微波退火对高k/金属栅中缺陷的修复

研究了微波退火(MWA)对高k/金属栅中缺陷的修复作用。在频率为1和100 kHz下,对所有Mo/HfO2/Si(100)金属-绝缘体-半导体(MIS)结构样品进行C-V特性测试。通过在频率为100 kHz下测量的C-V特性曲线提取出平带电压与电压滞回窗口,从而估算出高k/金属栅中固定电荷密度和电荷陷阱密度,并用Terman方法计算出快界面态密度。通过研究在频率为1 kHz下测量的C-V特性曲线扭结,定性描述高k/金属栅中的慢界面态密度。结果表明,微波退火后,固定电荷、电荷陷阱、快界面态和慢界面态得到一定程度的修复。此外,和快速热退火相比,在相似的热预算下,微波退火可修复高k/金属栅中更多的固定电荷、慢界面态和电荷陷阱。但对于快界面态的修复,微波退火没有明显的优势。     

界面陷阱分布对SiC MOSFET准静态C-V特性的影响

为了分析4H-SiC/SiO₂固定电荷和界面陷阱对MOSFET准静态电容-电压(C-V)特性曲线的影响机制，对不同栅氧氮退火条件下的n沟道4H-SiC双注入MOSFET(DIMOSFET)进行了氧化层中可动离子、界面陷阱分布和准静态C-V特性曲线的测试，并结合仿真探讨了测试频率、固定电荷、4H-SiC/SiO₂界面陷阱分布对准静态C-V特性曲线的影响。实验和仿真结果表明：电子和空穴界面陷阱分别影响准静态C-V曲线的右半部分和左半部分；界面陷阱的E₀、E_s、N₀(E₀为陷阱能级中心与导带底能级或价带顶能级之差，E_s为陷阱能级分布的宽度，N₀为陷阱能级分布的密度峰值)对准静态C-V曲线的影响是综合的；当E₀为0 eV,E_s为0.2 eV,电子和空穴捕获截面均为1×10^-18 cm²,电子和空穴界面陷阱的N₀分...     

影响Ar~+激光再结晶多晶硅/二氧化硅界面性质的因素

本文就Ar~+激光辐照功率、衬底温度等因素对SOI结构再结晶多晶硅/二氧化硅界面性质的影响进行研究,利用高频和准静态C-V技术测量该界面氧化物固定电荷密度N_t和界面态陷阱密度N_(it),用平面和剖面TEM分析再结晶多晶硅膜的结构特性,我们发现当衬底温度为 320℃和420℃时存在一个功率窗口 6.0～6.2W.     

阳极氧化Al_2O_3膜/InP和自身氧化膜/InP的界面性质

研究了用阳极氧化法制备的Al_2O_3膜/InP和自身氧化膜/InP两种MIS结构的组分分布和电学性质,AES、I-V、C-V和DLTS等测试结果表明,Al_2O_3/InP结构的性能更为优越.用DLTS方法发现这两类样品都具有峰值能量为Ec-Es=0.5eV、俘获截面为～10~(-15)cm~2的连续分布的界面电子陷阱.认为该电子陷阱与磷空位缺陷有关.     

原子层沉积Al_2O_3/n-GaN结构的深能级界面态研究

基于与传统方法不同的物理过程,利用光辅助高频电容-电压(C-V)法研究了原子层沉积的Al_2O_3/nGaN界面的深能级缺陷态分布。无光照条件下的C-V曲线表现出典型的深耗尽行为,这主要由极长的深能级电子发射时间和极慢的少子热产生速率决定,可看作向正偏压方向平移了的理想电容曲线。在深耗尽状态下背入射365nm的紫外光后,大量的光生空穴有效地复合准费米能级以上的界面被陷电子,并允许电子在偏压扫描回积累区的过程中逐渐填充这些被排空的界面态,导致C-V曲线发生形变。基于上述物理过程,获得了一个快速衰减的界面态能级分布:从导带底至以下0.8eV,态密度从2.5×10~(12)cm~(-2)eV~(-1)减小至9×10~(10)cm~(-2)eV~(-1)。     

中波碲镉汞/钝化层界面电学特性研究

HgCdTe表面/界面特性对器件性能具有重要的影响,表面/界面的状态主要依赖于表面处理和钝化工艺。采用Br2/CH3OH腐蚀液对液相外延(LPE)生长的中波HgCdTe薄膜进行表面处理后,使用Cd Te/Zn S复合钝化技术进行表面钝化,制备了相应的MIS器件并进行器件C-V测试。结果表明,HgCdTe/钝化层界面固定电荷极性为正,面密度为2.1×1011 cm-2,最低快界面态密度为1.43×1011 cm-2·e V-1,在10 V栅压极值下慢界面态密度为4.75×1011 cm-2,较低的快界面态密度体现出了CdTe/ZnS复合钝化技术的优越性。     

In Sb MOS电容器高频C-V特性的测量及其界面态密度的推算

本实验首先测量了N型、(111)面、掺Te2×10~(15)cm~(-3)InSb晶片的机械损伤层,然后用阳极氧化等方法将其做成MOS结构,测量和分析其高频C-V特性,并采用中心偏压加窄摆幅电压的来回慢扫测得无滞回效应的C-V曲线。最后,用Nakagawa式算出界面态密度为2×10~(12)cm~(-2)eV~(-1)。     

肖特基C-V法研究AlxGa1-xN/GaN异质结界面二维电子气

通过对Pt/AI0 22Ga078N/GaN肖特基二极管的C-V测量,研究分析了A1022Ga078N/GaN异质结界面二维电子气(2DEG)浓度及其空间分布.测量结果表明,Al0.22Ga.8N/GaN异质结界面2DEG浓度峰值对应的深度在界面以下1.3nm处,2DEG分布峰的半高宽为2.3nm,2DEG面密度为6.5×1012cm-2.与AlxGa1xAs/GaAs异质结比,其2DEG面密度要高一个数量级,而空间分布则要窄一个数量级.这主要归结于A1xGa1-xN层中～MV/cm量级的压电极化电场和自发极化电场对AlxGa1-xN/GaN异质结能带的调制和AlxGa1xN/GaN异质结界面有更大的导带不连续.     

电离辐射对Si_3N_4/SiO_2/Si双界面系统的作用

采用氩离子刻蚀XPS(X光激发电子能谱)分析对S i3N4/S iO2/S i双界面系统进行了电离辐照剖面分析。实验结果表明:电离辐照能将S iO2和S i构成的界面区中心向S i3N4/S iO2界面方向推移,同时S iO2/S i界面区亦被电离辐照展宽。在同样偏置电场中辐照,随着辐照剂量的增加电离辐照相当程度地减少位于S iO2/S i界面区S i3N4态(结合能B.E.101.8 eV)S i的浓度。同时辐照中所施偏置电场对S iO2/S i界面区S i3N4态键断开有显著作用。文中就实验现象的机制进行了初步探讨。     

固体C70/Si异质结的界面电子态

用深能级瞬态谱和高频电容-电压技术研究了固体C70/Si异质结的界面电子态.研究结果表明在C70/Si的界面上明显存在三个电子陷阱Eit1(0.194)、Eit2(0.262),Eit3(0.407)和一个空穴陷阱Hit1(0.471),以及在C70/Si界面附近存在着固体C70的电子和空穴陷阱引起的慢界面态.结果还表明C70膜的生长温度对C70/Si的电学性质有重大影响,200℃生长的C70/Si界面远优于室温生长的.     

Aluminum Nitride Films Fabricated by Mid-frequency Magnetron Sputtering

Aluminum nitride films were prepared by mid-frequency magnetron sputtering on Si (111) substrate. The grown films were characterized by X-ray diffraction(XRD), scanning electron microscopy(SEM) and X-ray photoelectron spectroscopy(XPS) to obtain the structural and the chemical information. The polycrystalline thin films were in a hexagonal wurtzite structure having a (002) preferred orientation, along which the columnar grain structure was found. XPS study revealed the presence of oxygen and carbon contaminations, as well as the Al-rich nature of the film. Anomalous C-V characteristics of Al/AlN/n-Si capacitors were studied. The measured C-V curves show rolloffs in the accumulation region and voltage stresses cause both horizontal and vertical shifts of the C-V curves. These anomalous behaviors are mainly due to the large current conduction and the charge trapping in the Al-rich AlN layer.     

氢化非晶碳膜与硅的界面特性

利用直流辉光放电分解碳氢气体来淀积ａ－Ｃ：Ｈ膜，通过测量Ａｌ／ａ－Ｃ：Ｈ／ＳｉＭＩＳ结构的高频Ｃ－Ｖ曲线讨论了ａ－Ｃ：Ｈ／Ｓｉ界面的电子特性，结果表明ａ－Ｃ：Ｈ／Ｓｉ膜有可能用作半导体器件的表面钝化膜。     

Characteristics of Si3N4/GaAs metal-lnsulator-semiconductor interfaces with coherent Si/Al0.3Ga0.7As interlayers

Si₃N₄/GaAs metal-insulator-semiconductor (MIS) interfaces with Si(10Å)/ Al_0.3Ga_0.7As (20Å) interface control layers have been characterized using capacitance-voltage (C-V) and conductance methods. The structure was in situ grown by a combination of molecular beam epitaxy and chemical vapor deposition. A density of interface states in the 1.1 × 10¹¹ eV^-1 cm^-2 range near the GaAs midgap as determined by the conductance loss has been attained with an ex situ solid phase annealing of 600°C in N₂ ambient. A dip quasi-static C-V demonstrating the inversion of the minority-carrier verifies the decent interface quality of GaAs MIS interface. The hysteresis and frequency dispersion of the MIS capacitors were lower than 100 mV, some of them as low as 50 mV under a field swing of about ±2 MV/cm. The increase of the conductance loss at higher frequencies was observed when employing the surface potential toward conduction band edge, suggesting the dominance of faster traps. Self-aligned gate depletion mode GaAs metal-insulator-semiconductor field-effect transistors with Si/Al_0.3Ga_0.7As interlayers having 3 μm gate lengths exhibited a transconductance of about 114 mS/mm. The present article reports the first application of pseudomorphic Si/ Al_0.3Ga_0.7As interlayers to ideal GaAs MIS devices and demonstrates a favorable interface stability.     

Ta2O5高k介电薄膜的制备及其电学性质的研究

用射频磁控溅射法制备了Ta2O5高介电薄膜,并对其进行了退火处理。用C-V,(G/ω)-V和I-V方法研究了Al/Ta2O5/p-Si结构的电学特性,观测到了C-V和(G/ω)-V的频散效应。认为串联电阻、Si/Ta2O5界面的界面态密度、边缘俘获是频散效应的主要原因,提取了界面态密度和边缘俘获电荷的大小。同时也研究了不同的退火温度对这些参数以及漏电流的影响,经600℃退火后,样品的电容最大,俘获电荷密度和漏电流最小,器件的电学性能最佳。     

Electrical conduction and dielectric breakdown in aluminum oxideinsulators on silicon

Leakage currents and dielectric breakdown were studied in MIS capacitors of metal-aluminum oxide-silicon. The aluminum oxide was produced by thermally oxidizing AlN at 800-1160°C under dry O₂ conditions. The AlN films were deposited by RF magnetron sputtering on p-type Si (100) substrates. Thermal oxidation produced Al ₂O₃ with a thickness and structure that depended on the process time and temperature. The MIS capacitors exhibited the charge regimes of accumulation, depletion, and inversion on the Si semiconductor surface. The best electrical properties were obtained when all of the AlN was fully oxidized to Al₂O₃ with no residual AlN. The MIS flatband voltage was near 0 V, the net oxide trapped charge density, Q_0x, was less than 10¹¹ cm ^-2, and the interface trap density, D_it, was less than 10¹¹ cm^-2 eV^-1, At an oxide electric field of 0.3 MV/cm, the leakage current density was less than 10^-7 A cm^-2, with a resistivity greater than 10 ¹² Ω-cm. The critical field for dielectric breakdown ranged from 4 to 5 MV/cm. The temperature dependence of the current versus electric field indicated that the conduction mechanism was Frenkel-Poole emission, which has the property that higher temperatures reduce the current. This may be important for the reliability of circuits operating under extreme conditions. The dielectric constant ranged from 3 to 9. The excellent electronic quality of aluminum oxide may be attractive for field effect transistor applications     

High quality silicon nitride deposited by Ar/N2/H2/SiH4 high-density and low energy plasma at low temperature

The high-quality PECVD silicon nitride has been deposited by high-density and low-ion-energy plasma at 400 °C and the effect of the process parameters, such as silane and nitrogen flow rate, pressure, on its structure and electrical properties has been investigated. The experimental results show that silane flow rate is the most sensitive parameter for determining deposition rate and N/Si atomic ratio of silicon nitride in the range of process parameters employed. The change of nitrogen flow rate leaded to slightly change in deposition rate, however, it effects significantly on the refractive index or densification of silicon nitride. With the addition of hydrogen gas in plasma, the hysteresis of C-V characteristics of MIS structure decreases from 0.4 to 0.1 V. The moderate increment of ion energy makes further reduction in the hysteresis of C-V characteristics of MIS from 0.1 V to below 0.05 V. The interface trap density of 6.2×10¹⁰ (ev⁻¹ cm^-2), deduced from the high frequency and quasistatic C-V characteristics of the MIS structure, is about the same as that of LPECVD silicon nitride deposited at the range of 750-850 °C. The stoichiometric silicon nitride of excellence electric and structural properties is obtained by Ar/N₂/H₂/SiH₄ high-density and low ion energy plasma.     

Electrical properties of ZnO Nano-particles embedded in polyimide

The ZnO nano-particles were made in the polyimide dielectric matrix by using the chemical reaction between the zinc metal film and polyamic acid. The concentration of the ZnO particle is about 1.5×10¹² cm⁻², with average size below 10 nm, and its shapes are almost spherical. Then, the polyimide layer is a stable dielectric material with a dielectric constant of 2.9. To investigate the electrical properties of ZnO particles in the polyimide insulator film, we fabricated a metal-insulator-semiconductor (MIS) structure and measured capacitance-voltage (C-V) with temperature modulation. At room temperature, C-V hysteresis with a voltage gap of 2.8 V appeared in the MIS structure using SiO₂/Si substrate. As the measuring temperature decreased, the C-V curves were shifted slightly to the accumulation region with gate bias. It was considered that the electrical charging may occur dominantly in nanoparticles, having only a few defects at the interface of the polyimide/SiO₂ and the polyimide/ZnO.     

激光熔蚀反应淀积AlN薄膜残余应力及热稳定性的研究

激光熔蚀反应淀积于 Si(10 0 ) ,Si(111)基底上的 Al N薄膜是高质量高取向性的 Al N多晶膜 ,薄膜与基底的取向关系为 Al N(10 0 )∥ Si(10 0 ) ,Al N(110 )∥ Si(111)。薄膜具有较低的残余应力和较好的热稳定性。实验结果表明 ,当氮气压强和放电电压分别为 10 0× 133.33Pa和 6 50 V时 ,薄膜的残余应力低于 3GPa。此样品在纯氧环境 50 0℃时 ,经过 3h的退火 ,红外吸收谱检测未发现有Al2 O3 特征峰出现。对 Al N/Cu双层膜的研究表明所制备的 Al N薄膜在金属薄膜的防护上也有潜在的应用价值。     

PZT铁电场效应晶体管电学性能

采用磁控溅射法制备了(111)向择优的Pb(Zr0.52Ti0.48)O3(PZT)铁电薄膜,并结合半导体集成技术制备了金属/铁电/金属/多晶硅/绝缘层/Si衬底(MFMIS)结构的n沟道铁电场效应晶体管.研究了铁电场效应晶体管的C-V特性、I-V特性以及写入速度.顺时针的C-V滞回曲线和逆时针的Id-Vg滞回曲线表明,n沟道PZT铁电场效应晶体管具有极化存储性能和明显的栅极化调制效应,并且在-5V到 5V的Vg电压下从C-V和Id-Vg滞回曲线中都得到了2V的存储窗口.     

NH3等离子体钝化对Al2O3/SiGe界面的影响

研究了不同条件的非原位NH_3等离子体钝化对Al_2O_3/SiGe/Si结构界面组分的影响。在p型Si(100)衬底上外延一层30 nm厚的应变Si_0.7Ge_0.3,采用双层Al_2O_3结构,第一层1 nm厚的Al_2O_3薄膜为保护层,之后使用非原位NH_3等离子体分别在300和400℃下对Al_2O_3/SiGe界面进行不同时间和功率的钝化处理,形成硅氮化物(SiN_xO_y)和锗氮化物(GeN_xO_y)的界面层。通过X射线光电子能谱(XPS)分析表面的物质成分,结果表明NH_3等离子体钝化在界面处存在选择性氮化,更倾向于与Si结合从而抑制Ge形成高价态,这种选择性会随着时间的增加、功率的增高和温度的升高变得更加明显。