By indentation at room temperature followed by annealing at high temperatures, the pinning effect of germanium on dislocations in germanium-doped Czochralski silicon was investigated. Experimental results show that th...By indentation at room temperature followed by annealing at high temperatures, the pinning effect of germanium on dislocations in germanium-doped Czochralski silicon was investigated. Experimental results show that the dislocations in germanium-doped Czochralski silicon move shorter and slower than those in Czochralski silicon undoping with germanium when the concentration of germanium is over 1×1018 cm-3. The retarding velocity of dislocations is contributed to the dislocations pinning effect of the strain field introduced by the high concentration germanium, and the Ge4B cluster and the oxygen precipitation those are preferred to form at higher concentration germanium.展开更多
In this research KCl, KCl:Mn, KCl:Ag and KCl:In single crystals have been grown by Czochralski method. X-ray diffraction confirms KCl single crystal formation. In this work also influence of mentioned impurities on th...In this research KCl, KCl:Mn, KCl:Ag and KCl:In single crystals have been grown by Czochralski method. X-ray diffraction confirms KCl single crystal formation. In this work also influence of mentioned impurities on the optical property of KCl single crystal has been studied by chemical etching. Then the hardness of these crystals have been measured by Vickers micro hardness. The result indicate the positive effect of the impurity on optical and mechanical properties.展开更多
The morphology and microstructure of flow pattern defects (FPDs) in lightly boron-doped Czochralski-grown silicon (Cz-Si) crystals were investigated using optical microscopy and atomic force microscopy. The experiment...The morphology and microstructure of flow pattern defects (FPDs) in lightly boron-doped Czochralski-grown silicon (Cz-Si) crystals were investigated using optical microscopy and atomic force microscopy. The experimental results showed that the morphology of FPDs was parabola-like with several steps. Single-type and dual-type voids were found on the tip of FPDs and two heaves exist on the left and right sides of the void. All the results have proved that FPDs were void-type defects. These results are very useful to investigate FPDs in Cz-Si wafers further and explain the annihilation of FPDs during high-temperature annealing.展开更多
A mechanism of oxygen transportation in Czochralski growth of silicon crystals under a horizontal magnetic field(HMCZ)is proposed.Oxygen depleted surface melt,driven to the growth interface by the thermal Marangoni fl...A mechanism of oxygen transportation in Czochralski growth of silicon crystals under a horizontal magnetic field(HMCZ)is proposed.Oxygen depleted surface melt,driven to the growth interface by the thermal Marangoni flow.determines oxygenconcentration in the grown crystals.Systematic study was carried out to investigate effects of growth parameters on oxygen in-corporation into crystals.展开更多
Fast-neutron irradiated nitrogen-doped Czochralski silicon (NCZ-Si) was annealed at 1100 ℃ for different time, then FTIR and optical microscope were used to study the behavior of oxygen. It is found that [Oi] increas...Fast-neutron irradiated nitrogen-doped Czochralski silicon (NCZ-Si) was annealed at 1100 ℃ for different time, then FTIR and optical microscope were used to study the behavior of oxygen. It is found that [Oi] increase at the early stage then decrease along with the increasing of anneal time. High density induced-defects can be found in the cleavage plane. By comparing NCZ-Si with Czochralski silicon (CZ-Si), [Oi] in NCZ-Si decrease more after anneal 24 h.展开更多
The zinc oxide seed film was coated on conductive glass (FTO) substrate by the Czochralski method,Zinc acetate and hexamethylenetetramine were used as raw materials to prepare growth solution,and then ZnO film was pre...The zinc oxide seed film was coated on conductive glass (FTO) substrate by the Czochralski method,Zinc acetate and hexamethylenetetramine were used as raw materials to prepare growth solution,and then ZnO film was prepared by a low-temperature solution method.The effects of annealing temperature on the morphology,structure,stress and optical properties of ZnO films were studied.The thin films were characterized by X-ray diffraction (XRD),scanning electron microscopy (SEM),UV-visible absorption spectra (UV-vis),photoluminescence (PL) and X-ray photoelectron spectroscopy (XPS).The results show that the films are ZnO nanorods.With the increase of annealing temperature,the diameter of the rod increases,and the nanorods tend to be oriented.The band gap of the sample obtained from the light absorption spectra first increases and then decreases with the increase of annealing temperature.When the annealing temperature is 350 ℃,the crystallinity of zinc oxide film is the highest,the band gap is close to the theoretical value of pure ZnO.展开更多
Electrical activity of Frank partial dislocations bounding stacking faults and the influence of Fe impurities in Czochralski-grown silicon are investigated by means of the electron-beam-induced-current(EBIC)technique....Electrical activity of Frank partial dislocations bounding stacking faults and the influence of Fe impurities in Czochralski-grown silicon are investigated by means of the electron-beam-induced-current(EBIC)technique.Frank partials free from metallic impurities exhibit EBIC contrast at low temperature but not at room temperature,indicating that they are only accompanied with shallow energy levels in the band gap.The energy level related to a Frank partial is determined to be about Ec-0.08eV in n-type Si.Frank partials decorated by Fe impurities become EBIC active at room temperature.展开更多
The formation of a denuded zone(DZ)by conventional furnace annealing(CFA)and rapid thermal annealing(RTA)based denudation processing is investigated and the gettering of copper(Cu)atoms in germanium co-doped heavily p...The formation of a denuded zone(DZ)by conventional furnace annealing(CFA)and rapid thermal annealing(RTA)based denudation processing is investigated and the gettering of copper(Cu)atoms in germanium co-doped heavily phosphorus-doped Czochralski(GHPCZ)silicon wafers is evaluated.It is suggested that both a good quality defect-free DZ with a suitable width in the sub-surface area and a high density bulk micro-defect(BMD)region could be formed in heavily phosphorus-doped Czochralski(HPCZ)silicon and GHPCZ silicon wafers.This is ascribed to the formation of phosphorus-vacancy(P-V)related complexes and germanium-vacancy(GeV)related complexes.Compared with HPCZ silicon,the DZ width is wider in the GHPCZ silicon sample with CFA-based denudation processing but narrower in the one with two-step RTA pretreatments.These phenomena are ascribed to the enhancing effect of germanium on oxygen out-diffusion movement and oxygen precipitate nucleation,respectively.Furthermore,fairly clean DZs near the surface remain in both the HPCZ and GHPCZ silicon wafers after Cu in-diffusion,except for the HPCZ silicon wafer which underwent denudation processing with a CFA pretreatment,suggesting that germanium doping could improve the gettering of Cu contamination.展开更多
Resistivity, magnetoresistivity and Hall effect measurements in n-type Te-doped InSb and S-doped InAs samples grown by the liquid encapsulated Czochralski technique were carried out as a function of temperature (14-35...Resistivity, magnetoresistivity and Hall effect measurements in n-type Te-doped InSb and S-doped InAs samples grown by the liquid encapsulated Czochralski technique were carried out as a function of temperature (14-350K) and magnetic field (0-1.35 T). In Te-doped InSb, an impurity level with energy E1 = 3 meV and the activation energy E0 = 0.26 eV, which is the band gap energy, are obtained from the resistivity and Hall carrier concentration analysis. In S-doped InAs, both the linear and power law models are used in explaining the temperature-dependent resistivity. The effects of impurities on the electron and magnetic transportation properties of InAs and InSb have also been discussed.展开更多
A numerical study was carried out to describe the flow field structure of an oxide melt under 1) the effect of internal radiation through the melt (and the crystal), and 2) the impact of surface tension-driven forces ...A numerical study was carried out to describe the flow field structure of an oxide melt under 1) the effect of internal radiation through the melt (and the crystal), and 2) the impact of surface tension-driven forces during Czochralski growth process. Throughout the present Finite Volume Method calculations, the melt is a Boussinnesq fluid of Prandtl number 4.69 and the flow is assumed to be in a steady, axisymmetric state. Particular attention is paid to an undulating structure of buoyancy-driven flow that appears in optically thick oxide melts and persists over against forced convection flow caused by the externally imposed rotation of the crystal. In a such wavy pattern of the flow, particularly for a relatively higher Rayleigh number , a small secondary vortex appears nearby the crucible bottom. The structure of the vortex which has been observed experimentally is studied in some details. The present model analysis discloses that, though both of the mechanisms 1) and 2) end up in smearing out the undulating structure of the flow, the effect of thermocapillary forces on the flow pattern is distinguishably different. It is shown that for a given dynamic Bond number, the behavior of the melt is largely modified. The transition corresponds to a jump discontinuity in the magnitude of the flow stream function.展开更多
μ-Czochralski technique has been analyzed using two-dimensional crystallization simulator. It is observed that the temperature is relatively uniform in the entire Si region after the laser irradiation because the hea...μ-Czochralski technique has been analyzed using two-dimensional crystallization simulator. It is observed that the temperature is relatively uniform in the entire Si region after the laser irradiation because the heat conductivity of the Si region is much higher than that of the underneath SiO2. Grain growth advances from the grain filter to the channel region and continues until it collides with what advances from random nucleation in the channel region. When the initial temperature is high, the random nucleation rarely occurs even under the supercooling condition, and the grain size becomes large. Moreover, it is qualitatively reproduced that the grain size increases as the irradiated energy of the laser irradiation increases.展开更多
Further development of the photovoltaic industry is restricted by the productivity of mono-crystalline silicon technology due to its requirements of low cost and high efficient photocells.The heat shield is not only t...Further development of the photovoltaic industry is restricted by the productivity of mono-crystalline silicon technology due to its requirements of low cost and high efficient photocells.The heat shield is not only the important part of the thermal field in Czochralski(Cz)mono-crystalline silicon furnace,but also one of the most important factors influencing the silicon crystal growth.Large-diameter Cz-Si crystal growth process is taken as the study object.Based on FEM numerical simulation,different heat shield structures are analyzed to investigate the heater power,the melt-crystal interface shape,the argon flow field,and the oxygen concentration at the melt-crystal interface in the process of large Cz-Si crystal growth.The impact of these factors on the growth efficiency and crystal quality are analyzed.The results show that the oxygen concentration on the melt-crystal interface and the power consumption of the heater stay high due to the lack of a heat shield in the crystal growth system.Argon circumfluence is generated on the external side of the right angle heat shield.By the right-angle heat shield,the speed of gas flow is lowered on the melt free surface,and the temperature gradient of the free surface is increased around the melt-crystal interface.It is not conducive for the stable growth of crystal.The shape of the melt-crystal interface and the argon circulation above the melt free surface are improved by the inclined heat shield.Compared with the others,the system pulling rate is increased and the lowest oxygen concentration is achieved at the melt-crystal interface with the composite heat shield.By the adoption of the optimized composite heat shield in experiment,the real melt-crystal interface shapes and its deformation laws obtained by Quick Pull Separation Method at different pulling rates agree with the simulation results.The results show that the method of simulation is feasible.The proposed research provides the theoretical foundation for the thermal field design of the large diameter Cz-Si monocrystalline growth.展开更多
Simulations of heat transfer and oxygen transport during a Czochralski growth of silicon with and without a cusp magnetic field were carried out. A finite volume method with a low-Reynolds number K-ε model proposed b...Simulations of heat transfer and oxygen transport during a Czochralski growth of silicon with and without a cusp magnetic field were carried out. A finite volume method with a low-Reynolds number K-ε model proposed by Jones-Launder was employed. The numerical results were compared with the experimental data in the literature. It is found that the calculated results are in good agreement with the experimental data.展开更多
基金Project supported by the National Natural Science Foundation of China (50032010 and 60225010)
文摘By indentation at room temperature followed by annealing at high temperatures, the pinning effect of germanium on dislocations in germanium-doped Czochralski silicon was investigated. Experimental results show that the dislocations in germanium-doped Czochralski silicon move shorter and slower than those in Czochralski silicon undoping with germanium when the concentration of germanium is over 1×1018 cm-3. The retarding velocity of dislocations is contributed to the dislocations pinning effect of the strain field introduced by the high concentration germanium, and the Ge4B cluster and the oxygen precipitation those are preferred to form at higher concentration germanium.
文摘In this research KCl, KCl:Mn, KCl:Ag and KCl:In single crystals have been grown by Czochralski method. X-ray diffraction confirms KCl single crystal formation. In this work also influence of mentioned impurities on the optical property of KCl single crystal has been studied by chemical etching. Then the hardness of these crystals have been measured by Vickers micro hardness. The result indicate the positive effect of the impurity on optical and mechanical properties.
基金This work was financially supported by the National Natural Science Foundation of China (No. 60076001 and No.50032010), the Natural Science Foundation of Tianjin (No. 043602511) and the Natural Science Foundation of Hebei Province of China (No. E2005000057).
文摘The morphology and microstructure of flow pattern defects (FPDs) in lightly boron-doped Czochralski-grown silicon (Cz-Si) crystals were investigated using optical microscopy and atomic force microscopy. The experimental results showed that the morphology of FPDs was parabola-like with several steps. Single-type and dual-type voids were found on the tip of FPDs and two heaves exist on the left and right sides of the void. All the results have proved that FPDs were void-type defects. These results are very useful to investigate FPDs in Cz-Si wafers further and explain the annihilation of FPDs during high-temperature annealing.
文摘A mechanism of oxygen transportation in Czochralski growth of silicon crystals under a horizontal magnetic field(HMCZ)is proposed.Oxygen depleted surface melt,driven to the growth interface by the thermal Marangoni flow.determines oxygenconcentration in the grown crystals.Systematic study was carried out to investigate effects of growth parameters on oxygen in-corporation into crystals.
基金Project supported by the National Nature Science Foundation of China (50472034), the Natural Science Foundation of Hebei Province (E2005000048) and Education Ministry Doctoral Program Foundation of China (20050080006)
文摘Fast-neutron irradiated nitrogen-doped Czochralski silicon (NCZ-Si) was annealed at 1100 ℃ for different time, then FTIR and optical microscope were used to study the behavior of oxygen. It is found that [Oi] increase at the early stage then decrease along with the increasing of anneal time. High density induced-defects can be found in the cleavage plane. By comparing NCZ-Si with Czochralski silicon (CZ-Si), [Oi] in NCZ-Si decrease more after anneal 24 h.
基金Funded by Henan International Science and Technology Cooperation Program (No.152102410035)Ph D Research Startup Foundation of Henan University of Science and Technology(No.13480107)。
文摘The zinc oxide seed film was coated on conductive glass (FTO) substrate by the Czochralski method,Zinc acetate and hexamethylenetetramine were used as raw materials to prepare growth solution,and then ZnO film was prepared by a low-temperature solution method.The effects of annealing temperature on the morphology,structure,stress and optical properties of ZnO films were studied.The thin films were characterized by X-ray diffraction (XRD),scanning electron microscopy (SEM),UV-visible absorption spectra (UV-vis),photoluminescence (PL) and X-ray photoelectron spectroscopy (XPS).The results show that the films are ZnO nanorods.With the increase of annealing temperature,the diameter of the rod increases,and the nanorods tend to be oriented.The band gap of the sample obtained from the light absorption spectra first increases and then decreases with the increase of annealing temperature.When the annealing temperature is 350 ℃,the crystallinity of zinc oxide film is the highest,the band gap is close to the theoretical value of pure ZnO.
文摘Electrical activity of Frank partial dislocations bounding stacking faults and the influence of Fe impurities in Czochralski-grown silicon are investigated by means of the electron-beam-induced-current(EBIC)technique.Frank partials free from metallic impurities exhibit EBIC contrast at low temperature but not at room temperature,indicating that they are only accompanied with shallow energy levels in the band gap.The energy level related to a Frank partial is determined to be about Ec-0.08eV in n-type Si.Frank partials decorated by Fe impurities become EBIC active at room temperature.
基金Supported by the National Natural Science Foundation of China under Grant Nos 50832006 and 60906001the National Basic Research Program of China under Grant No 2007CB6130403,and the China Postdoctoral Science Foundation.
文摘The formation of a denuded zone(DZ)by conventional furnace annealing(CFA)and rapid thermal annealing(RTA)based denudation processing is investigated and the gettering of copper(Cu)atoms in germanium co-doped heavily phosphorus-doped Czochralski(GHPCZ)silicon wafers is evaluated.It is suggested that both a good quality defect-free DZ with a suitable width in the sub-surface area and a high density bulk micro-defect(BMD)region could be formed in heavily phosphorus-doped Czochralski(HPCZ)silicon and GHPCZ silicon wafers.This is ascribed to the formation of phosphorus-vacancy(P-V)related complexes and germanium-vacancy(GeV)related complexes.Compared with HPCZ silicon,the DZ width is wider in the GHPCZ silicon sample with CFA-based denudation processing but narrower in the one with two-step RTA pretreatments.These phenomena are ascribed to the enhancing effect of germanium on oxygen out-diffusion movement and oxygen precipitate nucleation,respectively.Furthermore,fairly clean DZs near the surface remain in both the HPCZ and GHPCZ silicon wafers after Cu in-diffusion,except for the HPCZ silicon wafer which underwent denudation processing with a CFA pretreatment,suggesting that germanium doping could improve the gettering of Cu contamination.
文摘Resistivity, magnetoresistivity and Hall effect measurements in n-type Te-doped InSb and S-doped InAs samples grown by the liquid encapsulated Czochralski technique were carried out as a function of temperature (14-350K) and magnetic field (0-1.35 T). In Te-doped InSb, an impurity level with energy E1 = 3 meV and the activation energy E0 = 0.26 eV, which is the band gap energy, are obtained from the resistivity and Hall carrier concentration analysis. In S-doped InAs, both the linear and power law models are used in explaining the temperature-dependent resistivity. The effects of impurities on the electron and magnetic transportation properties of InAs and InSb have also been discussed.
基金supported by the National Natural Science Foundation of China(NSFC)under grant No.50376078the Second-Term National 985 Project within Research Center of Biological Function Information and Instruments of Chongqing University.
文摘A numerical study was carried out to describe the flow field structure of an oxide melt under 1) the effect of internal radiation through the melt (and the crystal), and 2) the impact of surface tension-driven forces during Czochralski growth process. Throughout the present Finite Volume Method calculations, the melt is a Boussinnesq fluid of Prandtl number 4.69 and the flow is assumed to be in a steady, axisymmetric state. Particular attention is paid to an undulating structure of buoyancy-driven flow that appears in optically thick oxide melts and persists over against forced convection flow caused by the externally imposed rotation of the crystal. In a such wavy pattern of the flow, particularly for a relatively higher Rayleigh number , a small secondary vortex appears nearby the crucible bottom. The structure of the vortex which has been observed experimentally is studied in some details. The present model analysis discloses that, though both of the mechanisms 1) and 2) end up in smearing out the undulating structure of the flow, the effect of thermocapillary forces on the flow pattern is distinguishably different. It is shown that for a given dynamic Bond number, the behavior of the melt is largely modified. The transition corresponds to a jump discontinuity in the magnitude of the flow stream function.
文摘μ-Czochralski technique has been analyzed using two-dimensional crystallization simulator. It is observed that the temperature is relatively uniform in the entire Si region after the laser irradiation because the heat conductivity of the Si region is much higher than that of the underneath SiO2. Grain growth advances from the grain filter to the channel region and continues until it collides with what advances from random nucleation in the channel region. When the initial temperature is high, the random nucleation rarely occurs even under the supercooling condition, and the grain size becomes large. Moreover, it is qualitatively reproduced that the grain size increases as the irradiated energy of the laser irradiation increases.
基金Supported by National Natural Science Foundation of China(Grant Nos.61075044,F0304)
文摘Further development of the photovoltaic industry is restricted by the productivity of mono-crystalline silicon technology due to its requirements of low cost and high efficient photocells.The heat shield is not only the important part of the thermal field in Czochralski(Cz)mono-crystalline silicon furnace,but also one of the most important factors influencing the silicon crystal growth.Large-diameter Cz-Si crystal growth process is taken as the study object.Based on FEM numerical simulation,different heat shield structures are analyzed to investigate the heater power,the melt-crystal interface shape,the argon flow field,and the oxygen concentration at the melt-crystal interface in the process of large Cz-Si crystal growth.The impact of these factors on the growth efficiency and crystal quality are analyzed.The results show that the oxygen concentration on the melt-crystal interface and the power consumption of the heater stay high due to the lack of a heat shield in the crystal growth system.Argon circumfluence is generated on the external side of the right angle heat shield.By the right-angle heat shield,the speed of gas flow is lowered on the melt free surface,and the temperature gradient of the free surface is increased around the melt-crystal interface.It is not conducive for the stable growth of crystal.The shape of the melt-crystal interface and the argon circulation above the melt free surface are improved by the inclined heat shield.Compared with the others,the system pulling rate is increased and the lowest oxygen concentration is achieved at the melt-crystal interface with the composite heat shield.By the adoption of the optimized composite heat shield in experiment,the real melt-crystal interface shapes and its deformation laws obtained by Quick Pull Separation Method at different pulling rates agree with the simulation results.The results show that the method of simulation is feasible.The proposed research provides the theoretical foundation for the thermal field design of the large diameter Cz-Si monocrystalline growth.
基金Supported by the Ph.D. Start-up Fund of Beijing University of Technology (No.127-00227).
文摘Simulations of heat transfer and oxygen transport during a Czochralski growth of silicon with and without a cusp magnetic field were carried out. A finite volume method with a low-Reynolds number K-ε model proposed by Jones-Launder was employed. The numerical results were compared with the experimental data in the literature. It is found that the calculated results are in good agreement with the experimental data.
