【作者】 姜昊；

【导师】 杨剑群；

【作者基本信息】 哈尔滨工业大学 ， 材料工程（专业学位）， 2021， 硕士

【摘要】 由于HfO₂材料具有较高的介电常数、较低的泄漏电流,以及与Si材料较好的热匹配性,成为电子器件理想的栅氧介质材料,被广泛应用于航天电子元器件中。电子元器件在轨服役过程中,对空间辐照环境异常敏感,影响其在轨使用可靠性和寿命。迄今,有关HfO₂栅介质材料辐射损伤机制尚不清楚。因此,开展HfO₂栅介质材料辐射损伤效应研究具有重要的工程实际意义和学术价值。本文以不同厚度（10 nm与30 nm）HfO₂基MIS电容器为研究对象,基于不同能量带电粒子及不同剂量率的⁶⁰Co源辐照试验,采用平带和中带电压法、深能级瞬态谱及透射电镜等表征技术,并结合模拟仿真技术,研究了辐射诱导微观缺陷与宏观性能退化的内在联系。研究结果表明,带电粒子辐照导致电容器C-V曲线负向漂移以及泄漏电流增加,VO₃⁰氧空位缺陷导致150 ke V低能电子辐照后C-V曲线出现双向漂移现象。电子和低能质子辐照时HfO₂氧化层遂穿机制分别为电场协助隧穿（FN）和直接遂穿（DT）。在150 ke V低能电子与质子辐照条件下,氧化层越厚越易产生氧化物俘获电荷,越薄越易产生界面陷阱电荷,1 Me V高能电子反之。150 ke V质子辐照在HfO₂氧化层产生位移损伤VO₃^-1氧空位,1 Me V电子辐照导致电容器介电常数变大。通过对比电离和位移损伤效应可知,无论是等电离吸收剂量还是位移吸收剂量下,150 ke V电子对HfO₂基MIS电容器电性能退化以及陷阱电荷密度影响最大,1 Me V次之,150 ke V质子最小。三种辐照源都不存在等效关系。高、低剂量率γ射线辐照导致C-V曲线都沿电压轴负向的漂移,氧化层越薄泄漏电流密度变化越敏感,HfO₂氧化层隧穿机制为（FN）电场协助隧穿。γ射线辐照射诱导陷阱电荷产生与电容器的本征缺陷相关,导致氧化层越厚越易产生界面陷阱电荷。在低剂量率增强效应下,与100 rad（Si）/s高剂量率相比,在27 mrad（Si）/s的低剂量率辐照条件下,氧化物俘获正电荷密度升高1.2倍,界面态电荷密度升高7.7倍。通过电离损伤对比,发现辐照相同电离吸收剂量下,150 ke V电子对HfO₂基MIS电容器电性能退化以及陷阱电荷密度影响远大于高、低剂量率γ射线,且两种辐照源不存在等效关系。更多还原

【Abstract】 Due to it’s high dielectric constant,low leakage current and good thermal matching with Si material,HfO₂ material is an ideal gate oxygen medium material for electronic d e Vices and is widely used in aerospace electronic components.During the in-orbit service,electronic components are extremely sensitive to the space irradiation environment,which affects their in-orbit reliability and life.Up to now,the radiation damage mechanism of HfO₂ gate dielectric materials is not clear.Therefore,the research on radiation damage effect of HfO₂ gate material has important engineering practical significance and academic value.In this paper,HfO₂-Based MIS capacitors with different thicknesses（10nm and 30 nm）were taken as the research object.Based on the ⁶⁰Co source irradiation experiments of charged particles with different energies and different dose rates,flat-band and medium-band voltage methods,DLTS and TEM were adopted,and combined with simulation technology.The internal relationship between radiation induced microdefects and macro performance degradation was studied.The results show that.The radiation of charged particles leads to the negative drift of capacitor C-V curve and the increase of leakage current.The defect of VO₃⁰oxygen vacancy leads to the bidirectional drift of capacitor C-V curve after the radiation of 150ke V low-energy electron.The tunneling mechanism of HfO₂ oxide layer under electron and proton irradiation is Fowler-Nordheim（FN）and Direct Tunneling（DT）respectively.Under the condition of 150 ke V low energy electron and proton irradiation,the thicker the oxide layer is,the more likely it is to produce oxide capture charge,the thinner the oxide layer is,the more likely it is to produce interface trap charge,and the 1Me V high energy electron is the opposite.The proton irradiation of 150 ke V causes displacement damage to the VO₃^-1 oxygen vacancy in the HfO₂ oxide layer,and the electron irradiation of 1 Me V causes the capacitor’s dielectric constant to increase.By comparing the effects of ionization and displacement damage,it is found that the effect of 150 ke V electron on the degradation of HfO₂-based MIS capacitor is the greatest,followed by 1 Me V proton and 150 ke V proton at the same absorption dose and displacement absorption dose.There is no equivalence relation between the three kinds of radiation sources.High and low dose rateγ-ray irradiation results in the negative drift of C-V curves along the voltage axis.The thinner the oxide layer is,the more sensitive the change of leakage current density is.The tunneling mechanism of HfO₂ oxide layer is Fowler-Nordheim（FN）.The trap charge generation induced byγ-ray irradiation is related to the intrinsic defects of the capacitor.The thicker the oxide layer,the easier it is to generate the interface trap charge.Under low dose rate enhancement effect,compared with high dose rate of 100 rad（Si）/s,under low dose rate of 27 mrad（Si）/s irradiation condition,the captured positive charge density of the oxide increases by 1.2 times and the interfacial-state charge density increases by 7.7 times.Through comparison of ionization damage,it is found that the effects of 150ke V electron on the degradation of electrical properties and trap charge density of HfO₂-based MIS capacitor at the same ionization absorption dose are much greater than those ofγ-ray with high and low dose rate,and there is no equivalent relationship between the two radiation sources.更多还原