Y_2O_3改善HfO_2高k栅介质Ge MOS电容的电特性及可靠性  

Improved Electrical Properties and Reliability of Ge MOS Capacitors with HfO_2 High-k Gate Dielectric by Using Y_2O_3 Interlayer

作　　者：徐火希[1] 谢玉林[1,2] 

机构地区：[1]黄冈师范学院电子信息系,湖北黄州438000 [2]华中科技大学国家光电实验室,武汉430074

出　　处：《固体电子学研究与进展》2017年第6期389-394,共6页Research & Progress of SSE

基　　金：湖北省自然科学基金资助项目(2011CDB165);黄冈师范学院科研资助项目(2012028803)

摘　　要：以Y_2O_3薄膜作为夹层,采用磁控溅射法制备了HfO_2/Y_2O_3叠层高k栅介质Ge MOS电容,并对其电特性及高场应力特性进行了仔细研究。结果表明,Y_2O_3夹层能显著地改善Ge MOS器件的界面质量、k值、栅极漏电流特性、频率色散特性和器件可靠性。因此,HfO_2/Y_2O_3/Ge MOS电容表现出较低的界面态密度(6.4×1011 eV^(-1)cm^(-2))、较高的k值(21.6)、较小的栅极漏电流密度(Vg=1V+Vfb时,Jg=1.65×10^(-6) A·cm^(-2))、极小的频率色散以及良好的器件可靠性。其机理在于Y_2O_3夹层能充当阻挡层角色,有效地阻挡了Hf、O与Ge的相互扩散,从而抑制了不稳定低k GeO_x夹层的生长。Ge MOS capacitors with HfO2/Y2O3 stacked high-k gate dielectric were fabricated by using sputtering method and Y2O3 as interlayer and their electrical properties and high-field stress characteristics were carefully investigated and compared.It is found that Y2O3 interlayer can significantly improve the performances of Ge MOS device in terms of interface quality,kvalue,gate-leakage current,frequency-dispersion properties and device reliability.Therefore,HfO2/Y2O3/Ge MOS capacitor exhibits lower interface-state density（6.4×1011 eV-1 cm-2）,higher k value（21.6）,smaller gate-leakage current density（Jg=1.65×10-6 A·cm-2 at Vg=1 V＋Vfb）,very small frequency dispersion and excellent device reliability.The involved mechanism lies in that Y2O3 interlayer can act as a barrier layer and effectively block the inter-diffusions of Hf,O and Ge,thus suppressing the growth of unstable low-k GeOx interlayer.

关 键 词：Ge金属-氧化物-半导体 Y2O3夹层 界面质量 k值 

分 类 号：TN386.1[电子电信—物理电子学]