基于电感耦合等离子体的InP基半导体材料干法刻蚀的研究

研究了基于电感耦合等离子体(ICP)刻蚀系统的InP基半导体材料的干法刻蚀.采用Cl2/Ar/H:混合刻蚀气体,分别研究了氯气体积分数和ICP功率与刻蚀速率之间的关系,及镍、二氧化硅和二者结合型掩膜版的适用范围.获得有效的刻蚀速率为450～1 200 nm/min,InP对金属镍的选择性刻蚀比值为175～190.掩膜版...     

Inductively Coupled Plasma and Electron Cyclotron Resonance Plasma Etching of an InGaAlP Compound Semiconductor System

Current and future generations of sophisticated compound semiconductor devices require the ability for submicron scale patterning. The situation is being complicated because some of the new devices are based on a wider diversity of materials to be etched. Conventional RIE (reactive ion etching) has been prevalent across the industry so far, but has limitations for materials with high bond strengths or multiple elements. In this article, we suggest high-density plasmas such as ECR (electron cyclotron resonance) and ICP (inductively coupled plasma), for the etching of ternary compound semiconductors (InGaP, AlInP, AlGaP) that are employed for electronic devices such as heterojunction bipolar transistors (HBTs) or high electron mobility transistors (HEMTs), and photonic devices such as light-emitting diodes (LEDs) and lasers. Operating at lower pressure, high-density plasma sources are expected to meet target goals determined in terms of etch rate, surface morphology, surface stoichiometry, selectivity, etc. The etching mechanisms that are described in this article can also be applied to other III-V (GaAs-based, InP-based) as well as III-Nitride, because the InGaAlP system shares many of the same properties.     

Deep InP Gratings for Opto-Electronic Devices Etched by C12/CH4/Ar Inductively Coupled Plasma

Deep InP gratings are etched by C12/CH4/Ar inductively coupled plasma （ICP） at room temperature. A comparison is made between SiNz mask patterns formed by wet and dry etching. SF6 reactive ion etching is adopted for smooth and vertical sidewall. The etching conditions of C12/CH4/Ar ICP are optimized for high anisotropy, and a 1.7-μm-deep InP grating with an aspect ratio of 10：1 is demonstrated. The technique is then used for the fabrication of 1.55-μm laterally coupled distributed feedback A1GMnAs-InP laser.     

Generation of Optical Vortex Using a Spiral Phase Plate Fabricated in Quartz by Direct Laser Writing and Inductively Coupled Plasma Etching

A simple, economical and reliable technique is proposed for fabricating a spiral phase plate （SPP） in a quartz substrate to generate optical vortex with a unit topological charge at the wavelengths of 632.8nm. The spiral phase plate is first formed in the photoresist by direct laser writing lithography and then transferred into the quartz substrate by inductively coupled plasma etching. The performance of the fabricated SPP is verified by using beam intensity distribution, which is in agreement with the theoretical calculation result. The interference measurement suggests that we have succeeded to generate optical vortex with a unit topological charge with the fabricated SPP.     

Effect of hydrostatic pressure on N(CH3)4+ cation motion in ferroelectric N(CH3)4H(Cl3CCOO)2

The proton spin-lattice relaxation time in ferroelectric N(CH3)4H(Cl3CCOO)2 has been studied under isobaric conditions at pressures 0.1, 200 and 400 MPa over a wide range of temperature. The data indicate that the dominant relaxation mechanism for T1 can be attributed to the classical CH3 group reorientation of N(CH3)4+ cation. The influence of pressure on methyl group reorientation of N(CH3)4+ cation was analysed.     

毛细管电泳电感耦合等离子体原子发射光谱法分析铁的形态

用毛细管电泳电感耦合等离子体原子发射光谱法研究了Fe2+-Fe3+在络合剂o-phen中,混合络合试剂o-phen和EDTA中的形态分离,以及游离态Fe2+-Fe3+的分离。考察了电压、缓冲液的pH值和络合剂浓度等对游离态铁形态分离的影响,获得了满意的分离条件。在分析过程中,阳离子、阴离子、以及络合试剂均不产生干扰,该方法优于毛细管电泳紫外-可见光谱法。     

CH4/H2和CH4/He体系等离子体发射光谱分析

 在CH₄/H₂和CH₄/He和CH₄/He两种系统中,利用光学发射谱技术对螺旋波放电产生低压甲烷等离子体内活性粒子的光学发射特征进行了原位诊断。在实验中,两种体系下同时都测得的主要荷电粒子为CH,Ha,Hb,Hg以及H2等。研究了各实验参数对这些活性粒子CH, Ha,Hb以及Hg的发射光谱强度的影响。结果表明：在CH₄/H₂体系下,随着射频功率的增大,Ha,Hb,Hg以及CH基团的相对强度都随着增加,而当放电气压变化时它们都呈现先增大而后减小的趋势。在CH₄/He体系下,随射频功率的增加,Ha,Hb,Hg以及CH相对强度变化的总体趋势也都是先增加而后减小,当工作气压增加时,Ha,Hb以及Hg的相对强度变化也是呈现先增大而后减小,但CH基团的相对强度却是逐渐减小的;这些结果为等离子体沉积各种薄膜过程的理解及制备工艺参数的调整提供了参考。     

Room-Temperature Photonic Crystal Laser in H3 Cavity on InGaAsP/InP Slab

We fabricate and investigate two-dimensional photonic crystal H3 microcavities in an InGaAsP slab. The lasing action at room temperature is observed. The lasering threshold is 7mW under the pulsed pump of 0.75% duty cycle. The Q factor and the lasing mode characteristics are simulated by three-dimensional finite difference time domain method. The simulation result matches well with the experiment.     

射频感应耦合低压等离子体特性分析

采用光谱诊断法和Langmuir单探针法对射频感应耦合Ar气等离子体特性进行分析。通过光栅光谱仪研究了低气压下Ar气等离子体的光谱强度的变化特性,采用Langmuir单探针法测量不同条件下电子密度和电子温度。等离子体发射光谱的光谱强度随着气压和功率的增加而增强,射频功率对光谱强度的影响较明显。当功率从120W增加到180W时,光谱强度将会迅速增加,等离子体发生E模向H模的模式转换。Langmuir单探针法测量的电子密度和电子温度在的变化规律符合E模向H模转换的变化规律。     

PS－4型电感耦合等离子体发射光谱仪故障检修二例

本文介绍了等离子体发射光谱仪在作汞灯准直时，所出现的两个故障排除方法，以及应急状态下对线路进行的处理。     

野生藜蒿中的微量元素的质谱分析

研究应用电感耦合等离子体串联质谱(ICP-MS/MS)技术建立准确测定野生藜蒿中12个微量元素的分析方法。采用MS/MS模式,以O₂为反应气,元素As和Se与O₂发生质量转移反应生成AsO和SeO,通过测定AsO和SeO消除质谱干扰;以NH₃/He为反应气,元素Cr,Mn,Fe,Co,Ni,Cu,Zn与NH₃/He发生质量转移反应形成团簇离子,通过测定团簇离子消除质谱干扰。元素Cd,Hg和Pb采用标准模式进行测定。12个待测元素的校准曲线在0～200 μg·L-1范围内具有良好的线性关系,各元素的检出限为0.64～49.61 ng·L-1。通过测定国家标准物质芹菜(GBW10048),采用t检验法进行差异性检验表明,测定值与标准值之间无显著性差异,验证了方法的准确可靠性。各元素的加标回收率在92.0%～106.1%之间,相对标准偏差(RSD)为1.6%～4.9%。分析了来自国内不同地区的4个野生藜蒿样品,结果显示,不同来源样品中12个元素的含量各有差异,Mn,Fe,Zn的含量远高于其余九种元素,毒理性元素As,Cd,Hg和Pb的含量处于极低水平。方法能准确测定野生藜蒿中的多种微量元素,为野生藜蒿的食用营养和安全提供科学的理论依据。     

电感耦合等离子体串联质谱法分析麻疯树油中的多元素

工业化和现代化进程的加快消耗了大量能源,对能源的高度依赖性导致了全球化石能源需求的快速增长,随着非再生化石能源的日渐枯竭,迫切需要大力发展可再生能源以调整现有能源结构。作为国际上研究最多的生物柴油,麻疯树油是国内外公认的最有可能替代化石能源的再生能源,具有极大的开发潜力。麻疯树油中的微量元素在燃烧过程中会影响发动机的性能,并在尾气排放过程中决定了对环境所造成的污染程度。本文以获得麻疯树油中多元素的含量为目的,建立应用电感耦合等离子体串联质谱(ICP-MS/MS)法准确测定麻疯树油中低水平Na,Si,P,S,Cl,K,Ti,V,As含量的分析方法。采用微波密闭消解系统,依次向麻疯树油样品中加入硝酸和双氧水进行消解。详细地研究了各待测元素在不同分析模式下检出限(DL)和背景等效浓度(BEC)的变化情况,在MS/MS模式下,通过向碰撞/反应池(CRC)中加入反应气可以完全消除质谱干扰。选择O₂为反应气,P+,S+,Ti+,V+,As+与O₂的反应均为放热过程,能发生质量转移自发生成PO+,SO+,TiO+,VO+,AsO+,利用O₂质量转移法消除质谱干扰;选择H₂为反应气,Cl+与H₂反应能自发生成ClH+₂,利用H₂质量转移法消除质谱干扰,而Na+,Si+,K+均不能与H₂发生质量转移反应,利用H₂原位质量法消除质谱干扰。选择Sc为内标元素校正了分析过程中的基体效应。通过考察不同反应气流速下各元素的BEC变化,优化了反应气流速,O₂的最佳流速为0.45 mL·min-1,H₂的最佳流速为7.5 mL·min-1。在优化的实验条件下获得Na,Si,P,S,Cl,K,Ti,V,As的检出限分别为6.41,37.3,24.6,118,530,7.96,7.61,0.34,3.20 ng·L-1,各元素在0～50 μg·L-1范围内的线性相关系数(R2)≥0.999 8,方法具有良好的线性关系。采用三水平加标回收实验来验证方法的准确性和精密度,所有元素的加标回收率在91.2%～108%之间,相对标准偏差(RSD)为1.9%～4.6%,表明所建立的方法准确性好,精密度高。通过对来自中国不同地区的4个麻疯树油样品进行测定,结果显示,4个麻疯树油样品中P含量≤164 ng·g-1,S含量≤2310 ng·g-1,碱(Na+K)含量≤1 690 ng·g-1,三项指标均达到了中国生物柴油调和燃料国家标准,欧Ⅳ生物柴油标准,德国生物柴油标准和美国生物柴油标准。这项研究为麻疯树油中多种微量元素的准确分析提供了一种方便可行的新方法,为麻疯树油的质量控制和安全应用提供了科学的理论依据。     

1H NMR study of N(CH3)4H(ClF2CCOO)2

The proton spin–lattice relaxation times and ¹H NMR second moments were measured over a wide range of temperature. The results were compared with those of the ¹⁹F NMR relaxation that we obtained earlier. For both nuclear species, the evolution of the longitudinal magnetizations with time is observed to be strongly bi-exponential and were in good quantitative agreement with the cross-relaxation theory.     

Dynamics of Ring-to-Volume Discharge Transition in H Mode in Inductively Coupled Plasma Torches at Atmospheric Pressure

The transition process in ring-to-volume discharge in H mode in inductively coupled plasma torches at atmospheric pressure is investigated by analyzing the time resolved image taken by a high speed camera. The effects of input power, plasma working gas flow rate, and its composition on the transition dynamics are also discussed.The results show that the discharge plasma has experienced ring discharge, and the development stage diffused from the boundary to the center in the confinement tube, and steady volume discharge after entering the H mode. Increasing input power, sheath gas flow rate and hydrogen contents in plasma working gas are all able to lessen the time consumed in the transition process in ring-to-volume discharge.     

Ar介质感应耦合等离子加热器能量转化与流动特性

对感应耦合等离子(inductively coupled plasma,ICP)加热器内能量转化过程与分布规律、 流动特性的研究和认识能够为高频等离子加热器的设计提供理论指导,同时能够为加热器向大功率、多介质、广适用方向的发展提供支撑.基于二维轴对称、层流流动和局部热力学平衡等假设条件,利用COMSOL对百千瓦级Ar介...     

电感耦合等离子体质谱法测定锰酸锂中杂质元素

采用硝酸+盐酸混合酸消解体系对锰酸锂样品进行微波消解处理制样,用电感耦合等离子体质谱(ICP-MS)法同时测定锰酸锂中Na,Mg,Al,K,Ca,Ti,Cr,Fe,Cu,Zn,As,Ag,Cd,Pb共14种杂质元素的含量。详细研究了质谱干扰影响及校正,选用Sc,Rh,Tl作内标元素校正基体效应和信号漂移,对14种待测元素的检出限为0.007～0.209μg.L-1,通过添加标准进行加标回收,所有待测元素的回收率在92.66%～108.34%之间,相对标准偏差(RSD)均小于4.80%,结果准确可靠。该法可为锰酸锂中杂质元素的快速检测提供科学依据。     

催化前驱体亚硝酰硝酸钌中杂质元素的质谱分析

钌催化前驱体是影响负载型钌催化剂催化性能最重要因素。前驱体中的部分杂质会对催化性能产生抑制作用,尤其是S,P,Cl,As等杂质元素含量过高会降低催化剂的活性,严重时会造成催化剂中毒;因此,必须严格控制催化前驱体中杂质元素的含量。建立了快速准确测定催化前驱体亚硝酰硝酸钌（Ru(NO)(NO₃)₃）中杂质元素的分析方法。Ru(NO)(NO₃)₃经稀硝酸溶解后采用电感耦合等离子体串联质谱（ICP-MS/MS）直接测定其中的8个杂质元素（P,S,Ti,V,Cr,Mn,Fe,As）。为防止Ru(NO)(NO₃)₃溶液水解形成Ru(NO)(NO₃)x(OH)_3-x,采用稀硝酸介质有效维持了样品溶液的稳定性。在MS/MS模式下,通过一级四极杆质量过滤器（Q₁）控制进入碰撞/反应池（CRC）的离子,仅允许与待测元素具有相同质荷比（m/z）的离子进入CRC,从而将来自样品基质和等离子气Ar所形成的干扰离子阻止在CRC外,消除了大量质谱干扰。通过向CRC内通入O₂为反应气,目标离子P+,S+,Ti+,V+,As+与O₂的反应为放热过程（31P++O₂→31P16O++O,ΔH_r=-3.17 eV;32S++O₂→32S16O++O,ΔH_r=-0.34 eV;48Ti++O₂→48Ti16O++O,ΔH_r=-1.63 eV;51V++O₂→51V16O++O,ΔH_r=-0.85 eV;75As++O₂→75As16O++O,ΔH_r=-0.63 eV）,能自发反应生成氧化物离子;目标离子Cr+,Mn+与O₂的反应为吸热过程（52Cr++ O₂→52Cr16O++O,ΔH_r=+1.38 eV;55Mn++O₂→55Mn16O++O,ΔH_r=+2.15 eV）。为促进Cr+,Mn+与O₂发生反应,通过调整CRC的工作参数,设置八极杆偏置电压为较大的负电压,使Cr+和Mn+在与O₂反应前被加速,提高Cr+和Mn+的动能,促进了反应的发生,通过吸热反应生成氧化物离子;而P+,S+,Ti+,V+,Cr+,Mn+,As+干扰离子在CRC内不能与O₂发生反应,仍然保持原始的m/z。通过二级四极杆质量过滤器（Q₂）将这些干扰离子阻止在外,仅允许所形成的氧化物离子进入检测器,几乎完全消除了元素P,S,Ti,V,Cr,Mn,As的所有质谱干扰。NH₃因含一对孤对电子而具有高反应活性,能与很多金属离子反应形成团簇离子。通过向CRC内通入NH₃/He为反应气,目标离子Fe+与NH₃发生质量转移反应,在所形成多个团簇离子中,Fe(NH₃)+₂的丰度最高且无干扰,通过NH₃质量转移法消除干扰。结果显示,8个元素在0～500 μg·L-1范围内具有良好的线性关系,线性相关系数≥0.999 8。方法的检出限为0.29～485 ng·L-1,按所建立的方法分析了实际样品中8个杂质元素的含量,各元素的加标回收率为93.2%～107.5%,相对标准偏差（RSD）≤3.9%。方法具有样品处理简单、分析速度快和精密度高的特点,适合催化前驱体亚硝酰硝酸钌中多个杂质元素的准确测定,为制备负载型钌催化剂提供了质量保障。     

用扫描式电感耦合等离子体光谱仪测定红矾钾产品中的杂质

应用电感耦合等离子体发射光谱法测定了铬盐清洁工艺红矾钾产品中的微量元素硅、铝、铁、钙、锰、镁和氯。采用基体匹配法消除了大量基体的干扰。实验的优化条件为RF发生器的入射功率095kW;载气压力013MPa,流量12L·min-1;辅助气流量02L·min-1。元素氯用氯化银沉淀间接测定,在6%的硝酸体系中氯离子形成氯化物完全沉淀,在50℃陈化2h后进行测定。样品的加标回收率在90%～104%,RSD<4%,检出限在10-4%～10-5%。随机抽样的分析结果与标准加入法吻合较好,相对误差在-427%～ 526%。本方法用于实际样品分析,快速简单,结果令人满意。     

Laser Ablation Inductively Coupled Plasma Mass Spectrometry: Principles and Applications

Abstract

The application of laser ablation inductively plasma mass spectrometry (LA‐ICP‐MS) to the determination of major, minor, and trace elements as well as isotope‐ratio measurements offers superior technology for direct solid sampling in analytical chemistry. The advantages of LA‐ICP‐MS include direct analysis of solids; no chemical dissolution is necessary, reduced risk of contamination, analysis of small sample mass, and determination of spatial distributions of elemental compositions. This review aims to summarize recent research to apply LA‐ICP‐MS, primarily in the field of environmental chemistry. Experimental systems, fractionation, calibration procedures, figures of merit, and new applications are discussed. Selected applications highlighting LA‐ICP‐MS are presented.