A surfactant-mediated relaxed Si0.5Ge0.5 graded layer with a very low threading dislocation density and smooth surface

1999 ◽  
Vol 75 (11) ◽  
pp. 1586-1588 ◽  
Author(s):  
J. L. Liu ◽  
C. D. Moore ◽  
G. D. U’Ren ◽  
Y. H. Luo ◽  
Y. Lu ◽  
...  
Keyword(s):  
Dislocation Density ◽  
Smooth Surface ◽  
Threading Dislocation ◽  
Threading Dislocation Density

Growth of high quality Ge epitaxial layer on Si(100) substrate using ultra thin Si0.5Ge0.5 buffer

2005 ◽  
Vol 891 ◽  
Author(s):  
Junko Nakatsuru ◽  
Hiroki Date ◽  
Supika Mashiro ◽  
Manabu Ikemoto
Keyword(s):  
High Temperature ◽  
Dislocation Density ◽  
Buffer Layer ◽  
Epitaxial Layer ◽  
Seed Layer ◽  
Smooth Surface ◽  
Layer Growth ◽  
Process Time ◽  
Threading Dislocation ◽  
Threading Dislocation Density

ABSTRACTMethods for forming Ge epitaxial layer on Si (100) substrate have been vigorously sought due to potential applications of such structure as a virtual substrate for III-V devices on Si. Various methods were proposed to realize low threading dislocation density and smooth surface. To date, such methods involve more than one of thick (micrometer order) SiGe buffer growth process, high temperature annealing steps and CMP process, which could compromise reliability and suitability for production.In this study, we report feasibility of a thin (in the order of 10nm) SiGe buffer layer to realize pure Ge epitaxial layer with good crystalinity, low threading dislocation density, and smooth surface without high temperature annealing steps and CMP process.As a result, we achieved shorter time for growth of practical thickness of crystalline Ge on Si (100) substrate, and also get the high quality Ge epitaxial layer which has low threading dislocation density with very smooth surface.Ge epitaxial layer and underlying thin SixGe1−x buffer layer were grown on Si (100) substrate using a cold wall UHV-CVD system. Source gases of Si and Ge were Si2H6 and GeH4, respectively. No carrier gas was used for this process. SiGe buffer layer was grown on Si(100) substrate at 450 – 520˚C. Two-step growth process was employed to grow Ge epitaxial layer on the buffer layer. Ge seed layer was grown at a low temperature (350–400˚C), followed by Ge thick layer growth at a high temperature (550–650˚C). XRD, TEM, EPD, and AFM were used for characterization of Ge epitaxial layer.Optimization of growth temperature and source gas flow rate ratio enabled to obtain an effective buffer layer thinner than 10nm. The thin buffer layer realizes process time shortening, which is within 10min, and the smooth surface is realized without crosshatch structure. The buffer thickness is 1/160 to 1/1000 than that of previously known methods using thick SiGe buffer layers. Thin SiGe buffer also enabled process time shortening for Ge seed layer growth as two-dimensional Ge layer was formed faster on the thin SiGe buffer layer than on Si. XRD of the Ge seed layer showed 97% relaxation as grown and fully relaxed at 550˚C. The threading dislocation density of the top Ge layer was estimated below 1E7counts/cm2 by TEM and EPD.The misfit dislocations oriented along [110] at the interface between the SiGe buffer layer and the Ge layer and the distances are 9.5nm constantly in cross-sectional TEM image. We are checking the surface roughness of the Ge epitaxial layer by using AFM.

High-Irradiance Degradation Studies of Metamorphic 1eV GaInAs Solar Cells

2012 ◽  
Vol 1432 ◽  
Author(s):  
Ryan M. France ◽  
Myles A. Steiner
Keyword(s):  
Solar Cells ◽  
Active Region ◽  
Dislocation Density ◽  
Dark Current ◽  
Degradation Mechanism ◽  
Control Cell ◽  
High Irradiance ◽  
Threading Dislocation ◽  
Threading Dislocation Density ◽  
Degradation Studies

ABSTRACTInitial tests are performed regarding the degradation of lattice-mismatched GaInAs solar cells. 1eV metamorphic GaInAs solar cells with 1-2×106 cm-2 threading dislocation density in the active region are irradiated with an 808 nm laser for 2 weeks time under a variety of temperature and illumination conditions. All devices show a small degradation in Voc that is logarithmic with time. The absolute loss in performance after 2 weeks illuminated at 1300 suns equivalent and 125°C is 7 mV Voc and 0.2% efficiency, showing these devices to be relatively stable. The dark current increases with time and is analyzed with a two-diode model. A GaAs control cell degrades at the same rate, suggesting that the observed degradation mechanism is not related to the additional dislocations in the GaInAs devices.

Relationship between misfit-dislocation formation and initial threading-dislocation density in GaInN/GaN heterostructures

2015 ◽  
Vol 54 (11) ◽  
pp. 115501 ◽  
Author(s):  
Motoaki Iwaya ◽  
Taiji Yamamoto ◽  
Daisuke Iida ◽  
Yasunari Kondo ◽  
Mihoko Sowa ◽  
...  
Keyword(s):  
Dislocation Density ◽  
Misfit Dislocation ◽  
Threading Dislocation ◽  
Threading Dislocation Density ◽  
Dislocation Formation

Enhanced reduction in threading dislocation density in Ge grown on porous silicon during annealing due to porous buffer reconstruction

2015 ◽  
Vol 213 (1) ◽  
pp. 96-101
Author(s):  
G. Calabrese ◽  
S. Baricordi ◽  
P. Bernardoni ◽  
D. De Salvador ◽  
M. Ferroni ◽  
...  
Keyword(s):  
Porous Silicon ◽  
Dislocation Density ◽  
Threading Dislocation ◽  
Threading Dislocation Density

Defect-Engineered Graded GexSi1-x Buffers on Si (001) with Extreme Low Threading Dislocation Density

1995 ◽  
Vol 378 ◽  
Author(s):  
G. Kissinger ◽  
T. Morgenstern ◽  
G. Morgenstern ◽  
H. B. Erzgräber ◽  
H. Richter
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Atomic Force Microscopy ◽  
Dislocation Density ◽  
Threading Dislocation ◽  
Force Microscopy ◽  
Atomic Force ◽  
Transmission Electron ◽  
Dislocation Densities ◽  
Threading Dislocation Density

AbstractStepwise equilibrated graded GexSii-x (x≤0.2) buffers with threading dislocation densities between 102 and 103 cm−2 on the whole area of 4 inch silicon wafers were grown and studied by transmission electron microscopy, defect etching, atomic force microscopy and photoluminescence spectroscopy.

Evaluation of threading dislocation density of strained Ge epitaxial layer by high resolution x-ray diffraction

2017 ◽  
Vol 26 (12) ◽  
pp. 127309 ◽  
Author(s):  
Yuan-Hao Miao ◽  
Hui-Yong Hu ◽  
Xin Li ◽  
Jian-Jun Song ◽  
Rong-Xi Xuan ◽  
...  
Keyword(s):  
High Resolution ◽  
Dislocation Density ◽  
Epitaxial Layer ◽  
Threading Dislocation ◽  
X Ray Diffraction ◽  
X Ray ◽  
Threading Dislocation Density
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