多孔硅基发光材料的研究进展

介绍了多孔硅经表面钝化后,其发光强度和谱线峰位的稳定性,以及多孔硅激光染料镶嵌膜的荧光光谱等方面的最新成果。     

水冷反应室成MWPCVD制备金刚石膜装置研制

微波等离子体化学气相沉积（MWPCVD）是制备金刚石膜的一种重要方法。为了获得金刚石膜的高速率大面积沉积,研制成功了水冷反应室式MWPCVD制备金刚石膜的装置,装置在微波输入功率为3.0kW时能长时间稳定运行,并在硅衬底上沉积出金刚石膜。     

水冷反应室式MWPCVD制备金刚石膜装置研制

微波等离子体化学气相沉积(MWPCVD)是制备金刚石膜的一种重要方法.为了获得金刚石膜的高速率大面积沉积,研制成功了水冷反应室式MWPCVD制备金刚石膜的装置.装置在微波输入功率为3.0 kW时能长时间稳定运行,并在硅衬底上沉积出金刚石膜.     

采用MPCVD法在硅衬底上选择性生长金刚石膜

采用微波等离子体化学气相沉积（MPCVD）法在附有SiO2掩摸的硅衬底上选择性沉积出了金刚石膜。采用扫描电子显微镜（SEM）和Raman光谱仪对金刚石膜的表面形貌和结构进行了表征。并讨论了衬底温度对金刚石薄膜选择性沉积的影响。得出了较佳的沉积条件。     

金刚石膜辐射探测器的研究进展

阐述了金刚石作为激发材料在辐射探测器中的应用范围,比较了硅、化学气相沉积(CVD)金刚石膜和天然金刚石作为探测器用激发材料的性能优劣,介绍了CVD金刚石膜辐射探测器的原理和结构,综述了金刚石辐射探测器的国内外研究进展,展望了CVD金刚石膜辐射探测器的应用前景.     

不同衬底上沉积硅薄膜的固相晶化研究

本文用电化学腐蚀方法制备了多孔硅,并在多孔硅、石英、单晶硅片上用PECVD沉积了本征和P型硅膜,然后将硅膜分别用不同的温度和时间做固相晶化,借助Raman、SEM和XRD等手段对退火前后的硅薄膜微结构进行了分析研究。结果表明：单晶硅和多孔硅衬底上的非晶硅薄膜比石英衬底上的更容易晶化;具有硅晶格的衬底可以明显地起到种晶的作用,在一定条件下可以生长出晶格取向一致的硅膜。     

激光低温沉积金刚石膜

用ＸｅＣｌ紫外与ＣＯ２红外复合激光化学气相沉积方法，在３４０℃硅衬底上沉积成高纯金刚石膜。     

MPCVD法在氧化铝陶瓷上的金刚石膜沉积及其成核分析

用微波等离子体化学气相沉积（ＭＰＣＶＤ）法在氧化铝陶瓷基片上沉积了金刚石薄膜。实验表明，对基片进行适当的预处理，包括用金刚石研磨膏仔细研磨和沉积前原位沉积一层无定形碳层，可显著提高成核密度；对硅衬底和氧化铝基片上金刚石膜的成核过程进行了对比分析，并提出了提高氧化铝基片上沉积金刚石的成核的措施。     

DCPJ法多次沉积制备金刚石厚膜的研究

用直流电孤等离子体喷射法进行了多次沉积，在硅衬底上制备了金刚石厚膜，并用扫描电镜对这种厚膜的截面结构和表面状态进行分析，发现截面有明显的层状结构，在原来晶面上进行二次沉积是一个重新的成核过程。并对多次沉积过程中金刚石晶粒的生长特性进行了描述。     

基于硅过渡层纳米金刚石膜/GaN复合膜系的制备（英文）

本文研发了一种简便有效的在GaN半导体衬底上直接生长纳米金刚石膜的方法。研究发现,直接将GaN衬底暴露于氢等离子体中5 min即发生分解,且随着温度从560℃升高至680℃,这种分解反应愈加剧烈,很难在GaN衬底上直接形成结合力良好的纳米金刚石膜。通过在GaN衬底上镀制几纳米厚的硅过渡层,在富氢金刚石生长环境下,抑制了GaN衬底的分解,同时在GaN衬底上沉积了约2μm厚的纳米金刚石膜。硅过渡层厚度是决定纳米金刚石与GaN衬底结合力的主要因素。当硅过渡层厚度为10 nm时,纳米金刚石膜与GaN衬底呈现出大于10 N的结合力,可能与硅过渡层在金刚石生长过程中向SiC过渡层转变有关。     

Porous silicon capping by CVD diamond

In the last few years important research efforts were put concerning the optical properties of porous silicon (PS). Some interesting devices can be made using this new material (ex: L.E.D.s and micro cavities). However, a set of unsolved problems is keeping some distance between PS and its applications. Among these problems are the chemical instability and mechanical weakness.In this work, we attempted a CVD diamond protective layer deposition on PS. The optical properties of PS were preserved, as confirmed by photoluminescence (PL). The diamond film adhesion was checked by microhardness testing showing no crack propagation with a load of 200 gf. Nanoindentation measurements with 0.1 gf on the resulting surface showed a ten fold increase in hardness with respect to the uncoated material.     

Luminescent Properties of Porous Si Passivated by Diamond Film and DLC Film

Surface passivation methods for porous Si (PS) surfaces, i.e., depositing diamond film or diamond-like carbon (DLC) film on PS surfaces, were attempted. Two emission bands, weak blue band and strong red band existed in the PL spectrum of diamond film coated on PS, were discovered by the photoluminescence measurements. The luminescent mechanism and stability were discussed. The results indicated that diamond film may stabilize the PL wavelength and intensity of PS, and therefore could become a promising passivation film of porous Si. The PL properties of PS coated by DLC films, including hydrogenated diamond like carbon (DLC:H) film and nitrogen doped DLC film (DLC:N) were also studied in this paper. The DLC films may stabilize the PL of PS, but the photoluminescent intensity was obviously weaker than that of diamond film coated PS.     

光子热丝法沉积金刚石膜

采用一种改进的热丝CVD系统沉积金刚石膜,在传统热丝CVD腔中设置一套红外线发生器,中心波长3.5μm,处于氢与甲烷分子拉伸振动吸收峰位置。由于共振吸收能量使反应气体分解加强,在反应区获得较高浓度的原子氢和活性碳氢基团,使金刚石膜的生长速率和品质得到了提高。     

CVD金刚石厚膜的稀土化合物浆料刻蚀

与现有的金刚石膜势光工艺相匹配的高效刻蚀技术,是目前研究的热点,自行研制的稀土化合物浆料对CVD金刚石厚膜进行了刻蚀研究,刻蚀过程在低于金刚石氧化点的温度下和大气环境中完成,其刻蚀结果,用扫描电子显微镜给出。实验表明,该工艺采用廉价的稀土化合物为原料,具有简单、完全、高效的特点。     

化学气相沉积金刚石薄膜生长的原位反射率测量

报道了化学气相沉积金刚石薄膜生长的原位反射率测量,提出了监控金刚石薄膜生长的激光反射多光束干涉的数学模型。通过原位反射率的测量,精确监控了金刚石薄膜的生长厚度,成功地制备了红外增透增,这种方法的测量装置简单、紧凑而且可靠。     

CVD金刚石膜的场发射机制

利用热灯丝化学气相沉积方法在光滑的钼上沉积了金刚石膜,用扫描电子显微镜和Raman谱对金刚石膜进行了分析。结果表明金刚石膜是由许多金刚石晶粒组成,晶粒间界主要是石墨相,并且在膜内有许多缺陷。金刚石膜的场发射结果表明高浓度CH4形成的金刚石膜场发射阈位电场较低浓度CH4形成的金刚石为低。这意味着杂质（如石墨）和缺陷（悬挂键）极大地影响了膜的场发射性能。根据以上结果,提出了一种CVD金刚石膜的场发射机制即膜内的缺陷增强膜内的电场,石墨增大电子的隧穿系数以增强CVD金刚石膜的场发射。     

Frontiers in HWCVD

The research effort in the field of Hot Wire CVD (also called Catalytic CVD or initiated CVD) has increased considerably over the last 10 years. An increasing variety of thin film materials can be obtained with this method, with good feedstock utilization and high deposition rate. The properties of the deposited films are notably different from those of films made with conventional methods. A number of applications, such as diamond deposition, functional polymer deposition, and passivating silicon nitride deposition, have already found its way to commercial manufacturing. In this paper we discuss some of the modern research issues in the realm of Hot Wire CVD (Cat-CVD) and i-CVD.     

多孔硅与聚甲基丙烯酸甲酯复合光致发光特性研究

多孔硅与有机材料复合可以改善多孔硅的光致发光特性。用化学腐蚀的方法制备了多孔硅，通过不同方法实现了多孔硅与聚甲基丙烯酸甲酯(PMMA)的复合。实验结果表明，用旋涂法实现的PMMA固化后再与多孔硅复合而制得的样品的结果最好，它与原始的多孔硅样品相比，发光峰发生了蓝移而且发光强度下降很小。PMMA层有限的厚度和PMMA对多孔硅表面的保护使复合后发光强度下降很小。制备的多孔／PMMA复合体系的发光强度几乎不随时间而下降，这可能是由于PMMA有效地隔绝多孔硅与空气的接触，保护了多孔硅的表面，不会产生更多的悬挂键。     

Machining of Hypereutectic Al-Si Alloy with CVD Diamond Coated Si4N4. Inserts

Due to its excellent mechanical properties, diamond can be used for many applications in mechanical engineering. With the help of the Chemical Vapor Deposition (CVD) method it is possible to deposit polycrystalline diamond films on different substrate materials of nearly any shape and surface. So diamond cutting tools with complex geometry are now possible. In this investigation diamond coatings deposited by microwave plasma CVD (MW-PACVD) on Si₃N₄ inserts were used for turning experiments. By means of changes in the CH₄/H₂ gas ratio two different types of film morphology were generated, one rather highly faceted and the other one fine-grained ballas-type surface microstructure. The cutting performance of the CVD diamond coated triangular silicon nitride inserts was analyzed for continuous dry turning of the hypereutectic AISi 17Cu4Mg alloy with different cutting speeds. During the experiments no wear of the diamond films could be detected; nevertheless, the adhesion to the Si₃N₄ substrate has still to be improved. The results of the cutting tests gave valuable information for favorable geometry and clamping devices of cutting tools coated with CVD diamond and for suitable machining parameters.     

An assessment of radiotherapy dosimeters based on CVD grown diamond

Diamond is potentially a very suitable material for use as a dosimeter for radiotherapy. Its radiation hardness, the near tissue equivalence and chemical inertness are some of the characteristics of diamond, which make it well suited for its application as a dosimeter. Recent advances in the synthesis of diamond by chemical vapour deposition (CVD) technology have resulted in the improvement in the quality of material and increased its suitability for radiotherapy applications. We report in this paper, the response of prototype dosimeters based on two different types (CVD1 and CVD2) of CVD diamond to X-rays. The diamond devices were assessed for sensitivity, dependence of response on dose and dose rate, and compared with a Scanditronix silicon photon diode and a PTW natural diamond dosimeter. The diamond devices of CVD1 type showed an initial increase in response with dose, which saturates after ≈6 Gy. The diamond devices of CVD2 type had a response at low fields (<1162.8 V/cm) that was linear with dose and dose rate. At high fields (>1162.8 V/cm), the CVD2-type devices showed polarisation and dose-rate dependence. The sensitivity of the CVD diamond devices varied between 82 and 1300 nC/Gy depending upon the sample type and the applied voltage. The sensitivity of CVD diamond devices was significantly higher than that of natural diamond and silicon dosimeters. The results suggest that CVD diamond devices can be fabricated for successful use in radiotherapy applications.