Undoped GaAs with a Low Electron Concentration Grown on Si by Mocvd

1990 ◽  
Vol 198 ◽  
Author(s):  
Shinji Nozaki ◽  
A. T. Wu ◽  
J. J. Murray ◽  
T. George ◽  
M. Umeno
Keyword(s):  
Electron Concentration ◽  
Gaas Layer ◽  
High Resistivity ◽  
Si Substrate ◽  
Mocvd Reactor ◽  
Mocvd Growth ◽  
Step Growth ◽  
Gas Phase Transport ◽  
Phase Transport ◽  
Undoped Gaas

ABSTRACTWe have successfully grown undoped GaAs of very high resistivity on Si by MOCVD. The back and side edges of the Si substrate were coated with a Si3N4/SiO2 stacked layer to suppress Si incorporation Into GaAs by the gas phase transport mechanism during MOCVD growth. A 3- μm-thick GaAs layer was grown on this Si substrate at 750 °C in an atmospheric MOCVD reactor using the two-step growth technique. The electron concentration measured by a Polaron C-V profiler is 3xl0l4 cm−3, as low as that of GaAs grown on GaAs substrate, up to the depth of 1.5 μm from the surface.

Characteristics of Mocvd-Grown AlGaAs/GaAs Sqw Lasers and GaAs Mesfetsfabrication on Si Substrate with SiO2-Back Coating

1990 ◽  
Vol 198 ◽  
Author(s):  
Takashi Egawa ◽  
Hitoshi Tada ◽  
Yasufumi Kobayashi ◽  
Shinji Nozaki ◽  
Tetsuo Soga ◽  
...  
Keyword(s):  
Electron Concentration ◽  
Thermal Cycle ◽  
Room Temperature ◽  
Threshold Current ◽  
Gaas Layer ◽  
Si Substrate ◽  
Thermal Cycle Annealing ◽  
Cw Operation ◽  
Lower Background ◽  
Undoped Gaas

ABSTRACTWe discuss room temperature CW operation of AlGaAs/GaAs SQW lasers and GaAs MESFETs with good pinch-off characteristic on SiO2 -back coated Si. The all-MOCVD-grown,SQW laser on Si with thermal-cycle annealing, which has the EPD of 1.5 × 107 cm−2, has the threshold current as low as 55 mA (1.41 kA/cm2) under CW operation at room temperature. The pinch-off and the sidegating effect characteristics of GaAs MESFETs on Si have been improved by using SiO2-back coating of Si and higher growth temperature. The maximum transconductance of 160 mS/mm has been obtained for the MESFET with a 2.5 × 15 µm gate. The main origin of sidegating effect associates with the channel layer-undoped GaAs layer beneath it interface. The SiO2 -back coating is found effective to obtain a lower background electron concentration in undoped GaAs layer and to control doping of the active layer in GaAs/Si.

Mocvd Growth of GaAs on Si

1988 ◽  
Vol 116 ◽  
Author(s):  
Masahiro Akiyama ◽  
Takash Ueda ◽  
Sachiko Onozawa
Keyword(s):  
High Temperatures ◽  
Growth Temperature ◽  
Room Temperature ◽  
Gaas Layer ◽  
Grown Layer ◽  
Gaas On Si ◽  
Mocvd Growth ◽  
Initial Stage ◽  
Step Growth ◽  
Domain Property

AbstractThe initial stage of the growth of GaAs on Si by, MOCVD, the reduction of the residual dislocations by annealing at high temperatures and the dependence of the growth temperature on the stress in the GaAs layer were studied. The density and the size of deposited GaAs islands at the initial stage of the growth in the two-step growth sequence strongly affected the domain property of the subsequently grown layer. For reducing the residual dislocations by annealing at high temperatures, to repeat the growth and the annealing was more effective method compared with the other annealing methods we tried. The stress in the GaAs layers showed a constant value independently of the growth temperature and the value was related to the thermal expansion between room temperature and about 350°C.

scholarly journals NMR imaging of low pressure, gas-phase transport in packed beds using hyperpolarized xenon-129

AIChE Journal ◽  
2015 ◽  
Vol 61 (11) ◽  
pp. 4013-4019 ◽  
Author(s):  
Galina Pavlovskaya ◽  
Joseph Six ◽  
Thomas Meersman ◽  
Navin Gopinathan ◽  
Sean P. Rigby
Keyword(s):  
Gas Phase ◽  
Low Pressure ◽  
Nmr Imaging ◽  
Packed Beds ◽  
Hyperpolarized Xenon ◽  
Gas Phase Transport ◽  
Phase Transport

Gradients and Assumptions Affect Interpretation of Laboratory-Measured Gas-Phase Transport

2015 ◽  
Vol 79 (4) ◽  
pp. 1018-1029 ◽  
Author(s):  
Robert P. Ewing ◽  
Behzad Ghanbarian ◽  
Allen G. Hunt
Keyword(s):  
Gas Phase ◽  
Gas Phase Transport ◽  
Phase Transport

scholarly journals Gas Transfer of Metals during the Destruction of Efflorescent Sulfates from the Belovo Plant Sulfide Slag, Russia

Minerals ◽  
2019 ◽  
Vol 9 (6) ◽  
pp. 344
Author(s):  
Svetlana Bortnikova ◽  
Natalya Abrosimova ◽  
Nataliya Yurkevich ◽  
Valentina Zvereva ◽  
Anna Devyatova ◽  
...  
Keyword(s):  
Major And Trace Elements ◽  
Water Molecules ◽  
Gas Transfer ◽  
Structural Water ◽  
Fermentation Products ◽  
X Ray ◽  
Gas Condensates ◽  
Gas Phase Transport ◽  
Phase Transport

This paper demonstrates the results of experiments for the determination of the composition of gases during the dehydration of sulfates (Na-jarosite, melanterite, and chalcanthite) collected at the surface of pyrometallurgical waste heaps. The volatilization of various elements, and vapor–gas phase transport from three sulfate groups were investigated by stepwise laboratory heating at 45, 55, and 65 °C. The sample of yellow efflorescence mainly consisted of Na-jarosite, the white efflorescence contained melanterite as the major mineral, and the blue efflorescence sample consisted of chalcanthite. These all contained a few impurities up to 5 %. The highest total dissolved solids (TDS) was found in the gas condensates from melanterite (59 mg/L), followed by chalcanthite (29 mg/L) and Na-jarosite (17 mg/L). It was determined that major and trace elements in the condensate can be trapped by water vapor and can migrate with the vapor phase during the desorption and dehydration of hydrous sulfates. X-ray diffractograms showed that Na-jarosite remained stable throughout the temperature range, whilst the separation of melanterite’s structural water occurred at 40 °C, and chalcanthite completely lost two water molecules at 50 °C. The gas condensates contained acetates and formates, which could be the fermentation products of bacterial communities. Some of the strains—Micrococcaceae sp., Bacillus sp., and Microbacteriaceae sp.—were cultivated.

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