以脈衝雷射鍍膜法成長PMN-PT薄膜及其性質量測
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2005
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摘 要
本研究是利用具有快速鍍膜及保持多元系統化學計量比的脈衝雷射鍍膜法( pulsed laser deposition，PLD )來進行0.67Pb(Mg1/3Nb2/3)O3-0.33PbTiO3 (PMN-PT)鐵電薄膜的生長。在判斷靶材與薄膜的相鑑定方面是以X-ray繞射儀來進行，薄膜厚度則是利用X-ray反射法來量測。由實驗的結果發現：在鍍膜溫度為600℃~700℃、氧壓為2x10-1 torr，可以在MgO(100)基板上成長出磊晶結構的薄膜；薄膜磊晶結構的品質則利用Φ- scan加以確認。
實驗中藉由成長不同時間的薄膜，發現薄膜在成長時間超過60分鐘後性質上的差異。薄膜的折射率及消光係數是利用橢圓偏光儀來量測，薄膜的表面粗糙度則是利用原子力顯微鏡掃描所獲得。由實驗亦發現：當薄膜成長時間超過60分鐘，開始出現(110)及焦綠石相等其它非磊晶的結構，這樣的現象亦可由折射率和消光係數的變化及表面粗糙度的大幅增加得到印證。最後，成長La0.5Sr0.5CoO3 (LSCO)為上下電極，順利的量測到薄膜的介電性及鐵電性(極化強度-電場)。
Abstract The growth of 0.67Pb(Mg1/3Nb2/3)O3-0.33PbTiO3 (PMN-PT) ferrooelectric thin films were prepared by pulsed laser deposition ( PLD ), which has the advantages of high depositing rate and maintaining the stoichiometrical ratio. The phase of target and thin films were identified with X-ray diffractometer, and the thickness of thin films was measured by x-ray reflectivity. Epitaxial 0.67PMN-0.33PT thin films on MgO(100) substrate were obtained by PLD at 600℃~700℃ and 2x10-1 torr (O2). The quality of epitaxial films was confirmed by Φ- scan. With different depositing time, we developed the differences of the properties by depositing thin films over 60 mintues. The refractive index and extinction coefficient of thin films were measured by spectroscopic ellipsometry, and the roughness of thin films were derived by atomic force microscopy. When the depositing time was over 60 minutes, thin films began to form other orientation of (110) and pyrochlore, and so on. It also proved by the variation of refractive index and extinction coefficient and the increase of roughness. Eventually, the dielectric and ferroelectric(P-E curve) were measured successfully by depositing the top and bottom electrode of LSCO.
Abstract The growth of 0.67Pb(Mg1/3Nb2/3)O3-0.33PbTiO3 (PMN-PT) ferrooelectric thin films were prepared by pulsed laser deposition ( PLD ), which has the advantages of high depositing rate and maintaining the stoichiometrical ratio. The phase of target and thin films were identified with X-ray diffractometer, and the thickness of thin films was measured by x-ray reflectivity. Epitaxial 0.67PMN-0.33PT thin films on MgO(100) substrate were obtained by PLD at 600℃~700℃ and 2x10-1 torr (O2). The quality of epitaxial films was confirmed by Φ- scan. With different depositing time, we developed the differences of the properties by depositing thin films over 60 mintues. The refractive index and extinction coefficient of thin films were measured by spectroscopic ellipsometry, and the roughness of thin films were derived by atomic force microscopy. When the depositing time was over 60 minutes, thin films began to form other orientation of (110) and pyrochlore, and so on. It also proved by the variation of refractive index and extinction coefficient and the increase of roughness. Eventually, the dielectric and ferroelectric(P-E curve) were measured successfully by depositing the top and bottom electrode of LSCO.
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脈衝雷射鍍膜, 鐵電材料, 鈣鈦礦結構, 磊晶薄膜