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1.
利用课题组自主研发的热壁低压化学气相沉积(HWLPCVD)系统,在朝[11-20]方向偏转4°的(0001)Si面4H-SiC衬底上进行快速同质外延生长,研究了生长温度及氯硅比(Cl/Si比)对外延生长速率的影响机理.研究发现,外延生长速率随生长温度的提高呈线性增加,而Cl/Si比的改变对生长速率的影响不大.文章进一步探究了Cl/Si比对4H-SiC外延层表面缺陷的影响.较低的Cl/Si比(0.4~2)可以减少或消除三角缺陷,Cl/Si比较高(大于5)时,表面质量反而下降,因而,适当的Cl/Si比对于获得表面形貌良好的4H-SiC外延层至关重要. 相似文献
2.
S. V. Rendakova I. P. Nikitina A. S. Tregubova V. A. Dmitriev 《Journal of Electronic Materials》1998,27(4):292-295
We investigated silicon carbide (SiC) epitaxial layers grown by liquid phase epitaxy (LPE). The layers were grown on 6H-SiC
and 4H-SiC well-oriented (0001) 35 mm diameter commercial wafers as well as on 6H-SiC Lely crystals. A few experiments were
also done on off-axis 6H-SiC and 4H-SiC substrates. Layer thickness and growth rate ranged from 0.5 to 50 microns and 0.5
to 10 μm/h, respectively. Layers were investigated by x-ray diffraction, x-ray topography, and selective chemical etching
in molten KOH. It was found that dislocation and micropipe density in LPE grown epitaxial layers were significantly reduced
compared with the defect densities in the substrates. 相似文献
3.
Katsunori Danno Tsunenobu Kimoto Katsunori Asano Yoshitaka Sugawara Hiroyuki Matsunami 《Journal of Electronic Materials》2005,34(4):324-329
4H-SiC(
) epitaxial layers with a 14–28-μm thickness have been grown at high growth rates of 14–19 μm/h by chimney-type, vertical
hot-wall, chemical vapor deposition (CVD) at 1,750°C. The 3C hillocks are formed on the epilayers grown under relatively low
C/Si ratios. When grown at a relatively higher C/Si ratio of 0.6, the hillock density has been decreased to 1 cm−2. Under the C-rich condition, the concentrations of residual impurity (nitrogen) and intrinsic defects (Z1/2 and EH6/7) have been reduced. When growth has been performed at low C/Si ratios of 0.4 and 0.5, all the micropipes in the substrates
(more than 100 micropipes for each condition) have been closed during CVD growth. 相似文献
4.
为了获得高质量4H-SiC外延材料,研制出一套水平式低压热壁CVD(LP-HWCVD)生长系统,在偏晶向的4H-SiC Si(0001)晶面衬底上,利用"台阶控制生长"技术进行了4H-SiC的同质外延生长,典型生长温度和压力分别为1500℃和1.3×103Pa,生长速率控制在1.0μm/h左右.采用Nomarski光学显微镜、扫描电镜(SEM)、原子力显微镜(AFM)、X射线衍射、Raman散射以及低温光致发光测试技术,研究了4H-SiC的表面形貌、结构和光学特性以及用NH3作为n型掺杂剂的4H-SiC原位掺杂技术,并在此基础上获得了4H-SiC p-n结二极管以及它们在室温及400℃下的电致发光特性,实验结果表明4H-SiC在Si不能工作的高温环境下具有极大的应用潜力. 相似文献
5.
使用三氯硅烷(TCS)作为含氯生长源,在多片外延设备生长了高质量的4H-SiC外延材料.研究了原位预刻蚀气体HCl流量和刻蚀时间对SiC外延材料表面三角形缺陷的影响,使用光学显微镜和表面缺陷分析仪对SiC外延材料表面缺陷进行表征测试和统计,使用傅里叶红外测试仪(FTIR)和原子力显微镜(AFM)对外延材料表面形貌进行表征.结果表明,预刻蚀气体体积流量和时间对4英寸SiC外延材料表面三角形缺陷影响明显,随着HCl体积流量和时间的增加,材料表面的三角形缺陷密度先减小后增加,在HCl流量为100 mL/min、刻蚀时间为20 min时,三角形缺陷密度最低达到0.47cm-2.此外,通过调整C/Si比和载气体积流量等参数,使4英寸SiC外延材料掺杂浓度不均匀性和厚度不均匀性均得到有效改善,结果表明该外延片质量满足SiC电力电子器件的应用. 相似文献
6.
R. D. Dupuis J. C. Bean J. M. Brown A. T. Macrander R. C. Miller L. C. Hopkins 《Journal of Electronic Materials》1987,16(1):69-77
We report the results of studies which have been made on heteroepitaxial layers of GaAs and AlGaAs grown by metalorganic chemical
vapor deposition on composite substrates that consist of four different types of heteroepitaxial layered structures of Ge
and Ge-Si grown by molecular beam epitaxy on (100)-oriented Si substrates. It is found that of the four structures studied,
the preferred composite substrate is a single layer of Ge ∼1 μm thick grown directly on a Si buffer layer. The double-crystal
X-ray rocking curves of 2 μm thick GaAs films grown on such substrates have FWHM values as small as 168 arc sec. Transmission
electron micrographs of these Ge/Si composite substrates has shown that the number of dislocations in the Ge heteroepitaxial
layer can be greatly reduced by an anneal at about 750° C for 30 min which is simultaneously carried out during the growth
of the GaAs layer. The quality of the GaAs layers grown on these composite substrates can be greatly improved by the use of
a five-period GaAs-GaAsP strained-layer superlattice (SLS). Using the results of these studies, low-threshold optically pumped
AlGaAs-GaAs DH laser structures have been grown by MOCVD on MBE Ge/Si composite substrates. 相似文献
7.
Z. C. Feng A. Rohatgi C. C. Tin R. Hu A. T. S. Wee K. P. Se 《Journal of Electronic Materials》1996,25(5):917-923
A series of epitaxial 4H-SiC thin films grown by low pressure chemical vapor deposition (LPCVD) were characterized using various
techniques, including x-ray diffraction (XRD), Fourier transform infrared (FTIR) reflectance, Raman scattering, and x-ray
photoelectron spectroscopy (XPS). The epilayers were grown on heavily doped n-type 4H-SiC substrates using different gas compositions.
XRD showed that the thin films were single crystal. Raman scattering identified the films to be 4H polytype. FTIR reflectivity
spectra indicated improvement in the film quality over that of the substrate and atmospheric pressure-grown epilayers. XPS
scans revealed the existence of Si, C, and O along with C-contaminant species in the form of CH and carbon oxides. Variations
in crystalline quality, optical, and surface properties with the growth conditions were studied. This study also provides
an important comparison between low and atmospheric pressure-grown 4H-SiC epilayers. 相似文献
8.
在高纯半绝缘4H-SiC偏8°衬底上同质外延生长了高质量的外延层,利用X射线双晶衍射、原子力显微镜(AFM)、汞探针C-V以及霍尔效应等测试方法,对样品的结晶质量、表面粗糙度、掺杂浓度以及电子迁移率进行了分析测试,证实外延层的结晶质量相对于衬底有着很大的改善。在同质外延7.5μm的外延层后,其半高宽从衬底的30.55arcsec减小到27.85arcsec;外延层表面10μm×10μm的粗糙度(RMS)为0.271nm;室温下,样品的掺杂浓度为1×1015cm-3时,霍尔迁移率高达987cm2/(V.s);浓度为1.5×1016cm-3时,霍尔迁移率为821cm2/(V.s)。77K时,霍耳迁移率分别为1.82×104cm2/(V.s)和1.29×104cm2/(V.s)。掺杂浓度的汞探针C-V测试结果与霍尔效应的实验数据一致。 相似文献
9.
Monocrystalline 6H-SiC thin films have been epitaxially grown on off-axis 6H-SiC {0001} substrates in the temperature range
of 1623–1873 K via chemical vapor deposition. The growth rate was a strong function of the growth temperature and the reactant
gas concentration. The activation energies for growth were 64 kJ/mole and 55 kJ/mole for the (0001) Si face and the (0001)
C face, respectively. The concentration of growth pits in the films increased as a function of decreasing deposition temperature,
increasing concentration of reactant gases and increasing off-axis orientation. Beta-SiC islands were also observed in the
epilayers when the (SiH4 + C2H4)/H2 ratio was ≥2.5:3000. 相似文献
10.
In this research effort, we investigate the influence of the cold-wall reactor geometry on the chemical vapor deposition (CVD)
growth process of 4H-SiC and the quality of lightly doped epitaxial layers. Stable growth conditions with respect to growth
rate and C/Si ratio of the gas-phase can be achieved by the appropriate choice of the distance between susceptor and walls
of the inner quartz tube. A background doping concentration in the range of 1014 cm−3 is realized by employing a high temperature stable and hydrogen etch resistant coating of the graphite susceptor. Doping
and thickness homogeneity of epitaxial layers on 35 mm diam. 4H-SiC substrates, expressed by σ/mean, are as low as 6.9 and
7.7%, respectively. From deep level transient spectroscopy measurements, the concentration of the frequently reported intrinsic
Z1-center in 4H-SiC is determined to be below the detection limit of 1012 cm−3. 相似文献
11.
A. E. Nikolaev S. V. Rendakova I. P. Nikitina K. V. Vassilevski V. A. Dmitriev 《Journal of Electronic Materials》1998,27(4):288-291
6H-SiC/GaN pn-heterostructures were grown by subsequent epitaxial growth of p-SiC by low temperature liquid phase epitaxy
(LTLPE) and n-GaN by hydride vapor phase epitaxy (HVPE). For the first time, p-type epitaxial layers grown on 6H-SiC wafers
were used as substrates for GaN HVPE growth. The GaN layers exhibit high crystal quality which was determined by x-ray diffraction.
The full width at a half maximum (FWHM) for the ω-scan rocking curve for (0002) GaN reflection was ∼120 arcsec. The photoluminescence
spectra for these films were dominated by band-edge emission. The FWHM of the edge PL peak at 361 nm was about 5 nm (80K). 相似文献
12.
A growth parameter study was made to determine the proper of a SiGe superlattice-type configuration grown on Si substrates
by chemical vapor deposition (CVD). The study included such variables as growth temperature, layer composition, layer thickness,
total film thickness, doping concentrations, and film orientation. Si and SiGe layers were grown using SiH4 as the Si source and GeH4 as the Ge source. When intentional doping was desired, diluted diborane for p-type films and phosphine for n-type films were
used. The study led to films grown at ∼1000°C with mobilities from ∼20 to 40 percent higher than that of epitaxial Si layers
and ∼100 percent higher than that of epitaxial SiGe layers grown on (100) Si in the same deposition system for net carrier
concentrations of ∼8x1015 cm-3 to ∼2x1017 cm-3. Enhanced mobilities were found in multilayer (100)-oriented Si/Si1-xGex films for layer thicknesses ≥400A, for film thicknesses >2μm, and for layers with x = 0.15. No enhanced mobility was found
for (111)-oriented films and for B-doped multilayered (100)-orlented films.
Supported in part by NASA-Langley Research Center, Hampton, VA, Contract NAS1-16102 (R. Stermer & A. Fripp, Contr. Mon.) 相似文献
13.
Tianbing Chen Zhiyun Luo John D. Cressler Tamara F. Isaacs-Smith John R. Williams Gilyong Chung Steve D. Clark 《Solid-state electronics》2002,46(12):2231-2235
The radiation response of SiO2 gate oxides grown on 4H-SiC to NO passivation is presented for the first time. The effects of gamma radiation on Qeff are similar for n-4H-SiC MOS capacitors both with and without NO passivation, but are different in sign (negative) compared to SiO2 on Si. The variation in Dit with total dose, however, is different for the passivated versus the unpassivated samples. Comparisons between Si SOI and 4H-SiC suggest that properly passivated SiC MOSFETs should have good radiation tolerance. 相似文献
14.
利用新研制出的垂直式低压CVD(LPCVD)SiC生长系统,获得了高质量的50mm 3C-SiC/Si(111)衬底材料.系统研究了3C-SiC的n型和p型原位掺杂技术,获得了生长速率和表面形貌对反应气体中SiH4流量和C/Si原子比率的依赖关系.利用Hall测试技术、非接触式方块电阻测试方法和SIMS,分别研究了3C-SiC的电学特性、均匀性和故意调制掺杂的N浓度纵向分布.利用MBE方法,在原生长的50mm 3C-SiC/Si(111)衬底上进行了GaN的外延生长,并研究了GaN材料的表面、结构和光学特性.结果表明3C-SiC是一种适合于高质量无裂纹GaN外延生长的衬底或缓冲材料. 相似文献
15.
Epitaxial (100) CdTe and ZnTe layers with high crystalline quality have been grown on Si substrates by atmospheric pressure
organometallic vapor phase epitaxy (OMVPE). A thin Ge interfacial layer grown at low temperature was used as a buffer layer
prior to ZnTe and CdTe growth. The layers were characterized by Nomarski optical microscopy and double crystal x-ray diffraction.
Double crystal rocking curves with full width at half maximum of about 110 and 250 arc-sec have been obtained for a 7 μm thick
ZnTe layer and a 4 μm thick CdTe layer, respectively. The results presented demonstrate a novel method ofin-situ Si cleaning step without a high temperature deoxidation process to grow high quality CdTe and ZnTe on Si in a single OMVPE
reactor. 相似文献
16.
K. Yasuda H. Hatano T. Ferid K. Kawamoto T. Maejima M. Minamide 《Journal of Electronic Materials》1995,24(9):1093-1097
Growth characteristics of (100) HgCdTe (MCT) layers by MOVPE at low temperature of 275°C were studied using ditertiarybutyltelluride
as a tellurium precursor. Growths were conducted in a vertical narrow-spacing growth cell at atmospheric pressure. Cd composition
of MCT layers were controlled from 0 to 0.98 using dimethylcadmium (DMCd) flow. The growth rate was constant for increase
of DMCd flow. During the growth, Cd was incorporated preferentially into the MCT layers. Enhancement of Cd incorporation in
the presence of Hg was also observed. Crystal quality and electrical properties were also evaluated, which showed that high
quality MCT layers can be grown at 275°C. Strain in CdTe layers grown at 425 and 275°C was also evaluated. Lattice parameter
of layers grown at 425°C approached bulk value at thickness of 5 μm, while layers grown at 275°C relaxed at 1 μm. The rapid
strain relaxation of layers grown at 275°C was considered due to the layer growth on the strain relaxed buffer layer. The
effect of the thermal stress on the relaxation of CdTe lattice strain was also discussed. 相似文献
17.
LI Dai-zong YU Zhuo CHEN Bu-wen HUANG Chang-jun LEI Zhen-lin YU Jin-zhong WANG Qi-ming 《半导体光子学与技术》1999,5(3):134-138
Using double crystal X-rays diffraction (DCXRD) and atomic force microscopy (AFM), the results of Ge x Si 1- x grown by UHV/CVD from Si 2H 6 and SiH 4 are analyzed and compared. Adsorbates can migrate to the energy-favoring position due to the slow growth rate from SiH 4. In this case, a Si buffer that isolates the effect of substrate on epilayer could not be grown, which results in a pit penetrating into epilayer and buffer. The FWHM is 0.055° in DCXRD from SiH 4. The presence of diffraction fringes is an indication of an excellent crystalline quality. The roughness of the surface is improved if grown by Si 2H 6; however, the crystal quality of the Ge x Si 1- x material became worse than that from SiH 4 due to much larger growth rate from Si 2H 6. The content of Ge is obtained from DCXRD, which indicates the growth rate from Si 2H 6 is largest, then GeH 4, and that from SiH 4 is least. 相似文献
18.
G. Kipshidze S. Nikishin V. Kuryatkov K. Choi Ìu. Gherasoiu T. Prokofyeva M. Holtz H. Temkin K. D. Hobart F. J. Kub M. Fatemi 《Journal of Electronic Materials》2001,30(7):825-828
Epitaxial layers of AlN and GaN were grown by gas source molecular-beam epitaxy on a composite substrate consisting of a thin
(250 nm) layer of silicon (111) bonded to a polycrystalline SiC substrate. Two dimensional growth modes of AlN and GaN were
observed. We show that the plastic deformation of the thin Si layer results in initial relaxation of the AlN buffer layer
and thus eliminates cracking of the epitaxial layer of GaN. Raman, x-ray diffraction, and cathodoluminescence measurements
confirm the wurtzite structure of the GaN epilayer and the c-axis crystal growth orientation. The average stress in the GaN
layer is estimated at 320 MPa. This is a factor of two less than the stress reported for HVPE growth on 6H-SiC (0001). 相似文献
19.
A. Prez-Toms M.R. Jennings M. Davis V. Shah T. Grasby J.A. Covington P.A. Mawby 《Microelectronics Journal》2007,38(12):1233-1237
The physical and electrical properties of heavily doped silicon (5×1019 cm−3) deposited by molecular beam epitaxy (MBE) on 4H-SiC are investigated in this paper. Silicon layers on silicon carbide have a broad number of potential applications including device fabrication or passivation when oxidised. In particular, Si/SiC contacts present several atractive material advantages for the semiconductor industry and especially for SiC processing procedures for avoiding stages such as high temperature contact annealing or SiC etching. Si films of 100 nm thickness have been grown using a MBE system after different cleaning procedures on n-type (0 0 0 1) Si face 8° off 4H-SiC substrates. Isotype (n–n) and an-isotype (p–n) devices were fabricated at both 500 and 900 °C using antimonium (Sb) or boron (B), respectively. X-ray diffraction analysis (XRD) and scanning electronic mircorscope (SEM) have been used to investigate the crystal composition and morphology of the deposited layers. The electrical mesurements were performed to determine the rectifiying contact characteristics and band offsets. 相似文献