bluuebunny/crossref_metadata_2025_split huggingface dataset:
The Role of Hydrogen in Semi-Insulating Inp
Authors: Han Yujie , Liu Xunlang , Jiao Jinghua , Qian Jiajun , Chen Yonghai , Wang Zhanguo , Lin Lanying 
Published: April 2011

ABSTRACTComplexes of vacancy at indium site with one to four hydrogen atoms and isolated hydrogen or hydrogen dimer and other infrared absorption lines, tentatively be assigned to hydrogen related defects were investigated by FTIR. Hydrogen can passivate imperfections, thereby eliminating detrimental electronic states from the energy bandgap.Incorporated hydrogen can introduce extended defects and generate electrically-active defects. Hydrogen also can acts as an actuator for creating of antistructure defects. Isolated hydrogen related defects(e.g. H12+) may play an important role in the conversion of the annealed wafers from semiconducting to the semi-insulating behavior. H2+ may be a deep donor, whose energy level is very near the iron deep acceptor level in the energy gap.
Hydrogen Passivation of Be-Acceptors in AiGaAs/GaAs Quantum Well Structures
Authors: Zhaoa Q. X. , Södervall U. , Willandera M. , Fimland B. O. , Crawford D. , Selvigb E. , Holtzc P. O. , Karlsteena M. , Sveinbjömssond E. 
Published: April 2011

ABSTRACTHigh quality Al0.3Ga0.7As/GaAs quantum wells with centrally doped Be-acceptors were grown by molecular beam epitaxy (MBE). The well width is either 10 nm or 20 nm, and the concentration of Be-acceptors is varied between 5× 1016/cm3 and 2×1018/cm3. The structures were treated systematically by dc H-plasma at different sample temperatures, gas pressures and cooling down procedures. The passivation of Be-acceptors were characterized by photoluminescence spectroscopy and secondary ion mass spectrometry (SIMS). Without causing degradation of the A1GaAs/GaAs interfaces, we have obtained, for the first time, a deactivation of above 80% of the Be-acceptors. The influence of the Be-doping on the bandgap excitons in the QW structures is also investigated in detail. A significant difference is found in comparison with the earlier reports for 150 Å wide quantum wells, in which different samples were used for different doping concentrations.
Interaction of Atomic Hydrogen with the Surface of Cu-llII-V12 Chalcopyrite Semiconductors-A Method for Controlled Stoichiometry Variation
Authors: Lippold Gerd , Otte Karsten , Schlemm Hermann , Grill Wolfgang 
Published: April 2011

ABSTRACTTo introduce atomic hydrogen into Cu-chalcopyrite samples, low energy broad beam ion implantation into heated targets was used. In addition to the expected hydrogen diffusion into the sample from the implanted thin surface layer, another hydrogen-related effect was observed. As demonstrated for single crystalline CuInSe2, at target temperatures above 150°C a surface layer becomes In-rich. Two phases, the CuInSe2 α-phase and a In-rich phase similar to the reported ordered vacancy compounds (β-phase) coexist, as detected by Raman spectroscopy. The depth profile and the thermal stability of this hydrogen-related compositional variation are investigated. Based on the results we discuss a model of this effect, involving a copper in-diffusion, caused by the hydrogenation due to filling of Cu vacancies and possible substitution of Cu by H. The observed β-phase-like compound is unstable against annealing above 180°C, but can be restored in a thermal cycling process. Annealing for 1.5 h at 400°C removes it completely and restores the asgrown CuInSe2 surface. A decrease of the hydrogen concentration in the surface layer due to redistribution and out-diffusion, followed by the recovery of the Cu content, might be responsible for this behaviour.
The Contribution of H Ion Etching Under Different Substrate Bias to the Orientation Degree of Diamond Films
Authors: Zhang W. J. , Jiang X. 
Published: April 2011

ABSTRACTAn etching process of hydrogen ions was performed during the initial growth stage of diamond films. The H+ ion etching was performed by applying a negative substrate bias during a microwave plasma chemical vapor deposition process, using only hydrogen as a reactant gas. The contribution of H+ etching under different substrate bias and for different etching time to the orientation degree of diamond films was investigated by scanning electron microscopy and atomic force microscopy. It was found that an additional H+ etching process had influence on the orientation degree of deposited (001)-oriented diamond films. To achieve a significant improvement of crystal orientation, the bias voltage and etching time should be adjusted concerning to the situation of diamond films.
Thermal Desorption of Hydrogen in Si and Sic Nanoparticles Produced by Plasma-Enhanced Chemical-Vapor Deposition
Authors: Costa J. , Fort J. , Suñol J. J. , Roura P. , Viera G. , Bertran E. 
Published: April 2011

ABSTRACTMass spectrometry and calorimetry experiments on hydrogen evolution in amorphous Si:H and SiC:H nanoparticles grown by Plasma-Enhanced Chemical-Vapor Deposition (PECVD) are reported. The evolution spectra in a-Si particles are very similar to those found in films. The dynamic constants of the low-temperature peak confirm that this process is the same as in films. It is argued that the high-temperature process may not be diffusion-controlled. Both processes are exothermic, indicating that most dangling bonds recombine after H-desorption. The Hevolution in SiC occurs at higher temperatures than in Si. The process is endothermic.
Dissociation of Deuterium-Defect Complexes in Ion-Implanted Epitaxial 4H-SiC
Authors: Janson M. , Linnarsson M. K. , Hallén A. , Svensson B. G. 
Published: April 2011

ABSTRACTEpitaxial layers of low doped 4H-SiC are implanted with 20 keV 2H+ ions to a dose of 1×1015 cm−2. The samples are subsequently annealed at temperatures ranging from 1040 to 1135 °C. Secondary ion mass spectrometry is used to obtain the concentration versus depth profiles of the atomic deuterium in the samples. It is found that the concentration of implanted deuterium decreases rapidly in the samples as a function of anneal time.The experimental data are explained by a model where the deuterium migrates rapidly and becomes trapped and de-trapped at implantation-induced defects which exhibit a slightly shallower depth distribution than the implanted deuterium ions. Computer simulations using this model, in which the damage profile is taken from Monte Carlo simulations and the surface is treated as a perfect sink for the diffusing deuterium atoms, are performed with good results compared to the experimental data. The complexes are tentatively identified as carbon-deuterium at a Si-vacancy and a dissociation energy (ED) of approximately 4.9 eV is extracted for the deuterium-vacancy complexes.
The Effect of Hydrogen/ Deuterium Introduction on Photoluminescence of 3C-SiC Crystals
Authors: Lee B. K. , Steckl A. J. , Zavada J. M. , Wilson R. G. 
Published: April 2011

ABSTRACTThe effect of the incorporation and annealing of deuterium in 3C-SiC on its photoluninescence is reported. A 3C-SiC crystal has been implanted with 100 keV deuterium and subsequently annealed at temperatures between 1015 °C and 1220 °C for 1 to 5 minutes. SIMS depth profiles indicate hydrogen is strongly trapped by defects generated through ion bombardment, but a gradual damage repairing occurs during annealing. Photoluminescence was measured with 488 nm Ar laser excitation for sample temperatures from 89 K to 400 K. The PL peak wavelength of 540 nm at room temperature has shifted to 538 nm at 89 K. The peak PL intensity decreases with measurement temperature while its full width at half maximum (FWHM) exhibits an increasing trend. PL data were taken at five annealing stages. The post-implantation peak PL intensity and its integrated area increase initially with annealing temperature and time. After the final annealing at 1218 °C for 2 minute, PL intensity and its integrated area exhibit a decrease in level.
Silicide Technology in Deep Submicron Regime
Authors: Suguro K , Iinuma T. , Ohuchi K , Miyashita K. , Akutsu H. , Yoshimura H. , Akasaka Y. , Nakajima K , Miyano K , Toyoshima Y. 
Published: April 2011

ABSTRACTSilicide technology using cobalt-titanium alloy has been developed for sub-quarter micron devices. Extremely flat and epitaxial CoSi2 films are successfully grown on a (100) Si substrate. Improved SALICIDE process is not influenced by native oxide on a Si surface. This technology will be very useful in deep sub-quarter micron devices.
Formation and Thermal Stability of Nd0.32Y0.68Si1.7 Layers Formed by Channeled Ion Beam Synthesis
Authors: Wu M. F. , Vantomne A. , Hogg S. , Pattyn H. , Langouche G. , Jin S. , Bender H. 
Published: April 2011

ABSTRACTThe Nd-disilicide, which exists only in a tetragonal or an orthorhombic structure, cannot be grown epitaxially on a Si(111) substrate. However, by adding Y and using channeled ion beam synthesis, hexagonal Nd0.32Y0.68Si1.7 epilayers with lattice constant of aepi = 0.3915 nm and cepi = 0.4152 nm and with good crystalline quality (χmin of Nd and Y is 3.5% and 4.3 % respectively) are formed in a Si(111) substrate. This shows that the addition of Y to the Nd-Si system forces the latter into a hexagonal structure. The epilayer is stable up to 950 °C; annealing at 1000 °C results in partial transformation into other phases. The formation, the structure and the thermal stability of this ternary silicide have been studied using Rutherford backscattering/channeling, x-ray diffraction and transmission electron microscopy.
C49-TiSi2 Epitaxial Orientation Dependence of the C49-to-C54 Phase Transformation Rate
Authors: Nakamura T. , Ikeda K. , Tomita H. , Komiya S. , Nakajima K. 
Published: April 2011

ABSTRACTEffects of the C49-TiSi2 epitaxial orientation on the C49-to-C54 phase transformation rate have been studied for samples with different pre-amorphization implantation (PAI) conditions. The C49 epitaxial orientation to the Si(001) substrate is characterized by use of grazing-incidence X-ray diffraction (GIXD) measurements. We found that the PAl treatment suppresses the epitaxial growth of C49-TiSi2 on Si(001) substrates and the poorer orientational alignment of C49-TiSi2 causes a more rapid transformation to C54-TiSi2. We believe this suppression of epitaxial alignment is a possible mechanism to understand the effect of the PAl treatment on the C49-C54 transformation.
Selective Rapid Thermal Chemical Vapor Deposition of Titanium Silicide on Arsenic Implanted Silicon
Authors: Fang Hua , Özttirk Mehmet C. , Seebauer Edmund G. 
Published: April 2011

ABSTRACTThis work explores the effects of arsenic on rapid thermal chemical vapor deposition (RTCVD) of TiSi2. The films were deposited using TiCI4 and SiH4 on 100 mm oxide patterned silicon wafers selectively at temperatures ranging from 750°C to 850°C. Arsenic dose levels ranging from 3×1014 cm−2 to 5*times;1015 cm−2 at 50 keV were considered. Experimental results reveal that arsenic results in a resistance to TiSi2 nucleation and enhanced silicon substrate consumption. These effects are enhanced at higher arsenic dose levels and reduced at higher deposition temperatures. We propose an arsenic-surfacepassivation model to explain the effects.
Process Design & Integration of Salicide and Source/Drain process Modules for Improved Device Performance
Authors: Apte Pushkar P. , Saxena Shared , Rao Suraj , Vasanth Karthik , Prinslow Douglas A. , Kittl Jorge A. , Breedijk Terence , Pollack Gordon 
Published: April 2011

ABSTRACTTo enable swift integration of process modules into manufacturable process flows; three components – individual process modules, their interactions and their variability-must be understood well. At dimensions ≤ 0.25 μm, this understanding is especially critical, and also quite challenging. We present here an approach to address this challenge by joint process design, using two key modules-salicide and source/drain-as an example. Together, these modules impact the silicide-to-diffusion contact resistance, (Rc), and the gate sheet resistance (Rs); which, in turn, significantly affect transistor series resistance and circuit delays respectively. We have built a model to help provide insight into the underlying physical mechanisms, and to help provide a quantitative framework for optimizing performance and variability. Rc, depends critically on the doping concentration immediately adjacent to the silicide, and this concentration is determined by the combined effect of silicide processing and the two-dimensional source/drain dopant profile. Rs depends on the thickness and phase of the silicide film formed, which, in turn, depend on the salicide process variables as well as the source/drain doping concentration, because both affect the silicide growth kinetics. Process conditions favoring Rs. and Rc are opposite to each other: thicker silicide films and higher thermal budgets help in the phase-transformation to the low-resistivity C54 phase and improve Rs but they increase dopant redistribution and worsen Rc. Optimal process design can improve the transistor drive current (Id) by ≈5%, and circuit performance, as measured by the figure-of-merit (FOM) by ≈ 4%. This improvement is significant, and an added benefit of this approach is that other transistor characteristics such as effective channel length, off-current, substrate current, etc. remain unchanged. In summary, we have demonstrated that by joint process design and integration of the salicide and source/drain modules, insight can be gained into the underlying physical mechanisms, and device and circuit performance can be improved significantly.
A Study of Transistor Optimization in A 0.25 Micron CMOS Flow Using S/D and Silicide Process Modules and Their Interactions
Authors: Vasanth K. , Apte P. , Davis J. , Saxena S. , Burch R. , Rao S. , Mozumder P. K. 
Published: April 2011

ABSTRACTA modular approach to CMOS process development requires an understanding of individual process modules (channel, gate, etc.) and their interactions. The reverse short channel effect, (RSCE) in NMOS devices is one such interaction between the channel and source/drain (S/D) modules. Similarly the interaction between the S/D and silicide modules affects the contact and gate sheet resistance. This paper presents (a) an investigation of the effects of S/D processing (As and P implant conditions) on the RSCE, (b) effects of S/D and silicide processing on the contact and gate sheet resistance, (c) the use of an integrated system to optimize process modules and their interactions and (d) the validity of the modules and system in process development by obtaining a 4% improvement in drive current of a 0.25 micron NMOS device. The outputs of the S/D module include the doping profiles as a function of implant and anneal conditions. The interaction between the channel and S/D is caused by the damage created during the S/D implants, leading to channel dopant redistribution during subsequent thermal anneals. This interaction causes the RSCE in NMOS devices and has to be taken into account before the modules can be used for process optimization. The interaction is studied by varying the dose and energy of the As and P S/D implants and observing their effect of the RSCE. Further, to model this interaction, parameters of a 2D dopant profile model are extracted from device data and form a part of the S/D module in addition to the doping profile information. The system integrates the outputs from the process modules and their interactions and allows for a rapid search of the process space. The search criteria can be varied to include performance (e.g. drive and off current) and manufacturability criteria.
Properties of Cu3Ge Films for Contacts to Si and SiGe and Cu Metallization
Authors: Borek Mark A. , Oktyabrsky S. , Aboelfotoh M. O. , Narayan J. 
Published: April 2011

ABSTRACTWe have formed thin films of Cu3Ge on (100) Si and (100) Si50Ge50 for low resistivity ohmic contacts and interconnects by the sequential room temperature e-beam deposition of a layer of amorphous Ge, followed by a polycrystalline layer of Cu. We have also deposited thin films of Cu on the Si50Ge50 to compare the behavior of films of Cu3Ge relative to that of pure Cu. We have determined by transmission electron microscopy (TEM) that films of Cu3Ge form an abrupt interface with Si and Si50Ge50, with no indication of interaction between the film and substrate. We have also shown by secondary ion mass spectrometry (SIMS) that Cu diffusion into the underlying substrate is not observed for films of Cu3Ge as compared to that of pure Cu. We have shown that Cu reacts with Si50Ge50 when annealed or 30 min. at 400°C to form a layer of Cu3Si1−xGe.. We have also observed that room temperature oxidation of the underlying Si50Ge50 does not occur as compared to the room temperature formation of SiO2 that is observed in Cu3Si/Si structures.
Multilevel Interconnection Technologies and Future Requirements for Logic Applications
Authors: Brillouët M. 
Published: April 2011

ABSTRACTThe performance and cost of the logic ICs is more and more dominated by the interconnections. Reducing the capacitances in the advanced processes, especially with low k dielectrics, is a priority, while a differentiated approach can be applied for lowering the connection resistances, e.g. in adapting the interconnect material to specific levels. Integrating new materials leads to difficult trade-offs in order to achieve a good electrical performance of the circuit. Finally the increased number of levels of interconnection addresses other fields like integration density, defectivity reduction or cost.
The Effect of Impurities in Tin Film When Used As Mos Gate Electrodes
Authors: Yag H. , Hu J. C. , Lu J. P. , Brown G. A. , Rotondara A. L. P. , Luttmer J. D. , Magel L. K. , Liu H.-Y. , Chen P. J. 
Published: April 2011

ABSTRACTRefractory metal gates have been studied for CMOS gate electrodes on ultra thin gate oxide due to its midgap work function, low resistivity and no gate depletion, etc. In particular, titanium nitride received most attention because of its process maturity and its good diffusion barrier properties for backend applications. Different TiN film properties are important when TiN is used as a gate material than when it is used for backend applications. One issue is the effect of TiN film impurities on the gate oxides and their high temperature stability since some high temperature processes are usually needed after gate formation. This paper reports the study of different TiN films used as MOS gate electrodes on ultra thin gate oxide and the effects of their impurities on gate oxide electrical performance. PVD TiN films deposited with different process conditions show different oxygen content, and different gate oxide properties were observed when these PVD TiN films were used as gate electrodes. On the other hand CVD TiN films deposited using different precursors also showed different impurities, including carbon, oxygen or silicon, which largely affect CVD TiN performance when used as gate material. The different TiN films were characterized by X-ray glancing angle reflection, XPS, SIMS and TEM, and the electrical properties were studied by I-V, C-V, charge to breakdown (Qbd) and ramp voltage breakdown tests on MOS capacitors. The results showed that the high purity TiN films provide stable gate material with small damage to the gate oxide, but impurities, especially oxygen, affect the gate oxide properties after high temperature anneal. However, due to the different TiN process capabilities, TiN films with impurities may still have advantages over pure TiN film in some cases of different MOS gate applications.
A Main Factor Determining the Uniform Step Coverage in Chemical Vapor Deposition
Authors: Shin Chee Burm , Hwang Gyeong Soon 
Published: April 2011

ABSTRACTProfile evolution simulations during chemical vapor deposition based on a 2-D continuum model reveal that the type of surface kinetics plays an important role as a measure of determining step coverage of films deposited in a high aspect ratio trench or via. The linear surface kinetics, resulting from adsorption rate limitation, is found to be difficult to bring about conformal step coverage in a deep narrow trench without reducing the growth rate considerably; that is, under such a condition void free filling can not be achievable with holding an appropriate growth rate. High tendency of the precursor for chemical equilibrium on a surface, tending to cause the non-linear surface kinetics by surface reaction limitation, is mainly responsible for the significant improvement of step coverage in TEOS-based depositions.
Characterization of Thin Titanium and Titanium Nitride Layers Using Sims
Authors: Li-Fatou Andrei V. , Sardela Mauro R. , Tian Chunsheng 
Published: April 2011

ABSTRACTTitanium (Ti) and titanium nitride (TiN) films are widely used as barrier stack to prevent junction spiking. It is also an important material for an anti-reflection coating (ARC) on aluminum (Al) films to facilitate lithography processes during multilevel metallization for the manufacture of integrated circuits on silicon-based (Si) semiconductor devices. Secondary Ion Mass Spectrometry (SIMS) is proven to be very powerful analytical technique for the semiconductor materials. However, quantitative analysis of very thin structures using SIMS constitutes an ultimate challenge since a large fraction of the profile is located in the transient region where a stable concentration of primary beam species has not been established.This paper reports a SIMS technique for advanced characterization of very thin titanium and titanium nitride layers. Improvements in depth resolution were achieved by reducing the angle of incidence and the impact energy maintaining enhanced ionization yield associated with oxygen bombardment. Significant improvements in characterization of the film surface were developed by using oxygen flooding technique. Optimized oxygen pressure was used to achieve a stable ion yield due to the complete surface oxidation of titanium and titanium nitride layers during the analysis. The method was employed in the SIMS characterization of multiple Ti/TiN films deposited on silicon substrate. The example presents dramatic enhancement in depth resolution due to minimized matrix related ion yield variations at the interfaces.