The mode of a novel SiGe-OI optical waveguide is analyzed, and its single-mode conditions are derived. The Ge content and structure parameters of SiGe-OI optical waveguides are respectively optimized. Under an operati...The mode of a novel SiGe-OI optical waveguide is analyzed, and its single-mode conditions are derived. The Ge content and structure parameters of SiGe-OI optical waveguides are respectively optimized. Under an operation wavelength of 1300 nm, the structures of SiGe-OI rib optical waveguides are built and analyzed with Optiwave software, and the optical field and transmission losses of the SiGe-OI rib optical waveguides are analyzed. The optimization results show that when the structure parameters H, h, W are respectively 500 nm, 250 nm, 500 nm and the Ge content is 5%, the total power loss of SiGe-OI rib waveguides is 0.3683 dB/cm considering the loss of radiation outside the waveguides and materials, which is less than the traditional value of 0.5 dB/cm. The analytical technique for SiGe-OI optical waveguides and structure parameters computed by this paper are proved to be accurate and computationally efficient compared with the beam propagation method （BPM） and the experimental results.展开更多
It is important to acquire the composition of Si1-xGex layer, especially that with high Ge content, epitaxied on Si substrate. Two nondestructive examination methods, double crystals X-ray diffraction （DCXRD） and mi...It is important to acquire the composition of Si1-xGex layer, especially that with high Ge content, epitaxied on Si substrate. Two nondestructive examination methods, double crystals X-ray diffraction （DCXRD） and micro-Raman measurement, were introduced comparatively to determine x value in Si1-xGex layer, which show that while the two methods are consistent with each other when x is low, the results obtained from double crystals X-ray diffraction are not credible due to the large strain relaxation occurring in Si1-xGex layers when Ge content is higher than about 20%. Micro-Raman measurement is more appropriate for determining high Ge content than DCXRD.展开更多
SiGe single crystals with different Ge concentrations were measured by Fourier transform infrared （FTIR） spectroscopy at room temperature （RT） and 10 K. A new peak appears at the wave number of 710 cm^-1 and the s...SiGe single crystals with different Ge concentrations were measured by Fourier transform infrared （FTIR） spectroscopy at room temperature （RT） and 10 K. A new peak appears at the wave number of 710 cm^-1 and the spectroscopy becomes clearer with an increase in Ge content. The absorption strength and wave sharp of the 710 cm^-1 peak are independent of temperature. The relation of the absorption coefficient amax, the band width of half maximum （BWHM） Wit2 of the 710 cm^-1 peak, and the Ge concentration is determined with the Ge content obtained by SEM-EDX. The conversion factor is k = 1.211 at 10 K. Therefore, the Ge content in high concentration Ge doped CZ-Si single crystals can be determined by FTIR.展开更多
In this study,the growth kinetics of SiGe in a reduced pressure chemical vapor deposition system using dichlorosilane(SiH2Cl2) and germane(GeH4) as the Si and Ge precursors were investigated.The SiGe growth rate and G...In this study,the growth kinetics of SiGe in a reduced pressure chemical vapor deposition system using dichlorosilane(SiH2Cl2) and germane(GeH4) as the Si and Ge precursors were investigated.The SiGe growth rate and Ge content were found to depend on the deposition temperature,GeH4 flow and reactor chamber pressure.The SiGe growth rate escalates with increasing deposition temperature,while the Ge content is reduced.The SiGe growth rate accelerates with increasing GeH4 flow,while the Ge content increases more slowly.According to the experimental data,a new relationship between Ge content(x) and F(GeH4)/F(SiH2Cl2) mass flow ratio is deduced:x2.5/(1x) = nF(GeH4)/F(SiH2Cl2).The SiGe growth rate and Ge content improve with increasing reactor chamber pressure.By selecting proper precursor flows and reactor pressure,SiGe films with the same Ge content can be fabricated at various temperatures.However,the quality of the SiGe crystals is clearly dependent on the deposition temperature.At lower deposition temperature,higher crystalline quality is achieved.Because the growth rate dramatically drops with lower temperatures,the optimum growth temperature must be a compromise between the crystalline quality and the growth rate.X-ray diffraction,Raman scattering spectroscopy and atomic force microscopy results indicate that 650°C is the optimum temperature for fabrication of Si0.75Ge0.25 film.展开更多
基金supported by the Shenzhen Universitythe Open Fund Project of Province and Ministry Key Laboratory (No.2007002)
文摘The mode of a novel SiGe-OI optical waveguide is analyzed, and its single-mode conditions are derived. The Ge content and structure parameters of SiGe-OI optical waveguides are respectively optimized. Under an operation wavelength of 1300 nm, the structures of SiGe-OI rib optical waveguides are built and analyzed with Optiwave software, and the optical field and transmission losses of the SiGe-OI rib optical waveguides are analyzed. The optimization results show that when the structure parameters H, h, W are respectively 500 nm, 250 nm, 500 nm and the Ge content is 5%, the total power loss of SiGe-OI rib waveguides is 0.3683 dB/cm considering the loss of radiation outside the waveguides and materials, which is less than the traditional value of 0.5 dB/cm. The analytical technique for SiGe-OI optical waveguides and structure parameters computed by this paper are proved to be accurate and computationally efficient compared with the beam propagation method （BPM） and the experimental results.
基金This work is supported by the National Natural Science Foundation of China （Grant Nos. 60336010 ＆ 90401001）973 Program （Grant No. TG 2000036603）the Student Innovation Program of CAS （No. 1731000500010）.
文摘It is important to acquire the composition of Si1-xGex layer, especially that with high Ge content, epitaxied on Si substrate. Two nondestructive examination methods, double crystals X-ray diffraction （DCXRD） and micro-Raman measurement, were introduced comparatively to determine x value in Si1-xGex layer, which show that while the two methods are consistent with each other when x is low, the results obtained from double crystals X-ray diffraction are not credible due to the large strain relaxation occurring in Si1-xGex layers when Ge content is higher than about 20%. Micro-Raman measurement is more appropriate for determining high Ge content than DCXRD.
基金The work is financially supported by the National Natural Science Foundation of China (No. 59772037)the NaturalScience Foundation of Hebei Province, China (No. 500016).
文摘SiGe single crystals with different Ge concentrations were measured by Fourier transform infrared （FTIR） spectroscopy at room temperature （RT） and 10 K. A new peak appears at the wave number of 710 cm^-1 and the spectroscopy becomes clearer with an increase in Ge content. The absorption strength and wave sharp of the 710 cm^-1 peak are independent of temperature. The relation of the absorption coefficient amax, the band width of half maximum （BWHM） Wit2 of the 710 cm^-1 peak, and the Ge concentration is determined with the Ge content obtained by SEM-EDX. The conversion factor is k = 1.211 at 10 K. Therefore, the Ge content in high concentration Ge doped CZ-Si single crystals can be determined by FTIR.
基金supported by the National Natural Science Foundation of China (61006088)the National Basic Research Program of China(2010CB832906)the Natural Science Foundation of Shanghai(10ZR1436100)
文摘In this study,the growth kinetics of SiGe in a reduced pressure chemical vapor deposition system using dichlorosilane(SiH2Cl2) and germane(GeH4) as the Si and Ge precursors were investigated.The SiGe growth rate and Ge content were found to depend on the deposition temperature,GeH4 flow and reactor chamber pressure.The SiGe growth rate escalates with increasing deposition temperature,while the Ge content is reduced.The SiGe growth rate accelerates with increasing GeH4 flow,while the Ge content increases more slowly.According to the experimental data,a new relationship between Ge content(x) and F(GeH4)/F(SiH2Cl2) mass flow ratio is deduced:x2.5/(1x) = nF(GeH4)/F(SiH2Cl2).The SiGe growth rate and Ge content improve with increasing reactor chamber pressure.By selecting proper precursor flows and reactor pressure,SiGe films with the same Ge content can be fabricated at various temperatures.However,the quality of the SiGe crystals is clearly dependent on the deposition temperature.At lower deposition temperature,higher crystalline quality is achieved.Because the growth rate dramatically drops with lower temperatures,the optimum growth temperature must be a compromise between the crystalline quality and the growth rate.X-ray diffraction,Raman scattering spectroscopy and atomic force microscopy results indicate that 650°C is the optimum temperature for fabrication of Si0.75Ge0.25 film.
