共查询到20条相似文献,搜索用时 464 毫秒
1.
利用新改进的垂直低压热壁CVD 设备,应用TCS 和C2H4 分别作为Si 源和C 源,在偏8°晶向的4H-SiC 衬底上生长出了高质量的外延膜。当生长温度在1500℃到1530℃之间时,生长速率达到了25-30μm/h。50μm 厚的外延膜(生长2 小时)的结晶质量和表面粗糙度和薄的外延膜(生长30 分钟)相比均没有发生恶化。外延膜的背景掺杂浓度下降到了2.13×1015cm-3。另外,本文还研究了C/Si 对生长速率和外延膜结晶质量的影响。 相似文献
2.
外延侧向附晶生长(ELO)技术是在单晶硅上面的氧化岛的边缘引晶并在氧化层上附晶生长CVD硅来形成SOI层; ELO技术用常规的外延反应炉来生长外延硅;与别的SOI方法相比,这种SOI膜的缺陷密度低而且支承ELO硅的片子不发生曲翘变形;SOI/ELO膜的电学特性,诸如迁移率和寿命,与在同样反应炉中生长的同质外延层的电学特性类似;文中讨论了与ELO和选择外延生长(SEG)相关的问题;我们将介绍缺陷结构、生长速率与图形几何尺寸的关系和附晶生长速率方面的现况,我们还将讨论ELO/SEG膜的电学特性,特别是(用CVD附晶生长形成的)SiO_2/Si界面特性;文中将描述获得在硅膜下有连续氧化层的SOI膜所用的工艺,还将讨论制备这些薄层的潜力和所面临的问题。 相似文献
3.
H2对UHV/CVD低温选择性外延生长Si1-xGex的影响 总被引:1,自引:0,他引:1
利用超高真空化学气相沉积(UHV/CVD)成功实现了Si1-xGex的低温选择性外延生长,并研究了H2对选择性外延生长的影响及其作用机理.以SiH4和GeH4为反应气源,在开有6mm×6mm窗口氧化硅片上进行Si1-xGex外延层的生长.首先分别以不含H2(纯GeH4)和含H2(90%H2稀释的GeH4)的两种Ge源进行选择性外延生长.通过SEM观察两种情况下氧化硅片表面,发现H2的存在对选择性外延生长有至关重要的作用.接着以90%H2稀释的GeH4为Ge源,变化Si源和Ge源的流量比改变H2分压,以获得SiH4和GeH4(90%H2)的最佳流量比,使外延生长的选择性达到最好.利用SEM观察在不同流量比时,经40min外延生长后各样品的表面形貌,并对其进行比较,分析了H2分压在Si1-xGex选择性外延生长中的作用机理. 相似文献
4.
5.
利用超高真空化学气相沉积(UHV/CVD)成功实现了Si1-xGex的低温选择性外延生长,并研究了H2对选择性外延生长的影响及其作用机理.以SiH4和GeH4为反应气源,在开有6mm×6mm窗口氧化硅片上进行Si1-xGex外延层的生长.首先分别以不含H2(纯GeH4)和含H2(90%H2稀释的GeH4)的两种Ge源进行选择性外延生长.通过SEM观察两种情况下氧化硅片表面,发现H2的存在对选择性外延生长有至关重要的作用.接着以90%H2稀释的GeH4为Ge源,变化Si源和Ge源的流量比改变H2分压,以获得SiH4和GeH4(90%H2)的最佳流量比,使外延生长的选择性达到最好.利用SEM观察在不同流量比时,经40min外延生长后各样品的表面形貌,并对其进行比较,分析了H2分压在Si1-xGex选择性外延生长中的作用机理. 相似文献
6.
7.
8.
9.
在特定温控下对掺杂气体分子的状态和活性进行控制 ,建立了一套具有自主知识产权的气源分子束外延工艺生长 Si Ge/Si材料的原位掺杂控制技术。采用该技术生长的 Si Ge/Si HBT外延材料 ,可将硼杂质较好地限制在 Si Ge合金基区内 ,并能有效地提高磷烷对 N型掺杂的浓度和外延硅层的生长速率 ,获得了理想 N、P型杂质分布的 Si Ge/Si HBT外延材料 相似文献
10.
形成SOI结构的ELO技术研究 总被引:1,自引:0,他引:1
本文研究了在常压外延系统中,利用 SiCl_4/H_2/Br_2体系在SiO_2上外延横向生长(ELO)单晶硅技术.比较了Br_2和HCl对硅的腐蚀速率,发现前者对娃的腐蚀速率约比后者慢一个数量级,指出Br_2的引入有着重要意义.给出了Br_2和H_2对Si和SiO_2的腐蚀速率曲线,讨论了外延横向生长速率对SOI结构的材料表面形貌的影响.在该 SOI膜上制造了 MOS/SOI器件,其N沟最大电子迁移率为360cm~2/V.s(沟道掺杂浓度为 1×10~(16)/cm~3),源-漏截止电流为 9.4×10~(-10)A/μm. 相似文献
11.
The segregation of Sb in Si layers grown by molecular beam epitaxy on Si substrates with the (111), (110), and (115) crystallographic orientations is studied; the results obtained for these orientations are compared with those obtained for the most widely used orientation (001). It is found that there is a qualitative similarity between the temperature dependences of the Sb segregation ratio (r) for all studied orientations; in particular, it is possible to separate two characteristic temperature ranges corresponding to the kinetically limited and equilibrium regimes of segregation. However, quantitatively, the values of r for the orientations under study differ significantly from those for the Si(001) case at the same temperatures. For all orientations, narrow temperature ranges within which the values of r vary by nearly five orders of magnitude are revealed for all dependences of r on the growth temperature. This finding allows us to adopt the method of selective doping, which was for the first time suggested by us for structures grown on Si (001) and is based on the controlled use of the segregation effect, to structures grown on Si substrates with an orientation different from (001). Using this method, selectively doped Si:Sb/Si(111) structures are fabricated; in these structures, a variation in the Sb concentration by an order of magnitude occurs at the scale of several nanometers. 相似文献
12.
CdTe epitaxial layers are grown by metalorganic vapor phase epitaxy (MOVPE) on patterned (100) Si and (100) GaAs substrates
using SiO2, Si3N4 or CaF2 masks. Selective epitaxy of CdTe can be achieved by using Si3N4 and CaF2 masks and by controlling the growth conditions during MOVPE. The selectively grown CdTe layers show strong anisotropy depending
on the orientation of the window pattern on the mask, as well as on the orientation of the starting substrates. CdTe with
smooth atomically flat surfaces and vertical side walls can be obtained on (100) GaAs substrates by suitably orienting the
window pattern directions and optimizing the growth conditions. For the growth conditions that are suitable for the selective
growth, the growth is mass-transfer limited. The lateral growth rate depends on the ratio of the window width to the mask
width. Use of CaF2 allows wider temperature window for selective growth since no nucleation was observed on CaF2 even at 450°C. 相似文献
13.
Kevin Skenes Arkadeep Kumar R. G. R. Prasath Steven Danyluk 《Journal of Electronic Materials》2018,47(2):1030-1037
Near-infrared (NIR) polariscopy is a technique used for the non-destructive evaluation of the in-plane stresses in photovoltaic silicon wafers. Accurate evaluation of these stresses requires correct identification of the stress-optic coefficient, a material property which relates photoelastic parameters to physical stresses. The material stress-optic coefficient of silicon varies with crystallographic orientation. This variation poses a unique problem when measuring stresses in multicrystalline silicon (mc-Si) wafers. This paper concludes that the crystallographic orientation of silicon can be estimated by measuring the transmission of NIR light through the material. The transmission of NIR light through monocrystalline wafers of known orientation were compared with the transmission of NIR light through various grains in mc-Si wafers. X-ray diffraction was then used to verify the relationship by obtaining the crystallographic orientations of these assorted mc-Si grains. Variation of transmission intensity for different crystallographic orientations is further explained by using planar atomic density. The relationship between transmission intensity and planar atomic density appears to be linear. 相似文献
14.
New and simple modification of vapor-liquid-solid process for Si nanowires growth based on microwave plasma enhanced chemical vapor deposition that uses solid-state Si target as a source of Si atoms was developed. The method was temperature and pressure controlled evaporation of solid phase of Si source in hydrogen microwave plasma. Aligned growth of Si nanowires was performed in local electric field by applying of constant negative bias to substrate holder. Deposited Si nanowires were studied by scanning electron microscopy (SEM), Raman and photoluminescence spectroscopy. Correlation between photoluminescence spectra and Si nanowires properties were studied. 相似文献
15.
R. Beccard A. Dehe K. Heime G. Laube P. Speier 《Journal of Electronic Materials》1991,20(12):1033-1036
We have investigated the selective growth of InP in a low pressure hydride VPE system. Although the system operates further from thermodynamical equilibrium than the atmospheric pressure VPE system, high selectivity is found in a wide temperature range. The effects of the deposition temperature, the orientation and the geometric dimensions of the selectively grown structures on the growth behaviour are investigated. Additional experiments using unpatterned substrates of different surface orientations are performed to explain the formation of the typical shape of the structures. The results indicate that reaction kinetics mainly control the selective growth at low and medium growth temperatures. Only at high temperatures can effects of mass transfer be found. As a consequence, a comparable weak dependence of the growth rate on the width of selectively grown structures is found. 相似文献
16.
采用条形Al掩模在Si(111)衬底上进行了GaN薄膜侧向外延的研究.结果显示,当掩模条垂直于Si衬底[11-2]方向,也即GaN[10-10]方向时,GaN无法通过侧向生长合并得到表面平整的薄膜;当掩模条平行于Si衬底[11-2]方向,也即GaN[10-10]方向时,GaN侧向外延速度较快,有利于合并得到平整的薄膜.同时,研究表明,升高温度和降低生长气压都有利于侧向生长.通过优化生长工艺,在条形Al掩模Si(111)衬底上得到了连续完整的GaN薄膜.原子力显微镜测试显示,窗口区域生长的GaN薄膜位错密度约为1×109/cm2,而侧向生长的GaN薄膜位错密度降低到了5×107/cm2以下. 相似文献
17.
Zhimin Shi Jian-Jun He Sailing He 《Lightwave Technology, Journal of》2003,21(10):2314-2321
An analytic method of spatial phase modulation based on Fourier analysis is introduced for the design of a planar waveguide demultiplexer with a flat-top spectral response. An analytic formula for an etched diffraction grating demultiplexer is derived using the scalar diffraction theory. The spatial phase modulation is realized by slightly adjusting each grating facet's position according to the analytic formula to obtain a spectral response with a flat top and sharp transitions as well as a good dispersion characteristic. The analytic formula is characterized by two parameters: a transverse shift distance and a profile exponent for the phase modulation. A linear relation between the passband width and the transverse shift distance is given, and an optimal figure of merit of the spectral response is obtained by choosing an appropriate profile exponent. A numerical example of a typical SiO/sub 2/ etched diffraction grating demultiplexer is used to demonstrate the advantages of this method. 相似文献
18.
The principal solution type of spatial frequency transfer function (SFTF) for a linear antenna system, e.g., line source or linear array, is constant (flat) over its entire spatial frequency (SF) passband and drops abruptly to zero at the edges of the band. Such a SFTF is obtainable with cross-correlation (multiplicative) techniques. The associated power pattern, of thesin (Lu)/Lu type, has high sidelobes diminishing asymptotically asu^{-1} . Moreover, the weighting distribution for the line source has an inverse taper with end point singularities. A modified principal solution SFTF, flat over most of the SF passband but with a smoothly varying transition function of the quadratic-linear-quadratic type at the edges of the passband is introduced. This engenders a power pattern whose sidelobes diminish asymptotically asu^{-3} instead ofu^{-1} . The line source weighting distributions, moreover, are continuous and free of singularities, making physical realizability no longer a problem. 相似文献
19.
Hillocks are formed sporadically in Al-l%Si sputter layers on SiO2/Si substrates during heat treatments in the range from 200 to 500°C. The driving force is the relaxation of thermomechanical
stress in the grains induced by the thermal expansion mismatch between the metallization layer and the substrate. The orientations
of individual grains and hillocks are measured on-line with a medium voltage transmission electron microscope by the Kikuchi
pattern method. Thermomechanical stress in the grains is calculated with a biaxial strain model, considering the glide systems
of dislocations for the individual grain orientations. In general, hillocks deviate from the ordinary 〈111〉 fiber texture
of aluminum sputter layers. The spatial distribution of grain orientations is illustrated by orientation images using Miller
indices or Rodrigues vectors. 相似文献
20.
D. Grützmacher J. Hergeth F. Reinhardt K. Wolter P. Balk 《Journal of Electronic Materials》1990,19(5):471-479
GalnAs/lnP multiple quantum wells of 10 periods grown by low pressure metal organic vapor phase epitaxy were studied using
a careful analysis of their photoluminescence (PL) spectra and of supporting x-ray data. The results demonstrate extremely
precise control of the well width. The width of well and barrier can be reproducibly adjusted by a fraction of a monolayer.
This allows one to distinguish between 3-dimensional (3-D) and 2-dimensional (2-D) growth, which determines the lateral extent
of the atomically smooth interfacial areas. By varying the growth time per well a discontinuous energy shift of the PL peaks
is obtained for wells with widths from 1 to 8 monolayers. We show that this discontinuous energy shift corresponds to a change
in well width by one monolayer. It is also observed when growth at the upper interface is carried on without interruption
and a thin quaternary film is deposited at the interface. From these results the presence of atomically flat surfaces during
the growth is deduced; these give a strong indication of a 2-D mode of growth for an optimized set of parameters. 相似文献