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1.
A. Srivastava R. K. Nahar C. K. Sarkar 《Journal of Materials Science: Materials in Electronics》2011,22(7):882-889
The effect of rapid thermal annealing on structural and electrical properties of high k HfO2 thin films is investigated. The films were initially deposited at pre-optimized sputtering voltage of 0.8 kV and substrate
bias of 80 V in order to get optimized results for oxide charges and leakage current as a MOS device. The film properties
were investigated for optimum annealing temperature in oxygen and optimum rapid thermal annealing temperature in nitrogen
respectively to get the best electrical results as a MOS device structure. The film thickness, composition and microstructure
is studied by Laser Ellipsometry, XRD and AFM and the effect of thermal annealing is shown. The electrical I–V and C–V characteristics
of the annealed dielectric film were investigated employing Al-HfO2-Si MOS capacitor structure. The flat-band voltage (V
fb) and oxide-charge density (Q
ox) were extracted from the high-frequency C–V curve. Dielectric study were further carried out on HfO2 thin films having metal–insulator–metal (MIM) configuration over a wide temperature (300–500 K) and frequency (100 Hz to
1 MHz) range. 相似文献
2.
Y. K. Lu X. F. Chen W. Zhu R. Gopalkrishnan 《Journal of Materials Science: Materials in Electronics》2006,17(9):685-688
The HfO2 gate dielectric films were fabricated by the laser molecular beam epitaxy (LMBE) technique. High-resolution transmission
electron microscopy (HRTEM) observation showed that under optimized condition, there is no detectable SiO2 interfacial layer in the as-deposited film and a SiO2 interfacial layer of about 0.4 nm was formed at the Si interface due to the post deposition annealing. Capacitance–voltage
(C–V) measurement of the film revealed that the equivalent oxide thickness was about 1.3 nm. Such a film showed very low leakage
current density of 1.5 × 10−2 A cm−2 at 1 V gate bias from the current–voltage (I–V) analysis. The conduction mechanisms as a function of temperature T and electric field E were also systematically studied. 相似文献
3.
Metal–oxide–semiconductor (MOS) capacitors incorporating HfO2 and SrHfON gate dielectrics were fabricated by magnetron sputtering. The interface quality, thermal stability, and electrical properties of the MOS capacitors have been investigated. Compared to HfO2 dielectric film, SrHfON dielectric film has thin interface layer with Si substrate, good thermal stability, and low leakage current densities. The dominant current conduction mechanisms (CCMs) of HfO2 film are Schottky emission or Poole–Frenkel emission at low and high electric fields. The main CCMs of SrHfON film are Schottky emission or Poole–Frenkel emission at low electric field, whereas, the CCMs are replaced by space charge limited current at high electric field. 相似文献
4.
A. Srivastava O. Mangla R. K. Nahar V. Gupta C. K. Sarkar 《Journal of Materials Science: Materials in Electronics》2014,25(8):3257-3263
The electrical properties of hafnium oxide (HfO2) gate dielectric as a metal–oxide–semiconductor (MOS) capacitor structure deposited using pulse laser deposition (PLD) technique at optimum substrate temperatures in an oxygen ambient gas are investigated. The film thickness and microstructure are examined using ellipsometer and atomic force microscope (AFM), respectively to see the effect of substrate temperatures on the device properties. The electrical J–V, C–V characteristics of the dielectric films are investigated employing Al–HfO2–Si MOS capacitor structure. The important parameters like leakage current density, flat-band voltage (Vfb) and oxide-charge density (Qox) for MOS capacitors are extracted and investigated for optimum substrate temperature. Further, electrical studies of these MOS capacitors have been carried out by incorporating La2O3 into HfO2 to fabricate HfO2/La2O3 dielectric stacks at an optimized substrate temperature of 800 °C using a PLD deposition technique under oxygen ambient. These Al–HfO2–La2O3–Si dielectric stacks MOS capacitor structure are found to possess better electrical properties than that of HfO2 based MOS capacitors using the PLD deposition technique. 相似文献
5.
Kou-Chen Liu Jung-Ruey Tsai Wen-Kai LinChi-Shiau Li Jyun-Ning Chen 《Thin solid films》2011,519(15):5110-5113
Oxygen plasma treatment process was used to passivate the non-stoichiometric HfO2 films deposited by magnetron sputtering. After optimal oxygen plasma treatment, the gate leakage of HfO2 films would be reduced and dielectric breakdown voltage would be improved to 30 percentage. XPS spectrum was used to analysis the non-stoichiometric HfO2 films after oxygen plasma treatment which demonstrate a higher concentration of incorporated oxygen atoms at the surface in comparison to the bulk HfO2. This simple method can maintain high-k dielectric deposition process at room temperature by sputtering. It would be useful for fabrication thin film transistor on polymer based substrate in the future. 相似文献
6.
Tantalum oxide (Ta
2
O
5
) films and Al/Ta
2
O
5
/Si MOS capacitors were prepared at various powers by ultraviolet photo-inducing hot filament chemical vapour deposition (HFCVD).
Effects of ultraviolet light powers on the structure and electrical properties of Ta
2
O
5
thin films were studied using X-ray diffraction (XRD) and atomic force microscopy (AFM). The dielectric constant, leakage
current density and breakdown electric field of the samples were studied by the capacitance–voltage (C–V) and current–voltage
(I–V) measurements of the Al/Ta
2
O
5
/Si MOS capacitors. Results show that the Ta
2
O
5
thin films grown without inducement of UV light belong to amorphous phase, whereas the samples grown with inducement of UV-light
belong to δ-Ta
2
O
5
phase. The dielectric constant and leakage current density of the Ta
2
O
5
thin films increase with increasing powers of the UV- lamps. Effects of UV- lamp powers on the structural and electrical
properties were discussed. 相似文献
7.
Wen Chiao Chin Kuan Yew Cheong 《Journal of Materials Science: Materials in Electronics》2011,22(12):1816-1826
Samarium oxide (Sm2O3) thin films with thicknesses in the range of 15–30 nm are deposited on n-type silicon (100) substrate via radio frequency
magnetron sputtering. Effects of post-deposition annealing ambient [argon and forming gas (FG) (90% N2 + 10% H2)] and temperatures (500, 600, 700, and 800 °C) on the structural and electrical properties of deposited films are investigated
and reported. X-ray diffraction revealed that all of the annealed samples possessed polycrystalline structure with C-type
cubic phase. Atomic force microscope results indicated root-mean-square surface roughness of the oxide film being annealed
in argon ambient are lower than that of FG annealed samples, but they are comparable at the annealing temperature of 700 °C
(Argon—0.378 nm, FG—0.395 nm). High frequency capacitance–voltage measurements are carried out to determine effective oxide
charge, dielectric constant and semiconductor-oxide interface trap density of the annealed oxide films. Sm2O3 thin films annealed in FG have smaller amount of effective oxide charge and semiconductor-oxide interface trap density than
those oxide films annealed in argon. Current–voltage measurements are conducted to obtain barrier heights of the annealed
oxide films during Fowler–Nordheim tunneling. 相似文献
8.
HfO2 and HfSiO films were prepared on Si substrates by using radio frequency magnetron sputtering (RFMS). Compositional, structural and electronic properties of the two films were investigated completely. X-ray photoelectron spectroscopy (XPS) spectra showed that the atom ratio of Hf to O was about 1:2 in the HfO2 film and the chemical composition of the HfSiO film was Hf37Si7O56. Grazing incidence X-ray diffraction (GI-XRD) patterns indicated crystallization in the HfO2 film after 400 °C annealing, but there is no detectable crystallization in the HfSiO film after 800 °C annealing. C-V measurements indicated that the dielectric constants for the HfO2 and HfSiO film were 20.3 and 17.3, respectively. The fixed charge densities were found to be 6.0 × 1012 cm−2 for the HfO2 film and 3.7 × 1012 cm−2 for the HfSiO film. I-V characteristics showed that the average leakage current densities were 2.4 μA/cm2 for the HfO2 film and 0.2 μA/cm2 for the HfSiO film at the gate bias of 1 V. 相似文献
9.
The chemical structure and electrical properties of HfO2 thin film grown by rf reactive magnetron sputtering after rapid thermal annealing (RTA) were investigated. The chemical composition of HfO2 films and interfacial chemical structure of HfO2/Si in relation to the RTA process were examined by X-ray photoelectron spectroscopy. Hf 4f and O 1s core level spectra suggest that the as-deposited HfO2 film is nonstoichiometric and the peaks shift towards lower binding energy after RTA. The Hf-Si bonds at the HfO2/Si interface can be broken after RTA to form Hf-Si-O bonds. The electrical characteristics of HfO2 films were determined by capacitance-voltage (C-V) and current density-voltage (J-V) measurements. The results showed that the density of fixed charge and leakage current density of HfO2 film were decreased after the RTA process in N2 atmosphere. 相似文献
10.
J. M. Terrazas N. Nedev E. Manolov B. Valdez D. Nesheva M. A. Curiel R. Haasch I. Petrov 《Journal of Materials Science: Materials in Electronics》2010,21(5):481-485
Energy Dispersive X-ray and X-ray Photoelectron (XPS) spectroscopies show that SiO
x
films deposited by reactive r.f. magnetron sputtering at partial pressure ratios R between oxygen and argon in a wide range (1–0.005) have compositions close to the stoichiometric one. For these films high
temperature annealing at 1,000 °C shifts the band in the Fourier Transform-Infrared spectrum due to the Si–O–Si stretching
vibration to values typical of stoichiometric SiO2. Further decrease of R leads to splitting of the Si 2p XPS line indicating increase of the Si content and formation of a
second phase in a SiO2 matrix. The electrical properties of test MOS structures with SiO
x
gate dielectric, regarding defect density in the oxide and at the SiO
x
/c-Si interface, degrade with the decrease of R. High temperature annealing at 1,000 °C strongly improves the properties of
all films regarding leakage current and properties of the interface. 相似文献
11.
Use of germanium as a storage medium combined with a high-k dielectric tunneling oxide is of interest for non-volatile memory applications. The device structure consists of a thin HfO2 tunneling oxide with a Ge layer either in the form of continuous layer or discrete nanocrystals and relatively thicker SiO2 layer functioning as a control oxide. In this work, we studied interface properties and formation kinetics in SiO2/Ge/HfO2(Ge) multilayer structure during deposition and annealing. This material structure was fabricated by magnetron sputtering and studied by depth profiling with XPS and by Raman spectroscopy. It was observed that Ge atoms penetrate into HfO2 layer during the deposition and segregate out with annealing. This is related to the low solubility of Ge in HfO2 which is observed in other oxides as well. Therefore, Ge out diffusion might be an advantage in forming well controlled floating gate on top of HfO2. In addition we observed the Ge oxidation at the interfaces, where HfSiOx formation is also detected. 相似文献
12.
Metal-oxide-semiconductor (MOS) capacitors fabricated by depositing yttrium oxide (Y2O3) using radio frequency sputtering system on top of n-GaAs substrates have been investigated. To study the interface properties, charge trapping behavior and breakdown characteristics of Y2O3 gate dielectric, the MOS capacitors were subjected to constant current stress, high pulse voltage stress and high constant voltage stress. The average value of the cross section of generated traps during electrical stress has been determined from our experimental data. Further the trap charge density, its distribution and location have been investigated by measurements on application and subsequent withdrawal of high pulse voltage stress. Additionally, stress induced leakage current density and time dependent dielectric breakdown characteristics have been obtained and time-to-breakdown exceeding 840 s is observed for Y2O3 gate dielectrics directly deposited on n-GaAs. Our experimental results have been analyzed with simple analytical formulae available in the literature. 相似文献
13.
Shuai Chen Zhengtang Liu Liping Feng Xingsen Che 《Journal of Materials Science: Materials in Electronics》2014,25(2):749-753
The undoped and cerium-doped hafnium oxide (HfO2) thin films have been deposited on p-type single crystal Si(100) substrates using radio frequency magnetron sputtering method. The structure and electrical properties have been investigated as a function of doping concentration. The results show that cerium serves effectively as a dopant to induce the crystallographic change from the monoclinic to the cubic phase. The ceium-doped HfO2 shows higher dielectric constant than undoped HfO2. The dielectric constant enhancement can be explained by the shrinkage of molar volume and the increase of molar polarizability. Compared with undoped HfO2, the cerium-doped HfO2 exhibits a lower leakage current due to the decrease of the oxygen vacancies number. 相似文献
14.
WEN-CHOU TSAI TSEUNG-YUEN TSENG 《Journal of Materials Science: Materials in Electronics》1997,8(5):313-320
A systematic study was performed on the structural and electrical properties of cerium dioxide thin films grown on Si substrate
with various deposition temperatures by RF magnetron sputtering. The films grown at 200°C are partly amorphous whereas those
grown above 250°C are polycrystalline. An amorphous layer of SiO2 forms at the interface between the cerium dioxide film and the Si substrate. Cerium dioxide film grown at higher temperatures
up to 500°C sustains more leakage current on the basis of current-voltage measurements. The electrical conduction of the films
is well fitted by a power-law relation, which is explained as space-charge-limited current conduction with exponential distributed
traps in the band gap. The variations of dielectric constant, flatband voltage, fixed oxide charge and interface-trapped charge
with deposition temperature were studied by making capacitance-voltage measurements on an Al/CeO2/Si structure. The variations of electrical properties with temperature are strongly correlated with the formation of an amorphous
SiO2 layer.
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献
15.
在绝缘材料表面制备半导电性及高导热系数的涂层可以明显提高材料的沿面闪络性能.采用高真空反应磁控溅射方法,在环氧基片表面溅射TiO2、ZrO2,HfO2薄膜,使用快脉冲真空闪络实验装置(50ns/600ns,前沿和半高宽时间),在真空度5×10-3Pa时,研究了上述三种氧化物薄膜的真空闪络特性.实验发现,TiO2和ZrO2薄膜以无定形态存在,表面颗粒未晶化,而HfO2薄膜已经晶化. TiO2薄膜的闪络电压最高,HfO2薄膜较低.TiO2和HfO2随着溅射时间的增加,镀膜的真空闪络电压有所提高,而ZrO2随着溅射时间的增加,镀膜的真空闪络电压有所下降.结合ANSOFT静电场仿真数据,分析了薄膜的基本特性对闪络后表面电位分布及闪络电压的影响机制. 相似文献
16.
S. H. Paek J. H. Won J. E. Jang Y. S. Hwang J. P. Mah J. S. Choi S. T. Ahn J. G. Lee C. S. Park 《Journal of Materials Science》1996,31(16):4357-4362
SrTiO3 thin films were deposited by rf-magnetron sputtering under various sputtering conditions followed by conventional furnace annealing at 600 and 700 °C. The amorphous SrTiO3 thin films crystallized into polycrystals at 600 °C. The leakage current of the SrTiO3 thin films decreased with increasing oxygen partial pressure in the sputtering gas. On the contrary, the dielectric constant increased with increasing the oxygen content in the sputtering gas. The leakage current and dielectric constant increased with increasing substrate temperature and post-annealing temperature. The ratio of SrTi approached 11 with increasing oxygen content in the sputtering gas and substrate temperature during deposition. The oxygen content in the film decreased with increasing the substrate temperature. The capacitance-voltage (C-V) curves showed that the capacitance was nearly independent of the applied voltage. Scanning electron microscopy (SEM) micrographs showed that interdiffusion between the bottom electrode (Pt) and the buffer layer (Ti) occurred during post-annealing, but that the interface between SrTiO3 and Pt was stable. 相似文献
17.
Joel Molina Ana Luz Munoz Wilfrido Calleja Pedro Rosales Alfonso Torres 《Journal of Materials Science》2012,47(5):2248-2255
By using a low cost, simple, and reproducible spin-coating method, thin films of SOG (spin-on-glass)-based oxides with electrical
characteristics resembling those of a dry thermal oxide have been obtained. The superior electrical characteristics of Metal-Oxide-Semiconductor
(MOS) capacitors based on SOG-oxides come from both (1) reducing the organic content of the SOG solutions after dilution with
deionized water and (2) passivation of the silicon surface by a thin chemical oxide. Fourier transform infrared spectroscopy
analysis shows that the organic content in H2O-diluted SOG-oxides is reduced compared to undiluted SOG after N2 annealing. In addition, by chemically embedding HfO2 nanoparticles (np-HfO2) to these SOG-based oxides, an effective increase in the accumulation capacitance of MOS capacitors is observed and this
is related to the increase in the final dielectric constant of the resulting oxide after annealing so that potential use of
SOG as a glass matrix for embedding HfO2 nanoparticles and produce higher-k oxide materials is demonstrated. 相似文献
18.
DONG-WON KIM KAP-JUNG KIM DONG-IL KIM WON-JUN LEE SEUNG-YUN LEE YOUNG J LEE SA-KYUN RHA CHONG-OOK PARK 《Journal of Materials Science: Materials in Electronics》1997,8(2):91-94
Capacitors with two kinds of lower electrodes were fabricated and their effects evaluated on the electrical characteristics
of oxide–nitride–oxide (ONO) film. One of the electrodes was made of amorphous silicon film chemically deposited using a gas
mixture of Si2H6–PH3; the other was made of poly-Si film deposited by SiH4 decomposition and doped by As+ ion implantation.
The ONO thin dielectric layer was composed of natural oxide, CVD silicon nitride and thermal oxide formed on the silicon nitride.
The capacitance, the leakage current, the dielectric breakdown field and the time-dependent dielectric breakdown (TDDB) were
tested to evaluate the electrical properties of the capacitors. The leakage current and the dielectric breakdown voltage showed
similar values between the two capacitors, whereas the TDDB under negative bias showed a great difference. This indicates
that, with respect to electrical properties, the integrity of the oxide grown on the in situ P-doped amorphous silicon is
better than the oxide grown on the As+ ion-implanted poly-Si. What is more, phosphorus in the amorphous silicon did not lead
to any problems with junction depth, even after post heat treatment at 950°C.
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献
19.
Wen Feng Qin Wan Yong Ai Jun Zhu Jie Xiong Jinlong Tang Ying Zhang Yan Rong Li 《Journal of Materials Science》2007,42(20):8707-8713
Conductive SrRuO3 (SRO) thin films have been grown on (100) MgO substrates by pulsed laser deposition (PLD) technique. Effects of oxygen pressure
and deposition temperature on the orientation of SRO thin film were investigated. X-ray diffraction (XRD) θ/2θ patterns and
the temperature dependent resistivity measurements indicated that oxygen pressure of 30 Pa and deposition temperature of 700 °C
were the optimized deposition parameters. A parallel-plate capacitor structure was prepared with the SRO films deposited under
optimized condition as an electrode layer and Ba0.60Sr0.40TiO3 (BST) thin film as the dielectric layer. XRD Φ scans indicated a
epitaxial relationship between BST and SRO on MgO substrate. The dielectric constant and loss tangent measured at 10 kHz
and 300 K was 427 and 0.099 under 0 V bias, and 215 and 0.062 under 8 V bias, respectively. A tunability of 49.6% has been
achieved with DC bias as low as 8 V. The C–V hysteresis curve and the P–E hysteresis loop suggested that the BST films epitaxially grown on SRO/MgO have ferroelectricity at room temperature. The
induced ferroelectricity was believed to originate from the compressive strain between the epitaxial BST and SRO thin films.
These results show the potential application of the BST/SRO heterostructures in microelectronic devices. 相似文献
20.
Metal oxide semiconductor (MOS) capacitors with titanium oxide (TiOx) dielectric layer, deposited with different oxygen partial pressure (30, 35 and 40%) and annealed at 550, 750 and 1000 °C, were fabricated and characterized.Capacitance-voltage and current-voltage measurements were utilized to obtain, the effective dielectric constant, effective oxide thickness, leakage current density and interface quality. The obtained TiOx films present a dielectric constant varying from 40 to 170 and a leakage current density, for a gate voltage of − 1 V, as low as 1 nA/cm2 for some of the structures, acceptable for MOS fabrication, indicating that this material is a viable high dielectric constant substitute for current ultra thin dielectric layers. 相似文献