Papers by Keyword: Silicon Crystal

Abstract: To investigate the growth dynamics of the single void during Czochralski silicon growth as well as capture the basic features of the diffusion-controlled dynamic mechanisms, a phase field method has been developed. The free energy of the system involving the chemical free energy and the gradient energy is presented. Numerical tests were performed to examine the capability of this model, and the results show that: the void grows due to the absorption of vacancies in the matrix, which essentially reduces the free energy of the system; with the growth of the void, there forms vacancy concentration gradient towards the void in the matrix; the increase of initial vacancy concentration contributes to a larger void size and growth rate.

Abstract: In 1895, Dr. Wilhelm Conrad Röentgen discovered the electromagnetic radiation called X-rays. Since the great finding, the applications of X-ray imaging have expanded. One of most important application is medical use, such as imaging diagnosis or radiation therapy. Also, applications of X-ray are based on the strong interactions with materials including transmission, absorption, diffraction, reflection, scattering, and emission. Today, X-ray imaging is applied to more delicate medical and life sciences, as well as basic sciences, because it is needed for its brilliance, power, and coherence. [1-6]

Abstract: We consider a bulk silicon crystal as a Mid-IR Raman amplifier and study its Raman amplification. A Raman amplifier is established when an intense pump laser pulse and a Raman laser pulse pass through one silicon simultaneously, with good spatial and temporal overlap. Considering the situation of pumping wavelength at 2.94 μm achievable by using an Er:YAG laser and Raman laser wavelength at 3.47 μm with the 521 cm-1 Raman shift, the properties of the output amplified Raman laser are investigated by numerically solving the coupled transfer equations.

Abstract: In order to investigate the performance of silicon single crystal depended on the annealing temperature, the minority carrier lifetime, the resistivity and oxygen concentration after different temperature annealing in Ar ambient were examined. And the effect of oxygen and related defects formed during annealed on the minority carrier lifetime were analyzed by microwave photoconductivity method, Fourier transform infrared spectrometer and four-probe measurement. The results indicate that after 450°C annealing for 30h, the resistivity and minority carrier lifetime of silicon increase significantly, while the concentration of interstitial oxygen decreases. After the annealing at 650°C, oxygen donor can be removed and the resistivity and the minority carrier lifetime decrease. During the high-temperature (above 650°C) annealing, the oxygen precipitation can decrease the minority carrier lifetime silicon.

Abstract: Silicon wafers with different carbon contents have been characterized by Fourier transform infrared spectroscopy technique. An infrared absorption band at 1207cm-1 can be newly observed in the case of carbon content being above 1.7×1017/cm3, whose intensity increases with an increase of carbon concentration in silicon crystal. More interestingly, the 1207cm-1 band cannot be influenced by the long-time annealing in the temperature range of 450-1250oC, suggesting the high thermal stability of this carbon-related defect, which might be related to the presence of silicon carbide in silicon crystals.