (MBE) 方式沉積形成pH感測薄膜。本論文證實 (1)以射頻濺鍍方式於矽上方沉積ZnO，並經RTA退火製程，應用電解液-絕緣層-半導體結構 (EIS)，形成pH感測元件，提供與光電裝置集成的可行性應用。(2) 於射頻濺鍍時，摻雜鈦(Ti) 於ZnO感測薄膜中，可明顯改善薄膜表面特性，提升感測敏感度。此ZnO感測薄膜元件，經感測度、線性度、遲滯、時飄等特性量測，已驗證對生醫感測項目具敏感度，極具生醫感測元件應用潛力。
其次比較氧化鋅(ZnO) 與二氧化鈰(CeO2) : 本論文證實 (1)以射頻濺鍍方式於矽上方沉積CeO2，並經RTA退火製程，形成EIS結構之感測薄膜元件；其pH感測敏感度略優於ZnO感測薄膜。(2)改變RTA退火製程中的環境氣體為氮氣(N2)及氧氣(O2)；兩者相較，經氧氣退火製程的CeO2感測薄膜之pH感測敏感度較佳，因為在氧氣退火環境中，CeO2薄膜之氧空缺可被填補，而改善薄膜品質，進而提升生醫感測敏感度。
最後探討三氧化二釔(Y2O3)及二氧化鎳(NiO2) : (1) Y2O3具高介電常數、大導帶偏移、寬能帶隙和良好的介電熱穩定性，是於存儲器應用上極有潛力的材料之一。本論文證實以射頻共濺鍍Y2O3及Ti，形成摻雜Ti的Y2O3介電薄膜(Y2Ti2O5)，再經過RTA退火製程，其特性比原Y2O3電介質具有更好的介電強度，更低的漏電流和更大的崩潰電壓。(2) NiO2具高介電常數、寬能帶隙，過往文獻研已研究NiO2薄膜於電阻式隨機存取存儲器(RRAM)的應用。本論文證實於氧氣環境中濺鍍鎳(Ni)靶所沉積形成的NiO2薄膜，應用於高介電電荷捕捉層記憶體(MOHOS)，可取代傳統浮動閘極記憶體；可增加儲存的電荷容量，並利用快速熱退火技術及雜質摻雜技術，修補高介質材料與氧化層界面間的缺陷狀態、降低漏電流、提升資料保存能力、降低電荷損失。未來也將應用三氧化二釔(Y2O3)及二氧化鎳(NiO2)於EIS結構之感測薄膜元件。

關鍵字

高介電 ； 生醫感測 ； 氧化鋅

並列摘要

High-dielectric-constant (high-k) materials have recently been applied as ion sensing membrane. Compared with the traditional SiO2 sensing membrane, these high-dielectric materials have higher sensing performance. In this paper, the physical properties and sensing characteristics of some ne high-k materials were studied.
First, consider zinc oxide (ZnO): Zinc oxide which is a transparent conductive oxide (TCO) has been demonstrated to be applicable to sensing membrane. Previous studies have shown that ZnO can be deposited by molecular beam epitaxy (MBE) to form a pH sensing film. This paper proves (1) ZnO film was deposited on the silicon substrate by RF sputtering and subjected to RTA annealing process. Then apply electrolyte-insulator-semiconductor structure (EIS) to form the pH sensing device, which provided a feasible application of optoelectronic devices integration. (2) Incorporation of titanium (Ti) into ZnO film during RF sputtering can significantly improve the surface characteristics of the film and improve sensing sensitivity. The device with ZnO sensing membrane is sensitive for bio sensing items has been demonstrated by the sensing characteristics (pH sensitivity, hysteresis, drift, and selectivity) of these films.
Secondly, compare zinc oxide (ZnO) with Cerium dioxide (CeO2) : This paper proves (1) The pH sensitivity of CeO2 film which was deposited on the silicon substrate by RF sputtering and subjected to RTA annealing process is better than ZnO film. (2) To enhance the material quality and sensing performance, annealing treatment in N2 and O2 ambient has been incorporated. Results indicate that annealing treatment in O2 ambient exhibited a better sensitivity than N2 ambient, due to Oxygen in O2 ambient may cause stronger reflow and fill in the oxygen vacancy.
Finally, discuss the antimony trioxide (Y2O3) and nickel dioxide (NiO2) : (1) Y2O3 with high dielectric constant、large conduction band offset、wide energy band gap and good dielectric thermal stability, is one of the potential materials for memory applications. This paper proves that a Ti-doped Y2O3 (Y2Ti2O5) dielectric on polycrystalline silicon followed by rapid thermal annealing results in improved characteristics including a higher effective dielectric constant, lower electron trapping rate, and larger breakdown voltage. (2) NiO2 with high dielectric constant and wide energy bandgap. In this study, we proposed a metal-oxide-high-k-oxide-silicon (MOHOS) memory device using NiO2 film as the charge trapping layer traditional floating gate memory, and applied RTA to improve electrical and physical properties, including a larger C-V hysteresis window, better data retention, and smaller charge loss compared to other annealed samples. This type of MOHOS memory device shows great promise for future memory applications. In the future, we will also study EIS sensor with Y2O3 or NiO2 sensing membrane.

並列關鍵字

high-k ； bio-sensing ； ZnO ； EIS

參考文獻

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