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1.
The role of N2 on GaAs etching at 150 mTorr capacitively-coupled Cl2/N2 plasma is reported. A catalytic effect of N2 was found at 20-25% N2 composition in the Cl2/N2 discharges. The peak intensities of the Cl2/N2 plasma were monitored with optical emission spectroscopy (OES). Both atomic Cl (725.66 nm) and atomic N (367.05 nm) were detected during the Cl2/N2 plasma etching. With the etch rate and OES results, we developed a simple model in order to explain the etch mechanism of GaAs in the high pressure capacitively-coupled Cl2/N2 plasma as a function of N2 ratio. If the plasma chemistry condition became positive ion-deficient at low % N2 or reactive chlorine-deficient at high % N2 in the Cl2/N2 plasma, the GaAs etch rate is reduced. However, if the plasma had a more balanced ratio of Cl2/N2 (i.e. 20-25% N2) in the plasma, much higher etch rates (up to 150 nm/min) than that in pure Cl2 (50 nm/min) were produced due to synergetic effect of neutral chlorine adsorption and reaction, and positive ion bombardment. Pure Cl2 etching produced 14 nm of RMS surface roughness of GaAs. Introduction of ?20% N2 gas in Cl2/N2 discharges significantly reduced the surface roughness to 2-4 nm. SEM photos showed that the morphology of photoresist mask was strongly degraded. Etch rate of GaAs slightly increased from 10 to 40 nm/min when RIE chuck power changed from 10 to 150 W at 12 sccm Cl2/8 sccm N2 plasma condition. The surface roughness of GaAs etched at 12 sccm Cl2/8 sccm N2 plasma was 2-3 nm. 相似文献
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基于HfO2的铁电随机存取存储器(FeRAM)具有功耗低、存取速度快,易于小型化,抗干扰能力强等优势,在航天航空领域有广袤的发展空间。然而,FeRAM在太空环境下的抗辐照性能尚未得到全面的研究。研究了W/TiN/Hf0.5Zr0.5O2(HZO)/TiN铁电存储器在常温和高温环境下经5 MeV质子辐照后的电学特性和铁电畴结构变化。通过电学和压电响应力显微镜(PFM)手段表征发现,在常温质子辐照后,电容器的介电常数(εr)和剩余极化强度(Pr)值均增大,器件的铁电性能提升,常温高注量质子辐照有利于存储器在太空环境中工作,但随着辐照时环境温度升高,HZO存储器的铁电性能下降,漏电流增大,铁电存储器的各项性能明显退化。 相似文献
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In this paper, we report our recent study of the effect of RuO2 as an alternative top electrode for pMOS devices to overcome the serious problems of polysilicon (poly-Si) gate depletion, high gate resistance and dopant penetration in the trend of down to 50 nm devices and beyond. The conductive oxide RuO2, prepared by RF sputtering, was investigated as the gate electrode on the Laser MBE (LMBE) fabricated HfO2 for pMOS devices. Structural, dielectric and electric properties were investigated. RuO2/HfO2/n-Si capacitors showed negligible flatband voltage shift (<10 mV), very strong breakdown strength (>10 MV cm−1). Compared to the SiO2 dielectric with the same EOT value, RuO2/HfO2/n-Si capacitors exhibited at least 4 orders of leakage current density reduction. The work function value of the RuO2 top electrode was calculated to be about 5.0 eV by two methods, and the effective fixed oxide charge density was determined to be 3.3 × 1012 cm−2. All the results above indicate that RuO2 is a promising alternative gate electrode for LMBE grown HfO2 gate dielectrics. 相似文献
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The HfO2 high-k thin films have been deposited on p-type (1 0 0) silicon wafer using RF magnetron sputtering technique. The XRD, AFM and Ellipsometric characterizations have been performed for crystal structure, surface morphology and thickness measurements respectively. The monoclinic structured, smooth surface HfO2 thin films with 9.45 nm thickness have been used for Al/HfO2/p-Si metal-oxide-semiconductor (MOS) structures fabrication. The fabricated Al/HfO2/Si structure have been used for extracting electrical properties viz dielectric constant, EOT, barrier height, doping concentration and interface trap density through capacitance voltage and current-voltage measurements. The dielectric constant, EOT, barrier height, effective charge carriers, interface trap density and leakage current density are determined are 22.47, 1.64 nm, 1.28 eV, 0.93 × 1010, 9.25 × 1011 cm−2 eV−1 and 9.12 × 10−6 A/cm2 respectively for annealed HfO2 thin films. 相似文献
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Ho Jin Cho Young Dae Kim Dong Su Park Euna Lee Cheol Hwan Park Jun Soo Jang Keum Bum Lee Hai Won Kim Young Jong Ki Il Keun Han Yong Wook Song 《Solid-state electronics》2007,51(11-12):1529
New ZrO2/Al2O3/ZrO2 (ZAZ) dielectric film was successfully developed for DRAM capacitor dielectrics of 60 nm and below technologies. ZAZ dielectric film grown by ALD has a mixture structure of crystalline phase ZrO2 and amorphous phase Al2O3 in order to optimize dielectric properties. ZAZ TIT capacitor showed small Tox.eq of 8.5 Å and a low leakage current density of 0.35 fA/cell, which meet leakage current criteria of 0.5 fA/cell for mass production. ZAZ TIT capacitor showed a smaller cap leak fail bit than HAH capacitor and stable leakage current up to 550 °C anneal. TDDB (time dependent dielectric breakdown) behavior reliably satisfied the 10-year lifetime criteria within operation voltage range. 相似文献
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Present study reports the variation of structural and optical properties of N implanted ZnSe single crystals grown by a Chemical Vapor Transport (CVT) technique due to120 MeV Au ion irradiation. The grazing incidence X-ray diffraction (GIXRD) results show that the full width at half maximum (FWHM) increases on irradiation. The surface morphology of irradiated sample shows the pits and islands by AFM studies. The optical absorption cut off wavelength is 493 nm for as grown ZnSe whereas for the implanted and irradiated samples cut off wavelength shift towards red region. The photoluminescence spectrum shows the emission wavelength is at 592 nm whereas for the implanted-irradiated samples PL emission shift towards red region. The intensity of defect level emission decreases due to Au irradiation. The FT-Raman spectrum shows the peak at 252 cm−1 due to LO mode of Zn–Se lattice vibrations. The X-ray absorption near edge structure (XANES) study was performed for the as grown and irradiated samples. The detailed investigation on the structural and optical properties of the N implanted and Au irradiated ZnSe single crystal was carried out. 相似文献
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Shang-Chou Chang Tien-Chai Lin To-Sing Li Sheng-Han Huang 《Microelectronics Journal》2008,39(12):1572-1575
To find the possibility of using a low-temperature process in growing carbon nanotubes (CNTs), nickel catalyst converted from film into particles by microwave H2/N2 plasma and the following CNT growth are all kept at a low temperature of 250 °C. The flat panel display industry requests low-temperature rather than the traditional high-temperature process for CNT growth. It was found that H2/N2 proportion is very sensitive to nickel morphology and the subsequent CNT growth. Better nickel and CNTs morphology are obtained for the proportion H2/N2=3/1 than those for the generally used pure hydrogen environment. The process pressure selection during pretreatment can determine whether CNTs are grown or not. The diameter of growing CNTs is proportional to nickel particle size. Field emission results support field amplification coefficient claim. The long tube length and high tube density of growing CNTs demonstrate low threshold electric field. This work shows the potential to use H2/N2 instead of pure hydrogen plasma in growing qualified CNTs applied in display industry. 相似文献
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电子束辐照下的石墨烯上的原子层沉积Al2O3介质层 总被引:1,自引:1,他引:0
为了研究石墨烯与高k介质的结合,使用原子层沉积氧化铝在石墨衬底上。沉积前使用电子束辐照,观测到了氧化铝明显改善的形貌。归因于电子束辐照过程中的石墨层的无定形变化过程。 相似文献
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Tl3InSe4 single crystal has been successfully prepared by the Bridgman crystal growth technique. The crystal that is reported for the first time is found to be of tetragonal structure with lattice parameters of a=0.8035 and c=0.6883 nm. The electrical resistivity and Hall effect measurements on the crystal revealed a conductivity type conversion from p- to n-type at a critical temperature of 283 K. The electron to hole mobility ratio is found to be 1.10. The analysis of the temperature-dependent electrical resistivity, Hall coefficient and carrier concentration data reveals the extrinsic type of conduction with donor impurity levels that behave as acceptor levels when are empty. The data analysis allowed the calculation of the hole and the electron effective masses as 0.654m0 and 0.119m0, respectively. In addition, the temperature-dependent Hall mobility in the n-region is found to be limited by the electron–phonon short-range interactions scattering with an electron–phonon coupling constant of 0.21. 相似文献
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本文中, 使用开尔文探针显微镜,研究了不同退火气氛(氧气或氮气)情况下氧化铪材料的电子和空穴的电荷保持特性。与氮气退火器件相比,氧气退火可以使保持性能变好。横向扩散和纵向泄露在电荷泄露机制中都起了重要的作用。 并且,保持性能的改善与陷阱能级深度有关。氮气和氧气退火情况下,氧化铪存储结构的的电子分别为0.44 eV, 0.49 eV,空穴能级分别为0.34 eV, 0.36 eV。 最后得到,不同退火气氛存储器件的电学性能也与KFM结果一致。对于氧化铪作为存储层的存储器件而言,对存储特性的定性和定量分析,陷阱能级,还有泄漏机制研究是十分有意义的。 相似文献
12.
R. Knizikevi?ius 《Microelectronic Engineering》2009,86(1):55-58
The reactive ion etching (RIE) of SiO2 in CF4 + H2 plasma is considered. The influence of activated polymer on the RIE rate of SiO2 in CF4 + H2 plasma is determined by extrapolation of experimentally measured kinetics of the etching rate. It is found that the increased surface coverage by CF2 radicals suppresses the RIE rate of SiO2 in CF4 + H2 plasma during the initial stages of the etching process. The formation of activated polymer becomes pronounced when adsorbed CF2 radicals are slowly activated. The activated polymer intensifies the etching reaction and enhances the etching rate. At the same time, the activated polymer intensifies the polymerization reactions. The increased surface coverage by the polymer suppresses the RIE rate of SiO2 in CF4 + H2 plasma at later stages of the etching process. 相似文献
13.
近年来,氧化铪基忆阻器因其优异的阻变性能及与CMOS工艺兼容等特点而被广泛研究。然而,氧化铪基忆阻器仍存在以下问题:1) 器件良率、可靠性、均一性不足;2) Set和Reset 过程中电流突变,导致多值特性较差。为实现氧化铪基忆阻器的性能优化及多值特性,文章在HfO2表面生长一层1~5 nm Al2O3,构造Al2O3/HfO2双介质层忆阻器,并对HfO2和Al2O3的厚度进行优化,最终得到性能显著提升的Al2O3/HfO2双介质层多值忆阻器。该器件呈现出保持性良好的10个不同电阻态(1×104 s@85℃)。由于氧离子在Al2O3层的迁移率更低,限制了氧空位细丝生长速率及宽度,且Al2O3具有热增强作用,使氧空位分布更均匀,促使氧空位细丝生成/断裂过程由突变转为渐变。该工作为进一步实现氧化铪基忆阻器的性能优化及多值特性提供了参考。 相似文献
14.
Yung-Hsien Wu Lun-Lun ChenWei-Chia Chen Chia-Chun LinMin-Lin Wu Jia-Rong Wu 《Microelectronic Engineering》2011,88(7):1361-1364
A Ge-stabilized tetragonal ZrO2 (t-ZrO2) film with permittivity (κ) of 36.2 was formed by depositing a ZrO2/Ge/ZrO2 laminate and a subsequent annealing at 600 °C, which is a more reliable approach to control the incorporated amount of Ge in ZrO2. On Si substrates, with thin SiON as an interfacial layer, the SiON/t-ZrO2 gate stack with equivalent oxide thickness (EOT) of 1.75 nm shows tiny amount of hysteresis and negligible frequency dispersion in capacitance-voltage (C-V) characteristics. By passivating leaky channels derived from grain boundaries with NH3 plasma, good leakage current of 4.8 × 10−8 A/cm2 at Vg = Vfb − 1 V is achieved and desirable reliability confirmed by positive bias temperature instability (PBTI) test is also obtained. 相似文献
15.
In2O3-Fe2O3 nanotubes are synthesized by an electrospinning method. The as-synthesized materials are characterized by scanning electron microscope and X-ray powder diffraction. The gas sensing results show that In2O3-Fe2O3 nanotubes exhibit excellent sensing properties to acetone and formaldehyde at different operating temperatures. The responses of gas sensors based on In2O3-Fe2O3 nanotubes to 100 ppm acetone and 100 ppm formaldehyde are 25 (240℃) and 15 (260℃), and the response/recovery times are 3/7 s and 4/7 s, respectively. The responses of In2O3-Fe2O3 nanotubes to 1 ppm acetone (240℃) and formaldehyde (260℃) are 3.5 and 1.8, respectively. Moreover, the gas sensor based on In2O3-Fe2O3 nanotubes also possesses an excellent selectivity to acetone and formaldehyde. 相似文献
16.
Shaibal Mukherjee D. LiG. Bi J. MaS.L. Elizondo A. GautamZ. Shi 《Microelectronic Engineering》2011,88(3):314-317
A new method of surface passivation of PbSe epitaxial layers by growing a thin epitaxial CaF2 layer is proposed. Improvement in photoluminescence (PL) intensity is observed when the PbSe layer is passivated. The minority carrier lifetime (τ), measured by photo-current decay method corroborates PL measurements and shows a consistent, albeit not considerable, improvement in the lifetime of PbSe samples after surface passivation. The positive effect of surface passivation, especially at low heat-sink temperature, offered by a new passivating material is critically important for IV-VI material-based infrared detector and sensor applications. 相似文献
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Thierno Sall A. Nafidi Bernab Mar Soucase Miguel Mollar Bouchaib Hartitti Mounir Fahoume 《半导体学报》2014,35(6):063002-5
Indium sulfide (InzS3) thin films were prepared by chemical spray pyrolysis technique from solutions with different [S]/[In] ratios on glass substrates at a constant temperature of 250 ~C. Thin films were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), atomic force microscopy (AFM), energy disper- sive X-ray spectroscopy (EDS), Raman spectroscopy and optical transmittance spectroscopy. All samples exhibit a polycrystalline structure with a preferential orientation along (0, 0, 12). A good stoichiometry was attained for all samples. The morphology of thin film surfaces, as seen by SEM, was dense and no cracks or pinholes were ob- served. Raman spectroscopy analysis shows active modes belonging to j3-1naS3 phase. The optical transmittance in the visible range is higher than 60% and the band gap energy slightly increases with the sulfur to indium ratio, attaining a value of 2.63 eV for [S]/[In] : 4.5. 相似文献