蔡豐羽臺灣大學:材料科學與工程學系暨研究所李昀潤Lee, Yun-JunYun-JunLee2010-07-142018-06-282010-07-142018-06-282008U0001-1310200815153400http://ntur.lib.ntu.edu.tw//handle/246246/189012本研究如何改善並最佳化原子層沉積(atomic layer deposition, ALD)於高分子基板上沉積之氧化鋁(Al2O3)無機層薄膜、做為封裝可撓曲電子元件之氣體阻障層。我們藉由測量試片對氦氣的氣體穿透率(Helium transmission rate, HeTR)作為封裝效能的指標。最佳化前驅物的暴露條件後，在基板表面以及前驅物徹底反應之下，讓ALD薄膜的成核趨於完整；挾著這樣的優勢，HeTR從原先的901.12降低到10.42 (cc/m2day)；而換算後已低於目前氧氣滲透率(OTR)測量儀器的極限:0.1 cc/m2day。外，在7-30奈米的厚度範圍內，本研究驗證了ALD薄膜阻氣效能隨薄膜沉積厚度而增加的相互關係。這是因為沉積厚度增加導致氣體穿透氣體阻障層的路徑變長所致。然本系統有很好的氣體阻障性，但氧化鋁薄膜由於和水氣強烈的反應傾向，儲存在空氣中顯得非常不穩定：50個小時後，HeTR上升了十倍。藉由在ALD製程中加入親水性較低的氧化鉿(HfO2)，氧化鋁/氧化鉿之複合無機結構有效地防止了水氣濃度入侵，儘可能地阻止了氧化鋁和水氣反應，在空氣中儲存了超過420個小時而沒有發現任何劣化。Aluminum oxide (Al2O3) thin films are applied to flexible polymer substrates as gas-permeation barriers by atomic layer deposition (ALD), and the barrier performance is evaluated by measuring the helium transmission rate (HeTR) of the barrier-coated PI substrates. The HeTR of the ALD films is reduced from 901.12 to 10.42 cc/m2 day by introducing precursor exposure steps in the initial stage of the ALD process; with the oxygen transmission rate (OTR) reduced to below the sensitivity, 0.1 cc/m2 day, of the available measurement apparatus. This improvement is attributed to enhanced nucleation of the ALD films as a result of the thorough surface-to-precursor interactions during the exposure steps. The barrier performance of the ALD films improves with the film thickness in the thickness range examined in this study, 7-30 nm. Despite having good barrier performance, the ALD Al2O3 films are highly unstable in air due to their strong tendency to hydrolyze in the presence of the ambient moisture, showing 10-fold increase in HeTR upon 50 hr of storage in air. This problem is resolved by laminating the Al2O3 films with ALD HfO2 films, which is performed in one ALD process. The laminated films maintain constant HeTR over 420 hr of storage in air. This improvement is attributed to the hydrophobicity of HfO2, which prevents moisture concentration from building up in the Al2O3 layers, thereby minimizing hydrolysis of the Al2O3 layers.Acknowledgement…………………………………...………………………..………….ibstract (Chinese)…………………………………...………………………..………...iibstract (English)...…………………………...………………………………………..iiiontents…………………………...……………………………………...……………..ivist of Tables and Figures.……...…………..….…...……………………….……...……vhapter 1 Introduction…………………………………………….........................1.1. Review of thin film gas barrier encapsulation…………………………………..1.1.1. The critical role of gas barrier for flexible electronic devices…………….1.1.2. The inadequacy of current thin film deposition technique….……………..4.1.3. The development of ALD gas barrier technology…………….……….......8.2. Objective statement…………………………………………………………….11hapter 2 Experimental details…………………………………………………..12.1. Materials………………………………………………………………………..12.2. Procedure, apparatus and characterization……………………………………12.2.1. Atomic layer deposition…………………………………………………12.2.2. Helium transmission rate measurement…………………………………15.2.3. Morphology observation…………………………………………………18hapter 3 Results and discussion………………………………………………...19.1 Effects of precursor exposure time and substrate pretreatement……………….20.2 Effects of film thickness………………………………………..........................27.3 Degradation of barriers in air…………………………………………………...30hapter 4 Conclusions and Future Works………………………………………34.1. Conclusions…………………………………………………………………….34.2. Future works……………………………………………………………………36eferences………………………………..…………………………………………….372821005 bytesapplication/pdfen-US氧化鉿氧化鋁原子層沉積無機薄膜氣體穿透率Al2O3HfO2ALDinorganic thin filmgas permeabilitythesishttp://ntur.lib.ntu.edu.tw/bitstream/246246/189012/1/ntu-97-R95527046-1.pdf