UHV/CVD生长SiGe/Si异质结构材料

以Si_2H_6和GeH_4作为源气体，用UHV/CVD方法在Si(100)衬底上生长了Si_(1-x)Ge_x合金材料和Si_(1-x)Ge_x/Si多量子阱结构。用原子力显微镜、X光双晶衍射和透射电子显微镜对样品的表面形貌、均匀性、晶格质量、界面质量等进行了研究。结果表明样品的表面平整光滑，平均粗糙度为1.2nm；整个外延片各处的晶体质量都比较好，各处生长速率平均偏差3.31%，合金组分x值的平均偏差为2.01%;Si_(1-x)Ge_x/Si多量子阱材料的X光双晶衍射曲线中不仅存在多级卫星峰，而且在卫星峰之间观察到了Pendellosung条纹，表明晶格质量和界面质量都很好；Si_(1-x)Ge_x/Si多量子阱材料的TEM照片中观察不到位错的存在。

ECR Plasma CVD淀积介质膜折射率的神经网络模拟

用人工神经网络方法对电子回旋共振等离子法化学气相沉积(ECR Plasma CVD)镀膜工艺建立了一个介质膜折射率n关于气流配比Q(N_2)/Q(SiH_4)和Q(Q_2)/Q(SiH_4)的数学模型。在给定气流配比Q(N_2)/Q(SiH_4)和Q(O_2)/Q(SiH_4)时模型预测的成膜折射率与实验值符合得很好。

ECR Plasma CVD法淀积介质膜技术在半导体光电器件中的应用

电子回旋共振等离子体化学气相淀积(ECR Plasma CVD)法淀积介质膜技术是制备性能优良的光电子器件光学膜和电介质膜的重要手段之一。该文报道了ECR Plamsa CVD法淀积介质膜的工艺以及介质膜的特性等。

ECR Plasma CVD法淀积808nm大功率半导体激光器光学膜工艺研究

介绍了电子回旋共振等离子体化学气相沉积(简称ECR Plasma CVD)法淀积808nm大功率半导体激光器两端面光学膜的工艺，给出工艺条件，探索了膜系监控的方法和优越性，讨论了这种淀积方法的优点和淀积的光学膜的优良特性。

Comparison of GexSi1—x Grown by UHV／CVD from Si2H6／GeH4 and SiH4／GeH4

国家自然科学基金

GeSi CVD系统的流体力学和表面反应动力学模型

于2010-11-23批量导入

Influence of heated catalyzer on thermal distribution of substrate in HWCVD system

Based on Stefan-Boltzman and Lambert theorems, the radiation energy distribution on substrate (REDS) from catalyzer with parallel filament geometry has been simulated by variation of filament and system layout in hot-wire chemical vapor deposition. The REDS uniformity is sensitive to the distance between filament and substrate d(f-s) when d(f-s) less than or equal to 4 cm. As d(f-s) > 4 cm, the REDS uniformity is independent of d(f-s) and is mainly determined by filament number and filament separation. Two-dimensional calculation shows that the REDS uniformity is limited by temperature decay at filament edges. The simulation data are in good agreement with experiments. (C) 2003 Elsevier Science B.V. All rights reserved.

Type-II SiGe/Si MQWS (multi-quantum wells) and self-organized Ge/Si islands grown by UHV/CVD system

Type-II SiGe/Si MQWs (Multi-Quantum Wells) and Self-Organized Ge/Si Islands were successfully grown by a homemade ultra-high vacuum/chemical vapor deposition (UHV/CVD) system. Growth characteristics and PL (photoluminescence) spectra at different temperature were measured. It demonstrated that some accumulation of carriers in the islands results in the increase of the integrated PL intensity of island-related at a certain temperature range.

Structural evaluation of polycrystalline silicon thin films by hot-wire-assisted PECVD

Tungsten wires were introduced into a plasma-enhanced chemical vapor deposition (PECVD) system as a catalyzer: we name this technique 'hot-wire-assisted PECVD' (HW-PECVD). Under constant deposition pressure (p(g)), gas flow ratio and catalyzer position, the effects of the hot wire temperature (T-f) on the structural properties of the poly-Si films have been characterized by X-ray diffraction (XRD), Raman scattering and Fourier-transform infrared (FTIR) spectroscopy. Compared with conventional PECVD, the grain size, crystalline volume fraction (X-e) and deposition rate were all enhanced when a high T-f was used. The best poly-Si film exhibits a preferential (220) orientation, with a full width at half-maximum (FWHM) of 0.2 degrees. The Si-Si TO peak of the Raman scattering spectrum is located at 519.8 cm(-1) with a FWHM of 7.1 cm(-1). The X-c is 0.93. These improvements are mainly the result of promotion of the dissociation of SiH4 and an increase in the atomic H concentration in the gas phase. (C) 2001 Elsevier Science B.V. All rights reserved.

Ignition of single coal particle in a hot furnace under normal- and micro-gravity condition

An experimental study on ignition and combustion of single particles was conducted at normal gravity (1-g) and microgravity (l-g) for three high volatile coals with initial diameter of 1.5 and 2.0 mm, respectively. The non-intrusive twin-color pyrometry method was used to retrieve the surface temperature of the coal particle through processing the images taken by a color CCD camera. At the same time, a mathematical model considering thermal conduction inside the coal particle was developed to simulate the ignition process. Both experiments and modeling found that ignition occurred homogeneously at the beginning and then heterogeneously for the testing coal particles burning at l-g. Experimental results confirmed that ignition temperature decreased with increasing volatile content and increasing particle size. However, contradicted to previous studies, this study found that for a given coal with certain particle size, ignition temperature was about 50–80 K lower at l-g than that at 1-g. The model predictions agreed well with the l-g experimental data on ignition temperature. The criterion that the temperature gradient in the space away from the particle surface equaled to zero was validated to determine the commence of homogeneous ignition. Thermal conduction inside the particle could have a noticeable effect for determining the ignition temperature. With the consideration of thermal conduction, the critical size for the phase transient from homogeneous to heterogeneous is about 700 lm at ambient temperature 1500 K and oxygen concentration 0.23. 2009 The Combustion Institute. Published by Elsevier Inc. All rights reserved.

Effects of magnetic configuration on hot electrons in highly charged ECR plasma

To investigate the hot electrons in highly charged electron cyclotron resonance (ECR) plasma, Bremsstrahlung radiations were measured on two ECR ion sources at the Institute of Modern Physics. Used as a comparative index of the mean energy of the hot electrons, a spectral temperature, Tspe, is derived through a linear fitting of the spectra in a semi-logarithmic representation. The influences of the external source parameters, especially the magnetic configuration, on the hot electrons are studied systematically. This study has experimentally demonstrated the importance of high microwave frequency and high magnetic field in the electron resonance heating to produce a high density of hot electrons, which is consistent with the empirical ECR scaling laws. The experimental results have again shown that a good compromise is needed between the ion extraction and the plasma confinement for an efficient production of highly charged ion beams. In addition, this investigation has shown that the correlation between the mean energy of the hot electrons and the magnetic field gradient at the ECR is well in agreement with the theoretical models.中文摘要：ECR(电子回旋共振)离子源是产生稳定的强流多电荷态离子束流最有效装置。全永磁 ECR 离子源因其独特的特点为很多中小型多电荷态离子束流实验平台与离子注入机等系统所采用，为后者产生重复性好、稳定性强的多电荷态离子束流。本文着重论述了中国科学院近代物理研究所研制的几台全永磁多电荷态ECR离子源及其特性与典型性能，如能产生强流高电荷态离子束流的高性能全永磁离子源LAPECR2，能产生强流中低电荷态离子束流的LAPECR1，能产生多电荷态重金属离子束流的LAPECR1-M等。这些性能稳定的离子源为提高近代物理研究所相关试验平台的性能提供了关键的束流品质保障。