基于柔性显示器件的氧化铝介电层室温制备
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摘要
在室温环境下采用射频磁控溅射方法制备了氧化铝(A_l2O_3)薄膜,通过调节溅射气压实现了对薄膜特性的优化控制。当溅射功率为120 W、Ar气压强为0.13Pa时,制备的A_l2O_3薄膜具有最好的厚度均匀性,薄膜中Al和O的原子比为1∶1.67,密度为3.21g/cm~3,粗糙度为0.62nm。这种平滑、致密的薄膜结构能够有效地减少缺陷的形成,获得高击穿电压、高相对介电常数和低漏电等性能。利用优化后的A_l2O_3薄膜作为栅极绝缘层,在聚酰亚胺树脂(PI)基板上室温制备了柔性非晶态铟镓锌氧化物-薄膜晶体管(α-IGZO-TFT),其迁移率为2.19cm2/(V·s),开关比达到105,亚阈值摆幅为0.366V/decade,阈值电压为3.01V。
Aluminum oxide(A_l2O_3)thin films are prepared by radio frequency magnetron sputtering at room temperature,and the optimal control of the properties of these films is realized by adjusting the sputtering pressure.The prepared films with the best thickness uniformity are obtained under the sputtering power of 120 W and Ar pressure of 0.13 Pa,whose ratio of aluminum atoms to oxygen atoms is 1∶1.67,density is 3.21g/cm3,and surface roughness is 0.62 nm.This smooth and compact A_l2O_3 thin film can significantly reduce the defects,and it also possesses the characteristics of high breakdown voltage,high relative dielectric constant and low leakage current.The flexibleα-IGZO-TFTs are prepared on a polyimide(PI)substrate at room temperature by utilizing the optimized A_l2O_3 films as the gate insulation layer,and exhibit electrical performance with a mobility of 2.19cm2/(V·s),an on/off current ratio of 105,a sub-threshold swing of 0.366V/decade,and a threshold voltage of 3.01 V.
Aluminum oxide(A_l2O_3)thin films are prepared by radio frequency magnetron sputtering at room temperature,and the optimal control of the properties of these films is realized by adjusting the sputtering pressure.The prepared films with the best thickness uniformity are obtained under the sputtering power of 120 W and Ar pressure of 0.13 Pa,whose ratio of aluminum atoms to oxygen atoms is 1∶1.67,density is 3.21g/cm3,and surface roughness is 0.62 nm.This smooth and compact A_l2O_3 thin film can significantly reduce the defects,and it also possesses the characteristics of high breakdown voltage,high relative dielectric constant and low leakage current.The flexibleα-IGZO-TFTs are prepared on a polyimide(PI)substrate at room temperature by utilizing the optimized A_l2O_3 films as the gate insulation layer,and exhibit electrical performance with a mobility of 2.19cm2/(V·s),an on/off current ratio of 105,a sub-threshold swing of 0.366V/decade,and a threshold voltage of 3.01 V.
引文
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[3]Sang Y L,Chang S,Lee J S.Role of high-kgate insulators for oxide thin film transistors[J].Thin Solid Films,2010,518(11):3030-3032.
[4]Ko J B,Yeom H I,Park S H K.Plasma-enhanced atomic layer deposition processed SiO2gate insulating layer for high mobility top-gate structured oxide thin-film transistors[J].IEEE Electron Device Letters,2016,37(1):39-42.
[5]Choi J H,Mao Y,Chang J P.Development of hafnium based high-k materials—A review[J].Materials Science and Engineering:R:Reports,2011,72(6):97-136.
[6]Ribes G,Mitard J,Denais M,et al.Review on high-kdielectrics reliability issues[J].IEEE Transactions on Device and Materials Reliability,2005,5(1):5-19.
[7]Lee J,Cha J J,Barron S C,et al.Material and electrical characterization of stackable planar polysilicon TFT flash memory cell with metal nanocrystals and high-k dielectrics[C].2008IEEE International SOI Conference Proceedings,2008:39-40.
[8]Xu W,Wang H,Xie F,et al.Facile and environmentally friendly solution-processed aluminum oxide dielectric for lowtemperature,high-performance oxide thin-film transistors[J].ACS Applied Materials&Interfaces,2015,7(10):5803-5810.
[9]Robertson J,Wallace R M.High-k materials and metal gates for CMOS applications[J].Materials Science and Engineering:R:Reports,2015,88:1-41.
[10]Wu J L,Lin H Y,Su B Y,et al.X-ray reflectivity and surface energy analyses of the physical and electrical properties ofα-IGZO/GZO double active layer thin film transistors[J].Ceramics International,2014,40(1):2419-2425.
[11]strand M,Selinder T I,Fietzke F,et al.PVD-Al2O3-coated cemented carbide cutting tools[J].Surface and Coatings Technology,2004,188:186-192.
[12]Lu D Y,Peng Y Y,Yu X Y,et al.Dielectric properties and defect chemistry of La and Tb co-doped BaTiO3ceramics[J].Journal of Alloys and Compounds,2016,681:128-138.
[13]Chen S B,Lai C H,Chin A,et al.High-density MIM capacitors using Al2O3and AlTiOxdielectrics[J].IEEE Electron Device Letters,2002,23(4):185-187.
[14]Zhao Jiaoling,He Hongbo,Wang Hu,et al.Influence of deposition rate on microstructure and optical properties of Mo films fabricated by direct current pulse sputtering[J].Acta Optica Sinica,2016,36(9):0931001.赵娇玲,贺洪波,王虎,等.沉积速率对直流脉冲溅射钼薄膜微结构与光学性能的影响[J].光学学报,2016,36(9):0931001.
[15]Shamala K S,Murthy L C S,Rao K N.Studies on optical and dielectric properties of Al2O3thin films prepared by electron beam evaporation and spray pyrolysis method[J].Materials Science and Engineering:B,2004,106(3):269-274.
[16]Prasanna S,Jayakumar S,Kannan M D,et al.Dielectric properties of DC reactive magnetron sputtered Al2O3thin films[J].Thin Solid Films,2012,520(7):2689-2694.