双光栅纯转动拉曼测温激光雷达单色仪的光学设计

纯转动拉曼测温激光雷达中采用双光栅单色仪结构的优点是能提供优于10-7抑制比,能够很好地抑制瑞利-米氏散射,得到纯度很高的转动拉曼谱,并且能够提高光的透射率,具有长期稳定性,但双光栅单色仪的光路结构复杂一直是系统中的难点。首先对两种光栅光路结构进行讨论,得出光纤对称式光栅光路结构对于光栅效率的利用要优于光纤直线排列式光路结构,并通过对光栅公式和转动拉曼光谱公式结合,推导出光栅闪耀级次和衍射角关系方程。当光栅常数为600line/mm时,其第5级为最佳闪耀级次。     

Phase Shift Technique for the Measurement of Chromatic Dispersion in Optical Fibers Using LED's

A sinusoidal technique is reported, which allows simple and accurate measurements of chromatic dispersion in optical fibers. It is based on the phase shift which a sinusoidally modulated light beam undergoes while traveling along a fiber when its wavelength is changed. The choice of a multiple LED's source permits the continuous spectral covering from 750 to 1600 nm; easily available instrumentation and devices are needed for the measurement setup. The technique is reported in detail by showing results obtained in multimode fibers; statistical evaluation of its accuracy and a comparison with conventional methods are carried out. An accuracy of a few picosecond in relative delay and of /spl I.chemc/1 ps/nm /spl dot/ km in chromatic dispersion are demonstrated, that compare very favorably with the existing techniques.     

偏轴式扫描三光栅单色仪

为了获得宽波段高分辨率的单色光,对成像光谱仪进行了波长标定,设计了一款扫描式三光栅单色仪。光栅扫描系统采用蜗轮蜗杆机构,针对传统安装方式带来的光栅有效口径损失及杂散光等问题,创造性地提出了蜗轮蜗杆转台偏轴安装的方法,通过蜗轮蜗杆转台初始位置的偏移,有效抑制了扫描过程中光栅实际有效口径的减小和仪器杂散光增加等问题。单色仪光学系统采用水平式C-T结构,通过三块光栅实现280~2 240 nm的宽波段输出,保证整个波段内的高衍射效率和光谱分辨率;并针对蜗轮蜗杆的非线性扫描,使用多种数学模型对单色仪系统进行了光谱定标。最终的实验和测量证明,仪器在280~560 nm、560~1120 nm、1 120~2 240 nm三个波段的光谱分辨率分别为0.1、0.2、0.4 nm,波长重复性分别为0.094、0.186、0.372 nm,波长准确度分别为0.096、0.191、0.382 nm,达到了设计目标,满足成像光谱仪波长定标的使用要求。     

In-line monitoring of 300 mm silicon epitaxial and CZ wafers using surface charge profiler

The surface charge profiler (SCP) offering non-contact electrical characterization of the near-surface region of silicon wafers is discussed. The system permits fully automatic handling of 300- and 200-mm wafers. The SCP method, based on a low intensity illumination a.c. surface photo-voltage principle, does not require any surface preparation. It allows for a fast (600 points/min), high-resolution mapping of the active doping concentration in the near-surface region as well as surface recombination lifetime. The capabilities of the SCP method for process monitoring and development are illustrated with 200- and 300-mm wafers, focusing on the effects of epi growth conditions on the layer uniformity and its resistivity.     

A novel technique for measurement of the mode indexes of channelwaveguides

An accurate technique for measurement of small differences in the mode indexes of channel waveguides is presented and compared with the prism coupler. It has a distinct advantage over the prism coupler method since it allows measurements in buried waveguides as well. The absolute mode index of an individual guide can also be obtained provided a guide near the mode cutoff is available on the same substrate. The technique is expected to be useful with waveguides of high index materials, especially when the prism coupler monitoring the uniformity of optical fibers or measuring the waveguide birefringence     

变包含角平面光栅单色器的性能检测

针对高分辨变包含角平面光栅单色器(VAPGM)工作在超高真空环境下需具有极高的精度,本文基于自准直法.研究了VAPGM波长扫描机构转角精度、光斑水平漂移重复精度以及光栅切换机构重复精度的检测方法.利用该方法完成了VAPGM的离线检测,其中,波长扫描机构平面镜(PM)和平面光栅(PG)的转角精度检测结果分别为0.19"、...     

转动喇曼雷达双光栅单色仪透过率函数的算法

双光栅单色仪的透过率函数对转动喇曼激光雷达回波信号的模拟计算、温度反演灵敏度的分析、温度反演公式的选择等具有重要作用。为了研究双光栅单色仪透过率函数的算法,采用一个变量把衍射光斑占出射光纤横截面积的比表示出来,然后利用光斑与光纤横截面是相离、相交还是相切的关系给出了透过率函数,对532nm的双光栅单色仪的透过率函数进行了理论分析与实验研究。结果表明,532nm双光栅单色仪的透过率曲线的中心波长分别为529.0nm,530.3nm,533.8nm和535.1nm,带宽为0.48nm,模拟的回波信号与实测回波信号基本重合,双光栅单色仪透过率函数的计算方法是正确的。     

转动拉曼测温激光雷达的双光栅单色仪研究

纯转动拉曼测温激光雷达中采用双光栅单色仪结构的优点是能提供优于10-7的抑制比,能够很好抑制Rayleigh-Mie散射,得到纯度很高的转动拉曼谱,并且能够提高光的透过率,具有长期的稳定性.光纤、透镜、光栅参数的选择及焦板上光斑的精确定位是双光栅单色仪研制成败的关键.在合适的参数下计算出了双光栅单色仪的滤波函数,高低量子数回波信号强度比以及温度随高度的变化,计算出的温度与代入的温度相差约0.3 K,说明此双光栅单色仪的设计是合理的.     

面阵CCD探测的全自动椭圆偏振光谱系统研究

给出了一种椭圆偏振光谱的快速测量方法，并使得实验系统的结构更为紧凑和小型化，减轻了重量，研究中采用了由面阵型CCD探测器和平面多光栅组成的光谱仪，无需光栅扫描，就能够在很短时间内对光谱进行快速准确的数字凝视式成像，光谱分辨精度优于1．0mm，显著提高了系统工作的可靠性和效率，系统采取了将CCD光谱仪后置的方式，研究并解决了从物理光学原理，器件设计和加工、系统调试和定标、软件编制以及到光谱测量和数据分析等一系列问题，实验中对典型贵金属Au的光学常数谱进行了测量，获得了满意的结果。     

Trench sidewall implantation with a parallel scanned ion beam

The sidewalls of trenches on 100-mm wafers were doped by implantation with an implanter whose beam scan is accurately parallel over the whole wafer surface. The doping was characterized with a staining technique and transmission electron microscopy. All the trenches exhibited symmetrical doping, with the main differences between trenches from the center and edge of a wafer being due to nonuniformity of the trench etching rather than the implant step. Although the measurements were made on 100-mm wafers, symmetrical doping should be achievable for all trenches on wafers up to 200 nm in diameter     

Low-k dielectrics: a non-destructive characterization by infrared spectroscopic ellipsometry

An infrared spectroscopic ellipsometer devoted to the characterization of silicon microelectronics has recently been developed at SOPRA. Its main feature is the ability to measure on a small spot (80×200 μm) with a high signal/noise ratio. An original patented optical design suppresses back face reflection and ensures good-quality spectral measurements in the 600–7000 cm⁻¹ range. The excellent signal/noise ratio allows the performance of measurements in less than 30 s. Automation and real-time analysis are included to offer an operator-orientated metrology tool. Details of the instrument are presented, and its use for the characterization of different kinds of low-k dielectrics.     

Temperature-independent accelerometer using a fiber Bragg grating incorporating a biconical taper

An intensity-modulated optical fiber accelerometer is proposed and experimentally demonstrated by using a fiber Bragg grating (FBG) incorporating a biconical fiber taper. Acceleration-induced microbending of the fiber taper region introduces various attenuation to the light, so that acceleration can be measured from changes of the optical power of the reflected light from the FBG. This power detection method reduces the cost and complexity of the sensor setup since only photodetector is required for the signal detection. In the static measurement, a relatively large range of 5g (g is gravity, equals to 9.8 m/s²) with sensitivity of 4.85 nW/g is achieved. Vibration measurements have also been carried out with a frequency up to 20 Hz. The proposed accelerometer is nearly independent of temperature because the reflected optical power of the FBG is insensitive to temperature.     

Optical,non-destructive characterization of ultra-shallow junctions

As ULSI technology moves below the 180 nm technology node, tight control of the depth of ultra-shallow junctions (USJ), such as those used in source-drain extensions, becomes critical. The problem is one of both local control and uniformity over the full area of 200 and 300 mm wafers. This paper describes the status of carrier illumination™ (CI), an optical method for measuring the active junction depth for ultra-shallow source-drain extensions. It features a non-destructive, high throughput measurement with a spot size of less than 2 μm. This provides rapid uniformity measurements on patterned wafers, enabling in-line control of USJ processes. CI is based on injecting excess carriers that line up with the active doping profile. These carriers act as a “contrast agent” allowing an optical interferometer to measure their profile. The active junction depth may then be deduced from the interferometer signal. This paper first describes the CI measurement and motivation for its development. It then presents a summary of qualification results on PMOS and NMOS process flows. These demonstrate use of the measurement at the process steps associated with extension and source/drain (SD) formation, on both bare and patterned wafers. Correlation is shown to SIMS, SRP, sheet resistance, and transistor and test structure electrical measurements.     

An industrial SR-TXRF facility at ESRF

A TXRF industrial facility for the mapping of trace impurities on the surface of 300-mm Silicon wafers is presently in the construction phase and will start the commissioning phase at the end of 1998. The elements to be detected range from Na to Hg with a target routine detection limit of 10⁸ at/cm² and the capability of mapping the surface of 300-mm wafer with a resolution of 500 pixels and a throughput of three wafers/h.     

A survey of automated material handling systems in 300-mm SemiconductorFabs

The fast-paced developments and technological breakthroughs in the semiconductor manufacturing industry elevates the importance of optimum utilization of resources. The newer 300-mm wafers fabs place a high level of emphasis on increasing yield and reducing cycle times. Automated material handling systems are importanttools that help us achieve these objectives. In addition, due to the increased weight and size of 300-mm wafers, an automated material handling system isa must for a 300-mm manufacturing facility. This paper discusses various approaches for automated materials handling in semiconductor manufacturing industries.     

消除温度对应变测量的影响

提出了用光纤布喇格光栅( FBG)传感器测量光纤有效弹光系数的方法。利用光纤布 喇格光栅的性质,建立了一个可以有效地解决温度与应变对光栅存在交叉敏感的问题实验系统。实验结果表明,该系统能有效地测出了光纤的有效弹光系数,而且测量误差小于1. 3%。     

Warpage measurement of large area multitilted silicon substrates atvarious processing conditions

In order to find a low-cost solution for the future MCM-D packaging, a multitiling approach through the incorporation of several tiles on a large carrier substrate was studied. The multitiling format provides simultaneous processing of several small silicon wafers on a carrier glass with a coefficient of thermal expansion (CTE) comparable to that of silicon. The wafers (tiles) are attached to the carrier glass (pallet) using a low modulus adhesive that can be released at an elevated temperature (~450°C). The objective of this study is to develop materials and processes for a 12-in×12-in (300-mm×300-mm) large area substrate that can be scalable up to a 600-mm×600-mm format. The fabrication process begins with a carrier CTE matched Borofloat glass on which silicon wafers are attached using a low modulus adhesive. This composite structure is exposed to high temperature thin-film processes that are required for the MCM-D manufacturing. The warpage of these structures is a critical factor that determines the processability of the thin films in a manufacturing environment. Specimen warpage was obtained using the shadow moire technique. Warpage measurement was performed (i) on as-received glasses, (ii) glasses after polishing, and (iii) pallet assembly after tiling was completed. Although polishing reduced the overall warpage of the as-received pallets, the warpage of the tile and pallet assembly was increased after the adhesive was cured at 150°C. This paper discusses the warpage issues associated with various stages of processing of the proposed large area MCM-D structures     

一种基于径向偏振解调的线性光学电流传感器

提出了一种基于径向偏振解调的线性光学电流传感器。采用集磁式传感头,由两块导磁板将气隙磁场引出,直通式光路由通光孔经过气隙磁场,不需要反射棱镜,根除了反射相移,有利于改善传感器的稳定性。采用径向偏振光栅将法拉第旋转角转换为环形光斑的同步转动,由四象限探测器对光斑定位得到待测电流。经理论分析和实验验证,传感器的测量模式与光强无关,法拉第旋转角测量范围为43,测量准确度0.2S级。     

Broad-passband-width optical filter for multi/demultiplexer using a diffraction grating and a retroreflector prism

The letter describes the experimental results of a novel optical filter for a multi/demultiplexer using a diffraction grating and a retroreflector prism. A broader passband width, which is proportional to the difference between the prism base length and the input fibre core diameter, is obtained. The minimum insertion loss is 2.2 dB.     

High-efficiency 35-GHz GaAs MESFET's

Ka-band GaAs FET's with power output in excess of 200 mW and with efficiencies of more than 20 percent are described. Both ion-implanted and VPE-grown wafers were used. Deep UV (300-nm) lithography and chemical etching was employed to obtain a final gate length of 0.5 µm. These FET chips were flip-chip mounted and had a very low thermal resistance of 50°C/W for a total source periphery of 0.6 mm. At 35 GHz an output power of 220 mW with 21-percent efficiency at 3-dB gain was obtained from a 0.6-mm cell.