LPCVD氮化硅薄膜的化学组成

分别采用X光电子能谱(XPS)、俄歇电子能谱(AES)、傅立叶红外光谱(FTIR)以及弹性反冲探测(ERD)等方法,分析了三氯硅烷-氨气-氮气体系低压化学气相沉积(LPCVD)氮化硅(SiNx)薄膜的化学组成,并利用原子力显微镜(AFM)观察了SiNx薄膜的表面形貌.XPS分析结果表明,当原料气中氨气与三氯硅烷的流量之比小于3时获得富Si的SiNx薄膜,当流量之比大于4时获得近化学计量的SiNx薄膜(x=1.33).AES深度分析与XPS分析结果很好地吻合,在835cm-1产生的强红外吸收峰表明Si-N键的形成,ERD分析表明所制备SiNx薄膜中的氢含量很低(1.2at.%).AFM分析结果表明,所沉积的SiNx薄膜均匀、平整,薄膜的均方根粗糙度RMS仅为0.47nm.     

利用ISSG退火技术实现沉积二氧化硅薄膜平坦化

利用现场水汽生成(in-situ steam generation,ISSG)退火这种新型的低压快速氧化热退火技术,在对沉积二氧化硅薄膜热退火的同时进行补偿氧化生长,最终实现了沉积二氧化硅薄膜的平坦化.实验数据表明,ISSG退火补偿生长后整个晶圆表面的薄膜厚度波动(最大值与最小值之差)从0.76nm降到了0.16nm,49点厚度值的标准偏差从0.25nm降到了0.04nm.同时,薄膜的隧穿场强增加到4.3MV/cm,硅氧界面与传统的氧气快速退火工艺相比更为良好.实验结果为二氧化硅薄膜平坦化提供了新的思路,对实际生产具有重要意义.     

高效率硅太阳电池AR-BSF一次成型工艺研究

本文描述一种用LPCVD方法淀积Si3N4形成太阳电池减反射膜(AR)同时又制得高效率硅太阳电池铝合金高低结背面场(BSF)的新工艺。该工艺不仅简化了太阳电池的制作过程,即电池的AR和BSY一次形成,而且由于系统处于高真空,电池处在N2和H2的气氛中,所以改善了太阳电池发射区的表面特性。实验结果表明:为获得较好的电池性能,在完成电池的AR和BSF时,厚的铝膜,较高的淀积Si3N4温度以及在电池发射区表面生长80100的SiO2层是必要的。     

低压化学汽相淀积含氢氮化硼薄膜

本实验采用二硼烷(B_1H_6)和氨气(NH_(?)),在388～700℃下进行低压化学汽相淀积生成含有硼、氮、氢的膜(B_(1～3)NH),用于X光曝光掩模的基底.已测得膜的各种特性如淀积速率、电阻率、元素成份比、晶型、折射率、红外吸收光谱、应力变化、对光的透射率、化学不活泼性及等离子腐蚀速率等.     

Si(111) 衬底上3C-SiC的超低压低温外延生长

研究了发展一种Si衬底上低温外延生长3C－SiC的方法。采用LPCVD生长系统，以SiH4和C2H4为气源，在超低压（30Pa) ,低温（900℃）的条件下，在Si(111衬底上外延生长出高质量的3C－SiC薄膜材料。采用俄歇能谱（AES），X射线衍射（XRD）和原子力显微镜（AFM）等分析手段研究了SiC薄膜的外延层组分，晶体结构及其表面形貌。AES结果表明薄膜中的Si/C的原子比例符合SiC的理想化学计量比，XRD结果显示了3C－SiC外延薄膜的良好晶体结构，AFM揭示了3C－SiC薄膜的良好的表面形貌。     

Equipment modelling of CVD and etching

This paper presents results of equipment simulation giving applications of the fluid-dynamic solution to three commonly used reactors in the semiconductor industry — Tungsten CVD, Aluminum plasma etching, and Poly LPCVD. The results obtained include the determination of three-dimensional profiles for pressure, temperature, velocity, concentration of different chemical species, etch rates, deposition rates and uniformity over the wafer. This simulation technique is an important tool for equipment and process optimization by both the equipment suppliers and process engineers, because it allows a better visualization of the variables that control the process and allows a fast estimation of how changes on the process parameters or hardware configuration influence the results.     

Si(001)衬底上方形3 C-SiC岛的LPCVD生长

Si衬底上SiC的异质外延生长深受关注,为了了解Si衬底上的成核及长大过程,采用PLCVD方法在Si(001)衬底上生长出了方形3C-SiC岛,利用Nomarski光学显微镜和扫描电子显微镜（SEM）观察了SiC岛的形状,尺寸,密度和界面形貌,结果表明,3C－SiC岛生长所需的Si原子来自反应气源,衬底上的Si原子不发生迁移或外扩散,气相中C原子浓度决定了SiC岛的生长过程。     

The effect of low pressure chemical vapor deposition of silicon nitride on the electronic interface properties of oxidized silicon wafers

The effect of LPCVD Si₃N₄ film deposition on oxidized Si wafers, to form Si₃N₄/SiO₂/Si stacks, is studied using capacitance–voltage and carrier lifetime measurements. The deposition of a nitride film leads to an increase in the density of defects at the Si–SiO₂ interface, with the increase being greater the thinner the oxide. However, even the presence of a very thin intermediate oxide results in a dramatic improvement in interface properties compared to the direct deposition of the Si₃N₄ film on Si. The interface degradation occurs in the initial stages of nitride film deposition and appears to be largely the result of increased interfacial stress. Subsequent thermal treatments do not result in significant further degradation of the Si–SiO₂ interface (except for a loss of hydrogen), again in contrast to the case where the nitride films is deposited onto Si. Copyright © 2007 John Wiley & Sons, Ltd.     

Mechanistic investigation of aluminide coating formation by low-pressure chemical vapor deposition method on NiCoCrAlY coating in presence of nickel-ceria composite layer

In this study, a hybrid coating comprised of NiCoCrAlY fabricated by HVOF method, Ni–CeO₂ composite coated by electrodeposition, and aluminide coating applied by low pressure chemical vapor deposition (LPCVD) method are investigated. To elucidate the formation process of aluminide coating, the microstructure and properties of the applied coatings were examined by field emission scanning electron microscopy (FESEM), X-ray diffraction (XRD), and EDS analyses. It was concluded that the desired β-NiAl phases are uniformly created within a single step on the surface. Furthermore, with the extending of the coating duration from 2 to 4 h, the thickness of the aluminide coating was increased from 14 to 25 μm. The thickness values were increased even further in the presence of Ni–CeO₂ coating, where the growth mechanism was also changed. Within 4 h, a coating with a thickness of roughly 50 μm was obtained. Moreover, in the presence of Ni–CeO₂ coating, it was observed that the inward diffusion of aluminum was predominant at the beginning of the process, whereas with longer processing durations, the outward diffusion of the nickel becomes dominant instead.