室温下单晶硅压痕微裂纹的形成与扩展

用透射电镜定位观察研究了在室温下高纯单晶硅显微压痕表面radial脆性微裂纹的纳观形变 ,阐述了塑性变形对微裂纹形核、扩展及开裂的影响。发现 :室温下单晶硅的压痕前沿经历了极复杂的非线性演化 :前沿区的位错发射与运动 (Kcleave>Kemit时 )、解理微纹形核与扩展 (σ塞 >σth 时 )。观察到压痕前沿发生塑性诱导解理和解理胚不连续形核与扩展的过程     

单晶硅硬度压痕裂纹的特征

单晶硅硬度压痕裂纹的特征蔡传荣张琼（福州大学，福州３５０００２）单晶硅是电脑、光纤通信等重要材料，其表面受接触载符作用而容易损伤、产生裂纹直至破碎。为工程设计选材需要，国内外学者对其接触损伤有过研究［１］［２］，本文用扫描电镜观察单晶硅显微硬度压痕裂...     

压痕诱发单晶硅非晶化相变的透射电镜观察

晶体硅在高压下会发生相变［１］。显微压痕实验能够产生极大的压强（ＧＰａ级），有可能诱发硅的相变［２］。Ｃｌａｒｋｅ等人首次利用透射电子显微镜（ＴＥＭ）在微观尺度上给出了单晶硅上维氏显微压痕的平视形貌像（ｐｌａｎ－ｖｉｅｗ）［３］，指出压痕中心已经发生...     

聚丙烯酸微球自组装形态的透射电镜观察

本文以无皂乳液聚合法制备的聚丙烯酸微球乳液为例,介绍了一种新的透射电镜样品的制样方法.即直接将粘稠状乳液滴在铜网上,随即刮去多余的大部分乳液从而在铜网上形成极薄的连续膜或间断膜.采用这种制样方法,无需对乳液进行稀释,即可得到适用于TEM观察的样品.利用TEM直观地观察到了聚丙烯酸微球紧密排列的单层膜和球表面存在包裹物的结构,分析了包裹物的元素组成.此外,还观察到了聚丙烯酸微球紧密排列的自组装双层膜和多层膜的形态.     

32磷-玻璃微球治疗裸鼠人肝癌移植瘤的透射电镜观察

32磷-玻璃微球(32P-GMS)是一种新型的放射性抗癌微球制剂[1].目前,应用放射性微球治疗肝癌已受到了极大重视,但是关于32P-GMS局部注射给药治疗实验性肝癌的研究甚少,超微结构研究尚未见报道[2-4].为此,我们建立了裸鼠人肝癌移植瘤模型进行电镜观察.     

单晶硅材料补偿度的确定

本文叙述了ｐ型及ｎ型硅材料杂质补偿度确定的各种方法，并评述了各种方法的实验条件及其优缺点，还指出了目前我国各单位采取的简单而较可靠的方法。     

ZrO2薄膜横断截面的透射电镜观察

本文报道了ZrO2薄膜横断截面的透射电镜观察结果。ZrO2薄膜通过射频磁控溅射法制备，电镜观察表明，薄膜致密均匀，呈柱状晶生长，通过电子衍射和X光衍射实验确定。为面心立方多晶膜，此外，通过对高分辨电子显微象的观察与分析，对薄膜的形成机理进行了初步探讨。     

基于单晶硅梁的静电RF MEMS开关

RFMEMS开关是低功耗、低损耗高频通讯电路和系统的关键部件,静电驱动RFMEMS开关因具有零直流功耗、开关时间短、结构简单、易集成的优点而成为研究热点,但是驱动电压高、薄膜应力变形严重、寿命短等问题制约了其发展,提出了一种基于单晶硅梁的推拉式静电RFMEMS开关结构,能够解决静电RFMEMS现有的缺陷。     

硅中缺陷的透射电镜观察

随着集成电路制造工艺技术的不断进步,器件线宽不断减小,硅材料中缺陷的危害越来越不可忽视.通过TEM观察了硅中氧沉积、工艺诱生缺陷等并对之进行了分析.     

Polishing behaviors of single crystalline ceria abrasives on silicon dioxide and silicon nitride CMP

The effects of single crystalline ceria (CeO₂) abrasives in chemical mechanical polishing (CMP) slurries were investigated for silicon dioxide (SiO₂) and silicon nitride (Si₃N₄) CMP process. The size of ceria abrasives was controlled by varying hydrothermal reaction conditions. Polishing removal rate was measured with four slurries, with different mean primary particle size of 62, 116, 163 and 232 nm. The polishing results showed that the single crystalline ceria abrasives were not easily broken-down by mechanical force during CMP process. It was found that the removal rate of oxide and nitride film strongly depend upon abrasive size, whereas the surface uniformity deteriorates as abrasive size increases. The observed polishing results confirmed that there exists an optimum abrasive size (163 nm) for maximum removal selectivity between oxide and nitride films. The polishing behavior of the single crystalline ceria abrasives was discussed in terms of morphological properties of the abrasive particle.     

扩散温度和时间对晶体硅太阳电池性能的影响

研究了薄层方块电阻对单晶硅太阳电池的开路电压(Voc)、短路电流(Isc)、填充因子(FF)和转换效率(η)的影响。通过控制扩散温度和时间制备了具有不同薄层方块电阻的单晶硅太阳电池。结果表明:当扩散温度和时间分别为863℃和1 050 s时,电池性能得到了有效的改善,其平均开路电压、短路电流、填充因子和转换效率分别为0.64 V,5.58 A,0.755和17.3%。     

直拉硅中氧沉淀的TEM研究

论述了使用透射电镜来研究氧沉淀的形态与热处理温度和时间的关系.对氧沉淀的生成动力学,研究的现状和存在的问题以及发展前景也进行了讨论.     

Nanoindentation-induced phase transformation in crystalline silicon and relaxed amorphous silicon

Nanoindentation-induced phase transformation in both crystalline silicon (c-Si) and relaxed amorphous silicon (a-Si) have been studied. A series of nanoindentations were made with a sharp diamond Berkovich tip. During nanoindentations, maximum loads were applied from 1000 to 6000 μN, with a 1000 μN/s loading rate. A slow unloading rate at 100 μN/s was chosen to favor the formation of the high-pressure polycrystalline phases (Si-III and Si-XII). A fast unloading rate within 1 s was used to obtain a-Si end phase. The nanoindentation behavior and the structure of deformation regions were examined by load–depth characteristics curves and Raman. Large differences were observed between the transformation behavior in c-Si and that in relaxed a-Si. Indentation curves in c-Si present plastic deformation curves with elbow (no pop-out) on the unloading curves, even for loads up to 9000 μN. On the other hand, indentations in relaxed a-Si give rise to the same plastic deformation as c-Si at low loads (1000–2000 μN), whereas show clear pop-outs at high loads (above 3000 μN). Raman results suggest that high-pressure phases (HPPs) can occur more easily within a relaxed a-Si matrix than in a c-Si matrix. The results suggest a significantly different indentation behavior and phase transformation sequence in c-Si and relaxed a-Si at the nanoscale.     

Passivation of p-n junction in crystalline silicon by amorphous silicon

Hydrogenated amorphous silicon, a-Si:H, is shown to be an excellent passivant for crystalline silicon (c-Si) p-n junctions. A two-orders-of-magnitude reduction in reverse leakage current from that of a typical thermal oxide passivated junction is obtained. This is achieved through a lowering of the interface state density by hydrogenation of the c-Si surface. Superior bias-temperature stability of the passivated junctions also is observed. There is evidence that the hydrogen in the bulk of the a-Si:H can act as a hydrogen reservoir for rehydrogenation of the interface between c-Si and a-Si:H. Thermal stability of the a-Si:H is adequate for temperatures up to 500°C for 30 min, which is sufficient for most device-processing requirements. Above 550°C, significant dehydrogenation from both the interface and the bulk a-Si:H regions and an increase in leakage are observed. The passivation properties were assessed through studies of the current-voltage and current-temperature characteristics of the p-n junctions.     

前结背接触晶硅太阳电池发射区研究

利用Silvaco-TCAD仿真软件全面系统地分析了发射区表面浓度(cE)、结深(xj)及发射区覆盖比率(EF)对P型前结背接触晶硅太阳电池输出特性的影响。结果表明:基于常规低成本P型晶硅衬底(利用直拉法生长,电阻率为1.5?·cm,少子寿命为10μs)的前结背接触太阳电池,其上表面发射区表面浓度及结深对太阳电池的输出特性产生显著影响。上表面发射区表面浓度和结深越大,短波入射光外量子效率越小。当上表面发射区表面浓度为1×1019 cm–3,结深为0.2μm时,电池效率高达20.72%。侧面和下表面发射区表面浓度及结深对太阳电池输出特性的影响较小。但侧面和下表面发射区覆盖比率对太阳电池的输出特性产生显著影响。侧面和下表面发射区覆盖比率越大,太阳电池外量子效率和转换效率越高。     

Shunt types in crystalline silicon solar cells

Nine different types of shunt have been found in state‐of‐the‐art mono‐ and multicrystalline solar cells by lock‐in thermography and identified by SEM investigation (including EBIC), TEM and EDX. These shunts differ by the type of their I–V characteristics (linear or nonlinear) and by their physical origin. Six shunt types are process‐induced, and three are caused by grown‐in defects of the material. The most important process‐induced shunts are residues of the emitter at the edge of the cells, cracks, recombination sites at the cell edge, Schottky‐type shunts below grid lines, scratches, and aluminum particles at the surface. The material‐induced shunts are strong recombination sites at grown‐in defects (e.g., metal‐decorated small‐angle grain boundaries), grown‐in macroscopic Si₃N₄ inclusions, and inversion layers caused by microscopic SiC precipitates on grain boundaries crossing the wafer. Copyright © 2004 John Wiley & Sons, Ltd.     

Porous silicon in crystalline silicon solar cells: a review and the effect on the internal quantum efficiency

Crystalline silicon (c-Si) is the dominant semiconductor material in use for terrestrial photovoltaic cells and a clear tendency towards thinner, active cell structures and simplified processing schemes is observable within contemporary c-Si photovoltaic research. The potential applications of porous silicon and related benefits are reviewed. Specific attention is given to the different porous silicon formation processes, the use of this porous material as anti-reflection coating in simplified processing schemes and for simple selective emitter processes and its light trapping and surface passivating capabilities, which are required for advantageous use in thin active cell structures. Our analysis of internal quantum efficiency data obtained on both conventional and thin-film c-Si solar cells has been performed with the aim of describing the light diffusing behaviour of porous Si as well as investigating the surface passivating capabilities. An effective entrance angle of 60° is derived, which corresponds to totally diffuse isotropic light, and the importance of a correction for absorption losses in the porous layer is illustrated. Furthermore, photoconductivity decay measurements of freshly etched porous Si on float-zone p-type Si indicate a strong bias-light dependency and a fast degradation of the surface recombination velocity. © 1998 John Wiley & Sons, Ltd.     

碳化硅晶须抗氧化性能的TEM研究

碳化硅是最好的晶须材料之一,在用碳热还原法合成碳化硅纳米晶须时,原料中碳往往过量10wt.%左右。碳过量有利于碳化硅纳米晶须的形成和产率的提高,过量的碳一般采用在空气中高温氧化的方法除去。碳化硅纳米晶须抗氧化性能的好坏,直接影响到脱碳温度和时间的选择,以达到既除去样品中的碳又防止碳化硅纳米晶须大量氧化的目的。本文利用透射电子显微镜对碳化硅纳米晶须的抗氧化性能进行了初步研究。图1是未经空气中氧化的碳化硅纳米晶须的TEM照片,从图中可看出碳化硅纳米晶须的表面光滑,无SiO2包覆层。图2a是在500℃下恒温2h得到的碳化硅纳米…