MBE外延InSb基CdTe工艺研究

成功制备了CdTe/InSb复合衬底,为长波HgCdTe外延提供了可能。通过工艺研究解决了InSb氧化层去除及In元素扩散控制两个难点问题,使用As钝化法可以解决双腔衬底转移的问题,在常用的退火工艺下,通过厚度的调整可以阻挡In元素的扩散。     

Influence of the dissolution of MnS inclusions under free corrosion and potentiostatic conditions on the composition of passive films and the electrochemical behaviour of stainless steels

The influence of the dissolution of MnS inclusions at the OCP value and 400 mV versus SCE on the chemical composition of passive films and the electrochemical behaviour of resulfurized austenitic stainless steel was studied in 1 M NaClO₄, pH 3, solution using SIMS, XPS, electrochemical impedance spectroscopy and the electrochemical microcell technique. The electrochemical dissolution (at 400 mV versus SCE) of inclusions occurred uniformly along the interface and this process was almost complete after 25 min immersion. A small amount of sulfur was detected on the matrix that exhibited a wide passive range. By contrast, the dissolution process under free corrosion was not uniform along the interface and numerous inclusions were partly dissolved. Grains close to the completely dissolved inclusions showed an active behaviour. This was connected with the adsorption of a large number of sulfur on the surface. In the two cases, the presence of sulfur species on the surface was also found to enhance the kinetics of cathodic reactions.     

Signal standardization of the secondary ion mass spectrometry (SIMS) microscope for quantification of halogens and calcium in biological applications

The secondary ion mass spectrometry (SIMS) microscope is able to map chemical elements in tissue sections. Although absolute quantification of an element remains difficult, a relative quantitative approach is possible for soft tissue by using carbon (¹²C) as an internal reference present at large homogeneous and constant concentration in specimen and embedding resin. In this study, this approach is used to standardize the signal of an SIMS microscope for the quantification of halogens (¹⁹F^—, ³⁵Cl^— and ⁷⁹Br^—) and calcium (⁴⁰Ca⁺). Standard preparation was determined based on homogeneity and stability criteria by molecular incorporation (halogens) or mixing (calcium) in methacrylate resin. Standard measurements were performed by depth analysis on areas of 8 μm (halogens) and 150 μm (calcium) in diameter for 10–30 min, under Cs⁺ (halogens) or O₂⁺ (calcium) bombardment. Results obtained from 100–120 measurements for each standard dilution show that the relationship between the signal intensity measured and the elemental concentration (μg/mg of wet tissue or mm ) is linear in the range of biological concentrations. This quantitative approach was applied firstly to bromine of the 5-bromo-2′-deoxyuridine (BrdU) used as nuclear marker of rat hepatocytes in proliferation. The second model concerns depletion of calcium concentration in cortical compartment in Paramecium tetraurelia during exocytosis. Then signal standardization in SIMS microscopy allows us to correlate quantitative results with those obtained from other methods.     

Poly-silicon films with low impurity concentration made by hot wire chemical vapour deposition

Analyses of various impurities (O, C, W, Fe, Ni and Cr) in the poly-Si material (both in layers as well as in cell configurations) made by HWCVD have been carried out to judge the quality of this material for application in devices. SIMS analysis showed that the oxygen concentration in the bulk of a poly-Si film made at a low hydrogen dilution (Poly2) is 3×10¹⁸ cm⁻³ and the oxygen content drops to this value within a depth of only 50 nm from the surface. On the other hand, a poly-Si film made at a high hydrogen dilution (Poly1) has a high and homogeneous oxygen content of more than 2×10²¹ cm⁻³. However, in a double-layer structure (Poly2 on top of Poly1), the oxygen content of the bottom layer (Poly1) is significantly smaller than the bare Poly1 film, though this oxygen concentration is still much higher than that in the top Poly2 layer. We attribute this behaviour to the structural difference between these two films (2000 cm⁻¹ Si–H IR vibration in low-dilution material and 2100 cm⁻¹ vibration in the high-dilution material). We propose that the oxygen penetration in Poly1 occurs by two processes: (1) oxygen incorporation during growth: (2) post-deposition oxygen intrusion. The first process occurs at a low deposition rate and is dependent on the type of growth process. The second process is due to the intrusion of water vapour into the film through the voids, which increases the conductivity of the film depending on the amount of intrusion. We have shown that our device quality compact poly-Si : H (Poly2) resists oxygen incorporation even when deposited in an oxygen-rich atmosphere.     

二次离子质谱的深度分辨本领

深度剖析是二次离子质谱在半导体以及各种其它薄膜材料分析中最重要的应用，深度分辨本领是表征其分析能力的重要参数，国际标准化组织（ＩＳＯ）最近 在研究和制定这方面的国际标准。本文在概述了ＳＬＭＳ深度分辨本领影响因素的基础上，推导了δ掺杂层深度分辨函数的解析表达式，讨论了其物理意义，特别是分辨参数的定义。在ＣＡＭＥＣＡ ＩＭＳ ４ｆ仪器上用５．５ｋｅＶ的氧束对Ｓｉ中ＧａＡｓδ掺杂多层膜样品进行了深度剖析，讨论了所得分辨参数及影响因素。结合国外实验室ＩＳＯ巡回测试的结果，对深度分辨参数的定义和评估方法进行了简要评述。     

SIMS quantification of As and In in Hg1−xCdxTe materials of different x values

This paper presents a study of Secondary Ion Mass Spectrometry (SIMS) quantification of As and In in Hg_1–xCd_xTe materials. The SIMS results show that for Hg_1-xCd_xTe with x from 0.2 to 0.8, As and In quantification is independent of the x-values (0.2–0.8). The relative sensitivity factors (RSF) for In and As derived from the standard of one x value can be used to accurately quantify unknown samples of different x value(s). We also determined the dependence of sputtering rate vs. x values under oxygen beam bombardment.     

SIMS测定国际比对铀微粒中铀同位素丰度

Measurement of isotope ratio of uranium in small amounts were required by nuclear safeguards for the control of environmental contamination and the detection of nuclear proliferation. The isotope ratio of uranium particles were determined by SIMS. The result was agreed with the reference values.     

A review of the features and analyses of the solid electrolyte interphase in Li-ion batteries

The solid electrolyte interphase (SEI) is a protecting layer formed on the negative electrode of Li-ion batteries as a result of electrolyte decomposition, mainly during the first cycle. Battery performance, irreversible charge “loss”, rate capability, cyclability, exfoliation of graphite and safety are highly dependent on the quality of the SEI. Therefore, understanding the actual nature and composition of SEI is of prime interest. If the chemistry of the SEI formation and the manner in which each component affects battery performance are understood, SEI could be tuned to improve battery performance. In this paper key points related to the nature, formation, and features of the SEI formed on carbon negative electrodes are discussed. SEI has been analyzed by various analytical techniques amongst which FTIR and XPS are most widely used. FTIR and XPS data of SEI and its components as published by many research groups are compiled in tables for getting a global picture of what is known about the SEI. This article shall serve as a handy reference as well as a starting point for research related to SEI.     

Boron diffusion and activation in polysilicon multilayer films for P MOS structure: Characterization and modeling

This work deals with in situ boron diffusion and activation in multilayer films: polysilicon (Poly1)/amorphous silicon (Poly2). These films are deposited by LPCVD technique. However, several heat treatments were carried in order to determine the optimal annealing conditions to suppress boron penetration from the gate to the substrate through the gate oxide in MOS structure. The boron concentration is monitored by secondary ion mass spectrometry (SIMS). To investigate SIMS profiles we proposed a model of boron diffusion into these multilayer structures. It is important to note that the parameter values of the studied films such as the diffusion coefficient, the activation percentage of boron as well as the acceleration rate of boron diffusion are deduced from adjustment of simulated profiles with experimental profiles. From these results, we inferred that the boron is electrically active and its distribution does not reach the oxide layer and consequently, the Poly2 may reduce the boron diffusion in optimal annealing conditions.     

Effects of hydrogen plasma on passivation and generation of defects in multicrystalline silicon

Hydrogenation by plasma is a low cost and efficient method to improve the photovoltaic properties of multicrystalline silicon. The role of plasma parameters on the efficiency of hydrogenation was studied using secondary ion mass spectrometry (SIMS), hydrogen effusion, electrochemical impedance spectroscopy and electron beam induced current (EBIC). The experimental results showed a deuterium concentration of 10²⁰ atoms cm⁻³ could be reached in the sample after a 15-min treatment. Optimal treatment time depends on temperature and leads to maximum electrical conductivity and minority carrier diffusion length. The results confirm the reduction of defects densities and potential barriers associated with grain boundaries.