The Experts below are selected from a list of 285 Experts worldwide ranked by ideXlab platform
Deren Yang - One of the best experts on this subject based on the ideXlab platform.
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Denuded Zone Formation in Germanium Codoped Heavily Phosphorus-Doped Czochralski Silicon
Chinese Physics Letters, 2011Co-Authors: Lixia Lin, Jiahe Chen, Yuheng Zeng, Deren YangAbstract: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.
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Internal gettering of copper contamination in Czochralski silicon
2010 10th IEEE International Conference on Solid-State and Integrated Circuit Technology, 2010Co-Authors: Lixia Lin, Jiahe Chen, Deren YangAbstract:The internal gettering (IG) of Cu contamination in Czochralski (Cz) silicon wafers has been investigated using both a conventional IG process based on high-low-high (H-L-H) annealing and a rapid-thermal-process (RTP) based magic Denuded Zone (MDZ) process. It is found that a Denuded Zone (DZ) and bulk micro-defects (BMDs) acting as the gettering sites were formed in both cases. However, after cross-sectional preferential etching of the Cu contaminated samples, the DZ disappeared in the conventional IG wafers but remained in the MDZ wafers. It is suggested that the DZ created by the conventional IG process actually contains small-sized BMDs that either survived the high temperature anneal or nucleated during the low temperature treatment. Accordingly, in terms of the formation of a better “clean” DZ, MDZ process is superior to the conventional IG process.
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Influence of nickel precipitation on the formation of Denuded Zone in Czochralski silicon
Journal of Alloys and Compounds, 2010Co-Authors: Yongzhi Wang, Deren Yang, H. J. MoellerAbstract:National Natural Science Foundation of China [50902116, 50832006]; Fujian Province University; State Key Laboratory of Silicon Materials, China [SKL2009-11]; Scientific and Technological Innovation Platform of Fujian Province, China [2009J1009]
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Oxygen precipitate Denuded Zone formation in Czochralski silicon wafer based on rapid thermal processing in nitrogen ambient
Semiconductor Science and Technology, 2007Co-Authors: Deren Yang, Hanqin Jiang, Duanlin QueAbstract:The effects of temperature and cooling rate of the rapid thermal processing (RTP) in N2 ambient on oxygen precipitation and the formation of Denuded Zone (DZ) in Czochralski (CZ) silicon subjected to a subsequent low–high (L–H) two-step annealing have been investigated. It is found that as long as the cooling process of the RTP in N2 ambient is sufficiently slow, the DZ can be definitely formed. Moreover, it is revealed that, with respect to the RTP in Ar ambient, the RTP in N2 ambient can be carried out at lower temperatures to achieve the comparable oxygen precipitation in the subsequent L–H two-step annealing, indicating that the internal gettering (IG) process for CZ silicon wafers can be based on the RTP in N2 ambient at lower temperatures.
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Influence of copper precipitation on the formation of Denuded Zone in Czochralski silicon
Journal of Applied Physics, 2007Co-Authors: Deren Yang, H. J. MoellerAbstract:The influence of copper precipitation on the formation of Denuded Zone (DZ) in Czochralski silicon was systematically investigated by means of scanning infrared microscopy (SIRM) and optical microscopy. It was found that, for conventional furnace high-low-high annealing, the DZ cannot be obtained only in the specimens contaminated by copper impurity at the very beginning of the heat treatment, indicating that the copper precipitates with high density generated in the region just below the surface during the first annealing step. Additionally, the width of the DZ changed according to the copper contamination sequence, indicating that the contamination temperature, that is, the corresponding equilibrium concentration of interstitial copper in the silicon, can influence significantly the thermodynamics and kinetic process of the formation of copper precipitates. For rapid thermal–low-high annealing, the tendency is nearly the same, while the contrast of the bulk microdefects revealed by SIRM is somewhat lowe...
Duanlin Que - One of the best experts on this subject based on the ideXlab platform.
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Oxygen precipitate Denuded Zone formation in Czochralski silicon wafer based on rapid thermal processing in nitrogen ambient
Semiconductor Science and Technology, 2007Co-Authors: Deren Yang, Hanqin Jiang, Duanlin QueAbstract:The effects of temperature and cooling rate of the rapid thermal processing (RTP) in N2 ambient on oxygen precipitation and the formation of Denuded Zone (DZ) in Czochralski (CZ) silicon subjected to a subsequent low–high (L–H) two-step annealing have been investigated. It is found that as long as the cooling process of the RTP in N2 ambient is sufficiently slow, the DZ can be definitely formed. Moreover, it is revealed that, with respect to the RTP in Ar ambient, the RTP in N2 ambient can be carried out at lower temperatures to achieve the comparable oxygen precipitation in the subsequent L–H two-step annealing, indicating that the internal gettering (IG) process for CZ silicon wafers can be based on the RTP in N2 ambient at lower temperatures.
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Denuded Zone in Czochralski silicon wafer with high carbon content
Journal of Physics: Condensed Matter, 2006Co-Authors: Jiahe Chen, Deren Yang, Duanlin QueAbstract:The thermal stability of the Denuded Zone (DZ) created by high?low?high-temperature annealing in high carbon content (H[C]) and low carbon content (L[C]) Czochralski silicon (Cz-Si) has been investigated in a subsequent ramping and isothermal 1050??C annealing. The tiny oxygen precipitates which might occur in the DZ were checked. It was found in the L[C] Cz-Si that the DZ shrank and the density of bulk micro-defects (BMDs) reduced with the increase of time spent at 1050??C. Also, the DZs above 15??m of thickness present in the H[C] Cz-Si wafers continuously and the density and total volume of BMDs first decreased then increased and finally decreased again during the treatments. Moreover, tiny oxygen precipitates were hardly generated inside the DZs, indicating that H[C] Cz-Si wafers could support the fabrication of integrated circuits.
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effect of nitrogen doping on Denuded Zone formed by rapid thermal process in czochralski silicon wafer
Physica B-condensed Matter, 2006Co-Authors: Can Cui, Deren Yang, Ruixin Fan, Duanlin QueAbstract:Abstract Denuded Zone (DZ) formed by rapid thermal process (RTP) followed with the low–high (Lo–Hi) annealing in nitrogen-doped Czochralski (NCZ) silicon wafer was studied in this paper. In comparison with the conventional CZ silicon, the DZ in NCZ silicon was a little narrower, while the bulk microdefects were much denser, as a result of nitrogen-enhanced oxygen precipitation. It was also found that DZs within CZ and NCZ silicon wafers shrunk notably when further subjected to rigorous oxygen precipitation annealing, however, a width of substantial DZ remained within either wafer. Furthermore, it is definitely proved that the nitrogen doping does not affect the formation of defect-free DZ by the RTP-based internal gettering (IG) process.
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Effect of annealing atmosphere on oxygen precipitation and formation of Denuded Zone in Czochralski silicon wafer
physica status solidi (a), 2006Co-Authors: Can Cui, Deren Yang, Ruixin Fan, Duanlin QueAbstract:In this paper, the effect of annealing atmosphere on oxygen precipitation and formation of Denuded Zone (DZ) in Czochralski (CZ) silicon has been investigated. It was revealed that the high-temperature annealings in various atmospheres resulted in almost identical oxygen outdiffusion length but different widths of DZ in the silicon wafers. It was confirmed that the high-temperature annealing in nitrogen atmosphere induced a high concentration of vacancies in silicon to enhance oxygen precipitation, while the annealing in oxidizing atmosphere or steam-mixed atmosphere induced a high concentration of silicon self-interstitials to retard oxygen precipitation. Moreover, it was confirmed that the steam mixed into the nitrogen atmosphere could suppress the indiffusion of nitrogen atoms. (© 2006 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)
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Effect of nitrogen on Denuded Zone in Czochralski silicon wafer
Semiconductor Science and Technology, 2004Co-Authors: Can Cui, Deren Yang, Duanlin QueAbstract:The effect of nitrogen on the Denuded Zone (DZ) in Czochralski CZ silicon has been investigated. After the DZ formation, the CZ and the nitrogen-doped CZ (NCZ) silicon wafers were subjected to prolonged annealing. It is found that the DZ of the NCZ silicon only shrinks a little during the prolonged annealing, and no new oxygen precipitates are formed in the DZ, which is the same as the corresponding CZ wafer. Therefore, it is considered that no tiny oxygen precipitates existed in the DZ of the NCZ-Si by IG treatment, which can satisfy the requirements of microelectronics industry. Based on the facts, the effect mechanism of nitrogen on the DZ is discussed.
Can Cui - One of the best experts on this subject based on the ideXlab platform.
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Effects of two-step rapid thermal processing in different ambients on Denuded Zone and oxygen precipitation in Czochralski silicon
physica status solidi (c), 2007Co-Authors: Deren Yang, Can Cui, An. Duanlin QueAbstract:The effects of two-step rapid thermal processing (RTP) sequentially in different ambients on the formation of Denuded Zone (DZ) and oxygen precipitation in the Czochralski (CZ) silicon wafers have been investigated. With the first-step RTP in Ar ambient, no obvious DZ but a high density of bulk micro-defects (BMDs) were formed in the sample with the second-step RTP in N2 ambient, while the BMD density in the sample with the second-step RTP in O2 ambient was remarkably low. With the first-step RTP in N2 ambient, a high density of BMDs and a width of DZ could be formed in either of the samples with the second-step RTP in Ar or O2 ambient, but the DZ width in the two samples differed to a certain extent. With the first-step RTP in O2 ambient, the two samples with the second-step RTP in Ar and N2 ambients respectively possessed reasonably comparable DZ width and BMD density. (© 2007 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)
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effect of nitrogen doping on Denuded Zone formed by rapid thermal process in czochralski silicon wafer
Physica B-condensed Matter, 2006Co-Authors: Can Cui, Deren Yang, Ruixin Fan, Duanlin QueAbstract:Abstract Denuded Zone (DZ) formed by rapid thermal process (RTP) followed with the low–high (Lo–Hi) annealing in nitrogen-doped Czochralski (NCZ) silicon wafer was studied in this paper. In comparison with the conventional CZ silicon, the DZ in NCZ silicon was a little narrower, while the bulk microdefects were much denser, as a result of nitrogen-enhanced oxygen precipitation. It was also found that DZs within CZ and NCZ silicon wafers shrunk notably when further subjected to rigorous oxygen precipitation annealing, however, a width of substantial DZ remained within either wafer. Furthermore, it is definitely proved that the nitrogen doping does not affect the formation of defect-free DZ by the RTP-based internal gettering (IG) process.
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Effect of annealing atmosphere on oxygen precipitation and formation of Denuded Zone in Czochralski silicon wafer
physica status solidi (a), 2006Co-Authors: Can Cui, Deren Yang, Ruixin Fan, Duanlin QueAbstract:In this paper, the effect of annealing atmosphere on oxygen precipitation and formation of Denuded Zone (DZ) in Czochralski (CZ) silicon has been investigated. It was revealed that the high-temperature annealings in various atmospheres resulted in almost identical oxygen outdiffusion length but different widths of DZ in the silicon wafers. It was confirmed that the high-temperature annealing in nitrogen atmosphere induced a high concentration of vacancies in silicon to enhance oxygen precipitation, while the annealing in oxidizing atmosphere or steam-mixed atmosphere induced a high concentration of silicon self-interstitials to retard oxygen precipitation. Moreover, it was confirmed that the steam mixed into the nitrogen atmosphere could suppress the indiffusion of nitrogen atoms. (© 2006 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)
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Effect of nitrogen on Denuded Zone in Czochralski silicon wafer
Semiconductor Science and Technology, 2004Co-Authors: Can Cui, Deren Yang, Duanlin QueAbstract:The effect of nitrogen on the Denuded Zone (DZ) in Czochralski CZ silicon has been investigated. After the DZ formation, the CZ and the nitrogen-doped CZ (NCZ) silicon wafers were subjected to prolonged annealing. It is found that the DZ of the NCZ silicon only shrinks a little during the prolonged annealing, and no new oxygen precipitates are formed in the DZ, which is the same as the corresponding CZ wafer. Therefore, it is considered that no tiny oxygen precipitates existed in the DZ of the NCZ-Si by IG treatment, which can satisfy the requirements of microelectronics industry. Based on the facts, the effect mechanism of nitrogen on the DZ is discussed.
Tien-ko Wang - One of the best experts on this subject based on the ideXlab platform.
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Effects of interstitial oxygen defects at HfO/sub x/N/sub y//Si interface on electrical characteristics of MOS devices
IEEE Transactions on Electron Devices, 2006Co-Authors: Chin-lung Cheng, Kuei-shu Chang-liao, Ching-hung Huang, Sheng-hung Wang, Tien-ko WangAbstract:Effects of the defects at high-/spl kappa/ dielectric/Si interface on the electrical characteristics of MOS devices are important issues. To study these issues, a low defect (Denuded Zone) at Si surface was formed by a high-temperature annealing in hydrogen atmosphere in this paper. Our results reveal that HfO/sub x/N/sub y/ demonstrates significant improvement on the electrical properties of MOS devices due to its low amount of the interstitial oxygen [O/sub i/] and the crystal-originated particles defects as well as small surface roughness at HfO/sub x/N/sub y//Si interface. The current-conduction mechanism of the HfO/sub x/N/sub y/ film at the low- and high-electrical field and high-temperature (T>100/spl deg/C) is dominated by Schottky emission and Frenkel-Poole (FP) emission, respectively. The trap energy level involved in FP conduction was estimated to be around 0.5eV. Reduced gate leakage current, stress-induced leakage current and defect generation rate, attributable to the reduction of defects at HfO/sub x/N/sub y//Si interface, were observed for devices with Denuded Zone. The variable rise and fall time bipolar-pulse-induced current technique was used to determine the energy distribution of interface trap density (D/sub it/). The results exhibit that relatively low D/sub it/ can be attributed to the reduction of defects at Si surface. By using Denuded Zone at the Si surface, HfO/sub x/N/sub y/ has demonstrated significant improvement on electrical properties as compared to SiO/sub x/N/sub y/.
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Effects of Denuded Zone of Si(111) surface on current conduction and charge trapping of HfOxNy gate dielectric in metal-oxide-semiconductor devices
Applied Physics Letters, 2004Co-Authors: Chin-lung Cheng, Kuei-shu Chang-liao, Ching-hung Huang, Tien-ko WangAbstract:This work investigated the effects of interstitial oxygen [Oi] defects at the Si(111) surface on current conduction and charge trapping of metal-oxide-simiconductor devices with HfOxNy gate dielectric. Smaller gate leakage current, stress-induced leakage current (SILC) and defect generation rate, attributable to the decrease of [Oi] defect concentration at the HfOxNy∕Si interface, were observed for devices with Denuded Zone. The current-conduction mechanism of the HfOxNy films at the low- and high-electrical field was dominated by the Schottky and Frenkel–Poole emissions, respectively. The trapped charges in HfOxNy dielectric were positive. The mechanism related to the SILC at low-electrical field can be explained using the interface trap-assisted tunneling.
F. Cazzaniga - One of the best experts on this subject based on the ideXlab platform.
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Denuded Zone and diffusion length investigation by electron beam induced current technique in intrinsically gettered Czochralski silicon
Journal of Applied Physics, 1999Co-Authors: Sabina Spiga, M.l. Polignano, Antonio Castaldini, Anna Cavallini, F. CazzanigaAbstract:Electron beam induced current (EBIC) technique is successfully used to characterize intrinsically gettered Czochralski silicon. The impact of three different sequences of thermal treatments, typically used in ultralarge scale integration device manufacturing, on the Denuded Zone (DZ) formation and oxygen precipitation in the bulk is evaluated. EBIC technique is applied in a nonstandard configuration, where a Schottky diode is evaporated on the wafer cross section, for the direct observation of the DZ and oxygen related defects in the silicon bulk. The reduction of minority carrier diffusion length, due to the formation of recombination centers after oxygen precipitation, is also estimated by EBIC in planar collector geometry. The DZ determination by EBIC technique is in good agreement with surface photovoltage measurements and microscopical inspections after chemical etching.
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Denuded Zone Thickness from Surface Photovoltage Measurements Comparison with Microscopy Techniques
Journal of The Electrochemical Society, 1998Co-Authors: M.l. Polignano, M. Brambilla, F. Cazzaniga, G. Pavia, F. ZanderigoAbstract:A method for measuring Denuded Zone depth from lifetime measurements is proposed and compared to observations by microscopy techniques. The surface photovoltage (SPV) method is chosen for measuring lifetime, as it is found to be extremely sensitive to oxygen precipitation. SPV estimates of Denuded Zone depth are compared to observations by microscopy techniques, such as selective etching and inspections by a scanning electron microscope or an atomic force microscope, and analysis by transmission electron microscopy. SPV estimates agree with microscopy inspection, provided defect density is high enough to allow a Denuded Zone to be identified.
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Evaluating the Denuded Zone Depth by Measurements of the Recombination Activity of Bulk Defects
MRS Proceedings, 1998Co-Authors: M.l. Polignano, M. Brambilla, F. Cazzaniga, G. Pavia, F. Zanderigo, Sabina Spiga, L. Moro, Antonio Castaldini, Anna CavalliniAbstract:AbstractA method for measuring Denuded Zone depth from lifetime measurements is proposed and compared to observations by microscopy techniques and to Electron Beam Induced Current (EBIC) analyses. The surface photovoltage (SPV) method is chosen for measuring lifetime, as it is found to be extremely sensitive to oxygen precipitation. Samples prepared according to three typical thermal hystories are used as test vehicles.Correlating the results given by the different techniques, this study points out a few relevant features from the point of view of wafer processing. For instance, processes starting with a low temperature treatment are poorly reproducible for what concerns oxygen precipitation and denuding, as shown by SPV data, and do not guarantee a defect-free Denuded Zone, as seen in EBIC images. Additional high temperature treatments during the process increase the Denuded Zone depth and improve uniformity.Techniques which rely on a selective etching for defect detection, such as the Secondary Electron method of Scanning Electron Microscopy (SEM) and Atomic Force Microscopy (AFM), are limited by etching sensitivy. On the other hand, the Transmission Electron Microscopy (TEM) statistics is too poor for this sort of observations. Instead, as a technique based on the recombination activity of defects, EBIC has roughly the same sensitivity as SPV. Both these techniques detect the formation of a Denuded Zone even when other methods fail, and can be considered as complementary tools.