太阳能晶硅片切割废液资源化回收处理工艺研究

采用纯物理法,通过固液分离、脱色、精滤、真空蒸馏、指标调节等工艺技术,对太阳能晶硅片切割废液进行资源化回收处理,切割废液回收得到的产品各项性能指标满足使用要求,可以再次作为太阳能晶硅片切割液使用,实现切割废液资源化循环利用,以及社会、环境和经济效益的有机统一和协调发展。

偏晶向(111)硅片闪耀光栅的设计

利用硅单晶的特殊结构可以设计出不同角度的闪耀光栅,再使用MEMS的紫外光刻、各向异性腐蚀等常规工艺就可以完成硅闪耀光栅的制作。设计了一种利用偏转晶向(111)硅片制作小角度闪耀光栅的方法,避免了利用其它晶向的硅片制作闪耀光栅的缺点。利用这种方法制作了线宽为4μm的硅闪耀光栅,使用原子力显微镜(AFM)进行了光栅表面形貌测试,得到平均表面粗糙度为110.94nm,试验结果表明制作的硅光栅样片具有良好光学特性的反射表面和光栅槽形。

碱腐蚀减薄硅片过程中少子寿命性质研究

通过高频光电导法研究了超薄晶硅片少数载流子寿命的变化规律,分析了碱液腐蚀速率、表面缺陷态的变化对少子寿命的影响,得到:在现有的切片工艺条件下,腐蚀10分钟即可将表面损伤层完全去除,使超薄晶片显示出体内和表面寿命共同决定的较大少子寿命值.

晶片边缘磨削控制方法研究

对半导体工艺中晶片的边缘磨削技术进行了论述,分析了晶片边缘磨削技术的特点,在此基础上,提出了一种高效、可靠的晶片边缘磨削方法。该方法基于单轴电机进给控制,通过控制软件来实现对晶片边缘及定位边的磨削。首先确定晶片定位边位置,然后通过精确控制承片台驱动电机的旋转角度来磨削晶片圆边,对于定位边的磨削,需要精确控制承片台驱动电机的旋转角度和进给电机的进给量,通过两电机联动控制,完成定位边磨削。该方法控制精度高,成功实现了在单轴电机驱动下的晶片圆边及定位边磨削。试验结果证明,该方法可靠、稳定、高效,并降低了设备硬件成本。

Nanogrinding of SiC wafers with high flatness and low subsurface damage

Nanogrinding of SiC wafers with high flatness and low subsurface damage was proposed and nanogrinding experiments were carried out on an ultra precision grinding machine with fine diamond wheels. Experimental results show that nanogrinding can produce flatness less than 1.0μm and a surface roughness Ra of 0.42nm. It is found that nanogrinding is capable of producing much flatter SiC wafers with a lower damage than double side lapping and mechanical polishing in much less time and it can replace double side lapping and mechanical polishing and reduce the removal amount of chemical mechanical polishing.

Effect of Nano-sized CeO_2 Abrasives on Chemical Mechanical Polishing of Silicon Wafer

The conception of the soft layer during chemical mechanical polishing(CMP) was proposed for the first time. The soft layer was a reaction layer formed on the silicon surface; it was softer than the silicon substrate and its thickness was about several nanometers. The existence of the soft layer could increase the material volume removed by one particle and increase the material removal rate during CMP. At the same time, the soft layer could decrease the cutting depth of the abrasive particle so as to realize ductile grinding, and it is useful to decrease the roughness of the polished surface and to improve the polishing quality.

Investigation on Silicon Thin Film Solar Cells

The preparation, current status and trends are investigated for silicon thin film solar cells. The advantages and disadvantages of amorphous silicon thin film, polycrystalline silicon thin film and mono-crystalline silicon thin film solar cells are compared. The future development trends are pointed out. It is found that polycrystalline silicon thin film solar cells will be more promising for application with great potential.

Analysis on Conductivity of nc-Si: H Films

A conduction channel model is proposed to explain the high conductivity property of nc-Si: H. Detailed energy band diagram is developed based on the analysis and calculation, and the conductivity of the nc-Si: H was then analysed on the basis of energy band theory. It is assumed that the conductivity of the nc-Si: H stems from two parts: the conductance of the interface, where the transport mechanism is identified as a thermal-assisted tunnelling process, and the conductance along the channel around the grain, which mainly determined the high conductivity of the nc -Si: H. The conductivity of nc - Si: H is calculated and compared with the experiment data. The theory is in agreement with the experiment.

Effects of thermal transport properties on temperature distribution within silicon wafer

A combined conduction and radiation heat transfer model was used to simulate the heat transfer within wafer and investigate the effect of thermal transport properties on temperature non-uniformity within wafer surface. It is found that the increased conductivities in both doped and undoped regions help reduce the temperature difference across the wafer surface. However, the doped layer conductivity has little effect on the overall temperature distribution and difference. The temperature level and difference on the top surface drop suddenly when absorption coefficient changes from 104 to 103 m-1. When the absorption coefficient is less or equal to 103 m-1, the temperature level and difference do not change much. The emissivity has the dominant effect on the top surface temperature level and difference. Higher surface emissivity can easily increase the temperature level of the wafer surface. After using the improved property data, the overall temperature level reduces by about 200 K from the basis case. The results will help improve the current understanding of the energy transport in the rapid thermal processing and the wafer temperature monitor and control level.

Analysis of the application of the laser equipment in the production line of the amorphous silicon film solar cells

The laser equipment is one of the key equipment in the production line of the solar energy. In this article, the author de-scribes the application of the laser equipment in the production line of the amorphous silicon film solar cells, and points out that the stable and exactitude is the key direction of the future development of the laser scribing equipment.

彭小峰：超越光速?

相信许多人包括信息最灵通的媒体，在2007年以前很少或者根本就没有听说过江西赛维LDK的名字，不过那时的施正荣等太阳能哥们已经见识了这个32岁的年轻掌门——彭小峰。

Effect of triple-phase contact line on contact angle hysteresis

Recent studies have shown that the triple-phase contact line has critical effect on the contact angle hysteresis of surfaces.In this study,patterned surfaces with various surface structures of different area fractions were prepared by electron etching on a silicon wafer.The advancing angle,receding angle and hysteresis angle of these surfaces were measured.Our experimental results showed that while the geometry of microstructure and contact line have a minor effect on the advancing angle,they have a significant effect on the receding angle and thus the hysteresis angle.We have shown that the effect of microstructure and the contact line can be described by a quantitative parameter termed the triple-phase line ratio.The theoretical predictions were in good agreement with our experimental results.

Design of terahertz band-stop filter based on a metallic resonator on high-resistivity silicon wafer

In this paper, we present a terahertz (THz) band-stop filter realized by fabricating a metallic T-shaped resonator pattern on the high-resistivity silicon wafer. The filter exhibits two typical band-stop response characteristics depending on the incident direction of electric field with respect to the T-shaped resonator. When the long and the short arms of the T-shaped resonator were electrically polarized by changing the incident THz wave transmission directions, the corresponding central frequencies of the band-stop filter were found to be 0.436 THz at 42dB and 0.610 THz at 28 dB, respectively. Using three-dimensional (3D) finite-integral time-domain simulations, the band-stop filter was designed, which can operate in the wavelength between 0.2 and 0.8 THz. Experimental verification was also performed using a free space THz time-domain spectroscopy system. The band-stop response characteristics are in good agreement with the simulation results. The interesting THz band-stop filtering properties suggest a promising application in the modern THz communication systems, THz time-domain spectroscopic imaging and THz continuous wave imaging.

120 mm Single-crystalline perovskite and wafers： towards viable applications

As the large single-crystalline silicon wafers have revolutionized many industries including electronics and solar cells, it is envisioned that the availability of large single-crystalline perovskite crystals and wafers will revolutionize its broad applications in photovoltaics, optoelectronics, lasers, photodetectors, light emitting diodes(LEDs), etc. Here we report a method to grow large single-crystalline perovskites including single-halide crystals: CH3NH3PbX3(X=I, Br, Cl), and dual-halide ones:CH3NH3Pb(ClxBr1.x)3 and CH3NH3Pb(BrxI1.x)3, with the largest crystal being 120 mm in length. Meanwhile, we have advanced a process to slice the large perovskite crystals into thin wafers. It is found that the wafers exhibit remarkable features:(1)its trap-state density is a million times smaller than that in the microcrystalline perovskite thin films(MPTF);(2) its carrier mobility is 410 times higher than its most popular organic counterpart P3HT;(3) its optical absorption is expanded to as high as910 nm comparing to 797 nm for the MPTF;(4) while MPTF decomposes at 150 °C, the wafer is stable at high temperature up to270 °C;(5) when exposed to high humidity(75% RH), MPTF decomposes in 5 h while the wafer shows no change for overnight;(6) its photocurrent response is 250 times higher than its MPTF counterpart. A few electronic devices have been fabricated using the crystalline wafers. Among them, the Hall test gives low carrier concentration with high mobility. The trap-state density is measured much lower than common semiconductors. Moreover, the large SC-wafer is found particularly useful for mass production of integrated circuits. By adjusting the halide composition, both the optical absorption and the light emission can be fine-tuned across the entire visible spectrum from 400 nm to 800 nm. It is envisioned that a range of visible lasers and LEDs may be developed using the dual-halide perovskites. With fewer trap states, high mobility, broader absorption, and humidity resistance, it is expected that solar cells with high stable efficiency maybe attainable using the crystalline wafers.