We study the effect of the AlGaN interlayer on structural quality and strain engineering of the GaN films grown on SiC substrates with an AlN buffer layer, hnproved structural quality and tensile stress releasing are ...We study the effect of the AlGaN interlayer on structural quality and strain engineering of the GaN films grown on SiC substrates with an AlN buffer layer, hnproved structural quality and tensile stress releasing are realized in unintentionally doped GaN thin films grown on 6H-SiC substrates by metal organic chemical vapor deposition. Using the optimized AlGaN interlayer, we find that the full width at half maximum of x-ray diffraction peaks for GaN decreases dramatically, indicating an improved crystalline quality. Meanwhile, it is revealed that the biaxial tensile stress in the GaN film is significantly reduced from the Raman results. Photoluminescence spectra exhibit a shift of the peak position of the near-band-edge emission, as well as the integrated intensity ratio variation of the near-band-edge emission to the yellow luminescence band. Thus by optimizing the AlGaN interlayer, we could acquire the high-quality and strain-relaxation GaN epilayer with large thickness on SiC substrates.展开更多
Epitaxial Ge1-xSnx alloys are grown separately on a Ge-buffer/Si（100） substrate and directly on a Si（100） substrate by molecular beam epitaxy （MBE） at low temperature. In the case of the Ge buffer/Si（100） subs...Epitaxial Ge1-xSnx alloys are grown separately on a Ge-buffer/Si（100） substrate and directly on a Si（100） substrate by molecular beam epitaxy （MBE） at low temperature. In the case of the Ge buffer/Si（100） substrate, a high crystalline quality strained Ge0.97Sn0.03 alloy is grown, with a Xmin value of 6.7% measured by channeling and random Rutherford baekscattering spectrometry （RBS）, and a surface root-mean-square （RMS） roughness of 1.568 nm obtained by atomic force microscopy （AFM）. In the case of the Si（100） substrate, strain-relaxed Ge0.97Sn0.03 alloys are epitaxially grown at 150℃-300℃, with the degree of strain relaxation being more than 96%. The X-ray diffraction （XRD） and AFM measurements demonstrate that the alloys each have a good crystalline quality and a relatively flat surface. The predominant defects accommodating the large misfit are Lomer edge dislocations at the interface, which are parallel to the interface plane and should not degrade electrical properties and device performance.展开更多
基金Supported by the National Key R&D Program of China under Grant No 2016YFB0400200
文摘We study the effect of the AlGaN interlayer on structural quality and strain engineering of the GaN films grown on SiC substrates with an AlN buffer layer, hnproved structural quality and tensile stress releasing are realized in unintentionally doped GaN thin films grown on 6H-SiC substrates by metal organic chemical vapor deposition. Using the optimized AlGaN interlayer, we find that the full width at half maximum of x-ray diffraction peaks for GaN decreases dramatically, indicating an improved crystalline quality. Meanwhile, it is revealed that the biaxial tensile stress in the GaN film is significantly reduced from the Raman results. Photoluminescence spectra exhibit a shift of the peak position of the near-band-edge emission, as well as the integrated intensity ratio variation of the near-band-edge emission to the yellow luminescence band. Thus by optimizing the AlGaN interlayer, we could acquire the high-quality and strain-relaxation GaN epilayer with large thickness on SiC substrates.
基金Project supported by the National High Technology Research and Development Program of China (Grant No. 2006AA03Z415)the National Basic Research Program of China (Grant No. 2007CB613404)+1 种基金the National Natural Science Foundation of China (Grant Nos. 60906035 and 61036003)the Knowledge Innovation Program of the Chinese Academy of Sciences (Grant No. ISCAS2009T01)
文摘Epitaxial Ge1-xSnx alloys are grown separately on a Ge-buffer/Si（100） substrate and directly on a Si（100） substrate by molecular beam epitaxy （MBE） at low temperature. In the case of the Ge buffer/Si（100） substrate, a high crystalline quality strained Ge0.97Sn0.03 alloy is grown, with a Xmin value of 6.7% measured by channeling and random Rutherford baekscattering spectrometry （RBS）, and a surface root-mean-square （RMS） roughness of 1.568 nm obtained by atomic force microscopy （AFM）. In the case of the Si（100） substrate, strain-relaxed Ge0.97Sn0.03 alloys are epitaxially grown at 150℃-300℃, with the degree of strain relaxation being more than 96%. The X-ray diffraction （XRD） and AFM measurements demonstrate that the alloys each have a good crystalline quality and a relatively flat surface. The predominant defects accommodating the large misfit are Lomer edge dislocations at the interface, which are parallel to the interface plane and should not degrade electrical properties and device performance.
