Ge／Pd／n—GaAs低阻欧姆接触的SIMS分析

采用Ｇｅ／Ｐｄ／ＧａＡｓ结构和快速热退火在ｎ－ＧａＡｓ上形成了低阻欧姆接触，利用二次离子质谱技术揭示和讨论了低欧姆接触形成的机理。比较了采用Ｘ＾＋和ＧｓＸ＾＋信号检测的Ｇｅ，Ｐｄ，Ｇａ和Ａｓ的深度分布。结果表明采用ＣｓＸ＾＋可以提供更准确的结果和成分信息。     

Au/Ti/W/Ti与n-GaAs欧姆接触的特性研究

用磁控溅射系统和快速合金化法制备了Au/Ti/W/Ti多层金属和n-GaAs材料的欧姆接触,用传输线法对其比接触电阻进行了测试,并利用俄歇电子能谱(AES)和X射线衍射图谱(XRD)对接触的微观结构进行了研究。结果表明该接触在700℃时比接触电阻为1.5×10~(-4)Ω·cm~2,快速合金化后呈现欧姆特性可能与接触界面处生成的TiAs相有关。     

Ge/Pd/n-GaAs低阻欧姆接触的SIMS分析

采用Ge／Pd／GaAs结构和快速热退火在n－GaAs上形成了低阻欧姆接触。利用H次离子质谱（SIMS）技术揭示和讨论了低欧姆接触形成的机理。比较了采用X 和CsX 信号检测的Ge，Pd，Ga和As的深度分布。结果表明采用CSX 可以提供更准确的结果和成分信息。     

AuGeNi—n型GaAs欧姆接触界面微区结构与接触电阻率的关系

欧姆接触是砷化镓器件中的基本单元，它的电性能极大地影响器件的质量。在众多的欧姆接触系统中，ＡｕＧｅＮｉ系统应用最为广泛。利用扫描俄歇电子微探针对离子注入重掺杂的ｎ型ＧａＡｓ上利用快速热合金制备的ＡｕＧｅＮｉ欧姆接触进行了研究，比较了不同退火温度下欧姆接触的电性能和微区界面结构，对界面微区结构与接触电阻的关系进行了探讨，提出了产生低阻接触的理想微区结构，为工艺参数的选择提供了有益的依据。     

Ti／AlN快速退火界面反应的实验研究

在电子封装用的ＡｌＮ陶瓷多晶衬底上生长２５０ｎｍ的Ｔｉ膜，并进行快速退火。用ＲＢＳ（卢瑟福背散剂）、ＡＥＳ（俄歇有谱）、ＳＩＭＳ（干净人离子质谱）ＸＲＤ（Ｘ射线衍射）等实验技术对界面反应进行了分析研究，用划痕实验测量了退火对Ｔｉ／ＡｌＮ粘附力的影响。实验结果表明：快速退火时，Ｔｉ，Ａｌ，Ｎ以及ＡｌＮ中掺杂的Ｏ均发生明显的界面扩散和界面反应，样品表面的Ｏ和ＡｌＮ衬底中掺杂的Ｏ都向Ｔｉ膜中扩散，在较低     

Si基n型GaN的欧姆接触研究

GaN材料在光电子器件领域的广泛应用前景使得金属与其欧姆接触的研究成为必然。本文对Si基n型GaN上的Al单层及Ti/Al双层电极进行了研究。通过对不同退火条件下的I U特性曲线 ,X射线衍射以及二次离子质谱分析 ,揭示了界面固相反应对欧姆接触的影响 ,提出了改善这两种电极欧姆接触的二次退火方法     

Ti/A1N快速退火界面反应的实验研究

在电子封装用的A1N陶瓷多晶衬底上生长250nm的Ti膜，并进行快速退火。用RBS（卢瑟福背散射）、AES（俄歇电子能谱）、SIMS（二次离子质谱）和XRD（X射线衍射）等实验技术对界面反应进行了分析研究，用划痕实验测量了退火对Ti／A1N界面粘附力的影响。实验结果表明：快速退火时，Ti，A1，N以及A1N中掺杂的O均发生明显的界面扩散和界面反应。样品表面的O和A1N衬底中掺杂的O都向Ti膜中扩散，在较低的退火温度下生成TiO2；在较高的退火温度下与扩散到Ti膜中的A1反应，在Ti膜中间形成Al2O3层。N向Ti中扩散，并与Ti反应生成TiN。在薄膜和衬底之间有Ti的氧化物生成。粘附力的测量结果表明：在较低的温度下进行快速退火可以明显提高Ti／A1N界面的强度，在较高的温度下，界面强度有所下降。     

Si基n型GaN的欧姆接触研究

GaN材料在光电子器件领域的广泛应用前景使得金属与其欧姆接触的研究成为必然。本对Si基n型GaN上的A1单层及Ti/Al双层电极进行了研究。通过对不同退火条件下的I—U特性曲线，X射线衍射以及二次离子质谱分析，揭示了界面固相反应对欧姆接触的影响，提出了改善这两种电极欧姆接触的二次退火方法。     

Effect of heating on the behaviors of hydrogen in C-TiC films with auger electron spectroscopy and secondary ion mass spectroscopy analyses

C-TiC films with a content of 75% TiC were prepared with magnetron sputtering deposition followed by Ar⁺ ion bombardment. Effect of heating on the behaviors of hydrogen in C-TiC films before and after heating was studied with Auger Electron Spectroscopy and Secondary Ion Mass Spectroscopy (SIMS) analyses. SIMS depth profiles of hydrogen after H⁺ ion implantation and thermal treatment show different hydrogen concentrations in C-TiC coatings and stainless steel. SIMS measurements show the existence of TiH, TiH₂, CH₃, CH₄, C₂H₂ bonds in the films after H⁺ ion irradiation and the changes in the Ti LMM, Ti LMV and C KLL Auger line shape reveal that they have a good hydrogen retention ability after heating up to the temperature 393 K. All the results show that C-TiC coatings can be used as a hydrogen retainer or hydrogen permeable barrier on stainless steel to protect it from hydrogen brittleness.     

Improved microstructure and ohmic contact of Nb electrode on n-type 4H-SiC

Niobium was deposited as an electrode material on an n-type SiC wafer for power device application. The reaction microstructure and electrical contact property were investigated after annealing at 700 to 1000 °C and compared with the results for an Ni electrode. Microstructure-related problems of the Ni electrode could be resolved without sacrificing ohmic contact behavior with a low contact resistivity of 1.53 × 10^− 4 Ω cm². Carbon precipitation was completely eliminated with Nb by the formation of carbides, leading to good adhesion upon wire bonding process. At the reaction interface, Nb₅Si₃ was formed in an epitaxial relationship with SiC, leading to a good interface contact property as well as good interface adhesion.     

光阴极材料GaAs/AlGaAs的组分分析

为探索砷化镓光阴极的光电灵敏度的影响因素 ,利用X射线光电子能谱、二次离子质谱和电化学方法测试和分析了国内和国外GaAs光阴极材料GaAs/AlGaAs的C ,O含量和空穴浓度分布。实验发现 ,国内的材料在GaAs/AlGaAs界面及AlGaAs层的O含量分别为 7 6 %和 10 6 % ,C浓度分别为 5 2×10 18atoms/cm3和 1 0× 10 19atoms/cm3,而国外的材料的O含量相应为 1 0 %和 1 5%。国内的材料GaAs和AlGaAs层的空穴浓度分别为 7× 10 18～ 4× 10 19cm- 3和 8× 10 17cm- 3,而国外材料的相应值分别为 (1 8～ 2 0 )× 10 19cm- 3和 5× 10 18cm- 3。分析认为 ,层中及界面的C ,O杂质偏高和空穴浓度分布不尽合理使光电子扩散长度减小 ,后界面复合增大 ,导致了光电灵敏度下降。     

Evaluation of the depth resolutions of Auger electron spectroscopic, X-ray photoelectron spectroscopic and time-of-flight secondary-ion mass spectrometric sputter depth profiling techniques

Concentration-depth profiles of sputter-deposited Si/Al multilayered specimens were determined by model fitting to measured data obtained by depth profiling, using Auger electron spectroscopy (AES), X-ray photoelectron spectroscopy (XPS) and time-of-flight secondary-ion mass spectrometry (TOF-SIMS). The model used for calculation of the concentration-depth profile accounts for the broadening (“smearing”) upon experimental depth profiling owing to the effects of atomic mixing, preferential sputtering, surface roughness and information depth of either the Auger electrons (for AES depth profiling) or the photoelectrons (for XPS depth profiling) or the secondary ions (for SIMS depth profiling). The depth resolution for each technique was derived directly from the values determined for the fitting parameters in the model.     

Comparative Study of LiMn2O4 Thin Films Heat-treated by Conventional and Rapid Thermal Annealing

Cathode material LiMn2O4 thin films were prepared by solution deposition followed by conventional thermal annealing (CTA) and rapid thermal annealing (RTA) using lithium acetate and manganese acetate as starting materials. The phase and surface morphology identification was done by X-ray diffraction and scanning electron microscopy. The electrochemical properties of the thin films were carried out by cyclic voltammetry, charge-discharge experiments, electrochemical impedance spectroscopy and potential step technique. The results show that both thin films are homogeneous and crack-free. Compared with the CTA derived thin films, the RTA derived ones with smaller grain size are more smooth and dense. The CTA and RTA derived LiMn2O4 thin films deliver the capacity of 34.5 μAh/(cm2 ·μm) and 38 μAh/(cm2 ·μm) and show the capacity loss of 0.050% and 0.037% per cycle after being cycled 100 times, respectively. The diffusion coefficient of lithium ion in the CTA derived LiMn2O4 thin-film electrode is 4.59×10-11 cm2/s, and that of lithium ion in the RTA derived one is 3.86×10-11 cm2/s.     

Secondary ion emission from Ti and Si targets induced by medium energy Ar ion bombardment - Experiment and computer simulation

The paper presents experimental results of secondary ion energy distributions obtained for Ti and Si targets bombarded by 20-30 keV monoisotope Ar⁺ ion beam. The influence of the extraction voltages between target and a slit of the electrostatic energy analyzer entrance on the energy distributions of secondary ions was investigated. After optimization of the secondary ion extraction system, the mass spectra of secondary ions were also measured. The investigations were done using recently built experimental system. Experimental data are compared with the computer simulation results obtained using TRQR and SATVAL codes.     

The characteristics of fluorinated polycrystalline silicon oxides and thin film transistors by CF4 plasma treatment

This study describes a simple fluorinating technique by the tetrafluoromethane (CF₄) plasma treatment to form fluorinated polyoxides and polycrystalline silicon thin film transistors (TFTs). In comparison with the non-fluorinated device, the fluorinated polyoxides and devices exhibit a higher breakdown field (>8 MV/cm), low charge trapping rates, low off-state current, and low trap states. Furthermore, the performance and reliability of the fluorinated devices are also improved by the CF₄ plasma treatment. This is due to the fact that the incorporated fluorine can break strain bonds to form stronger silicon-fluorine (Si-F) bonds to passivate the generation of interface and trap states existing near the polyoxide/polysilicon interface and grain boundaries.     

Improvement of the properties and electrical performance on TiCl4-based TiN film using sequential flow chemical vapor deposition process

Sequential flow chemical vapor deposition (SFCVD), utilizing TiCl₄/NH₃ as reactants and immediate NH₃ treatment after film deposition, is applied to produce TiN barrier films in the contact process. Secondary ion mass spectroscopy results indicate that the SFCVD TiN film can effectively block the diffusion of WF₆ into the underlying Ti layer during W deposition. NH₃ treatment immediately after film deposition causes SFCVD TiN films to be less contaminated with carbon than TiN films that are formed by metallic organic compounds chemical vapor deposition (MOCVD) and to contain less chlorine residue than conventional TiCl₄/NH₃ CVD TiN layers even at a low reaction temperature. According to the resistance measurement of Kelvin contacts, the SFCVD process yields a lower resistance and a more uniform distribution than the MOCVD or CVD process. Transmission electron microscopic observations demonstrate that WF₆ can diffuse through the MOCVD TiN to react with the underlying Ti layer, causing a rupture at the Ti/TiN interface and poor W adhesion. The SFCVD TiN can serve as a sufficient diffusion barrier against WF₆ penetration during W CVD deposition.