Evidence of GeO volatilization and its effect on the characteristics of HfO_2 grown on a Ge substrate  

作　　者：樊继斌 刘红侠 费晨曦 马飞 范晓娇 郝跃 

机构地区：[1]School of Microelectronics,Key Laboratory of Wide Band-Gap Semiconductor Materials and Devices,Xidian University

出　　处：《Chinese Physics B》2013年第3期501-504,共4页中国物理B（英文版）

基　　金：Project supported by the National Natural Science Foundation of China (Grant Nos. 60976068 and 61076097);the Cultivation Fund of the Key Scientific and Technical Innovation Project of the Ministry of Education of China (Grant No. 708083)

摘　　要：HfO2 films are deposited by atomic layer deposition（ALD） using tetrakis ethylmethylamino hafnium（TEMAH） as the hafnium precursor,while O3 or H2O is used as the oxygen precursor.After annealing at 500℃ in nitrogen,the thickness of Ge oxide＇s interfacial layer decreases,and the presence of GeO is observed at the H2 O-based HfO2 interface due to GeO volatilization,while it is not observed for the O3-based HfO2.The difference is attributed to the residue hydroxyl groups or H2 O molecules in H2 O-based HfO2 hydrolyzing GeO2 and forming GeO,whereas GeO is only formed by the typical reaction mechanism between GeO2 and the Ge substrate for O3-based HfO2 after annealing.The volatilization of GeO deteriorates the characteristics of the high-κ films after annealing,which has effects on the variation of valence band offset and the C-V characteristics of HfO2 /Ge after annealing.The results are confirmed by X-ray photoelectron spectroscopy（XPS） and electrical measurements.HfO2 films are deposited by atomic layer deposition（ALD） using tetrakis ethylmethylamino hafnium（TEMAH） as the hafnium precursor,while O3 or H2O is used as the oxygen precursor.After annealing at 500℃ in nitrogen,the thickness of Ge oxide＇s interfacial layer decreases,and the presence of GeO is observed at the H2 O-based HfO2 interface due to GeO volatilization,while it is not observed for the O3-based HfO2.The difference is attributed to the residue hydroxyl groups or H2 O molecules in H2 O-based HfO2 hydrolyzing GeO2 and forming GeO,whereas GeO is only formed by the typical reaction mechanism between GeO2 and the Ge substrate for O3-based HfO2 after annealing.The volatilization of GeO deteriorates the characteristics of the high-κ films after annealing,which has effects on the variation of valence band offset and the C-V characteristics of HfO2 /Ge after annealing.The results are confirmed by X-ray photoelectron spectroscopy（XPS） and electrical measurements.

关 键 词：GeO volatilization H2 O-based HfO2 O3-based HfO2 thermal stability 

分 类 号：TN304.055[电子电信—物理电子学]