1991 Fiscal Year Final Research Report Summary
Molecular Beam Epitaxial Growth of GaAs on Porous Si
| Project/Area Number |
01460077
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| Research Category |
Grant-in-Aid for General Scientific Research (B)
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| Allocation Type | Single-year Grants |
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| Research Field |
Applied materials
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| Research Institution | Osaka University |
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Principal Investigator |
NAKASHIMA Hisao Osaka Univ., ISIR. Professor, 産業科学研究所, 教授 (20198071)
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| Co-Investigator(Kenkyū-buntansha) |
KAWARADA Hiroshi Waseda Univ., Electronic and Communication Engineering, Associate Professor, 理工学部, 助教授 (90161380)
ITO Toshimiti Osaka Univ., Electrical Engineering, Associate Professor, 工学部, 助教授 (00183004)
MAEHASHI Kenzo Osaka Univ., Technical Staff, 産業科学研究所, 教務職員 (40229323)
HASEGAWA Shigehiko Osaka Univ., ISIR, Research Assistant, 産業科学研究所, 助手 (50189528)
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| Project Period (FY) |
1989 – 1991
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| Keywords | Porous Si / GaAs / Molecular Beam Epitaxy / Photoelectron Spectroscopy / High energy Ion Scattering / Reflection High Energy Electron Diffraction / Initial Growth Stage / Defects |
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| Research Abstract |
Growth of GaAs on Si substrates has attracted considerable interest as a promising way to combine silicon integrated circuits with electronic and optical GaAs devices. Because of high density of dislocation due to lattice mismatch and large difference in the thermal expansion coefficients, GaAs layers with good crystallnity have not been obtained. To reduce the dislocation density, GaAs layers are grown on porous Si substrates by MBE. Flexibility of porous Si is expected to relax the stresses due to the large misfit and large difference in thermal expansion coefficients. It is found that many defects still exist at the GaAs/porous Si interfaces as well as in the GaAs by Rutherford backscattering spectrometry. Studies of the initial stages of GaAs layers on porous Si reveal that the change in morphology of the porous Si causes the rough interfaces and defective GaAs layers. The change in surface morphology of the porous Si is avoided by slightly oxidizing porous Si. Thin Si layers are grown on this oxidizing porous substrates and then GaAs layers are grown on the Si layers. Curvature of this sample is greatly reduces compared with that of the conventional GaAs on Si sample. However, there still exist a large number of dislocations in GaAs layers, which are found to be induced by imperfect cleaning of oxidized porous Si substrates. Then, we adopt the new growth processes which include the growth of thin n-Si layers on p^+ substrates, the selective formation of porous layers, the oxidation of porous layers and the growth of GaAs layers. We are now studying the defects in these GaAs layers by changing the growth conditions.
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