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A Rohatgi - One of the best experts on this subject based on the ideXlab platform.
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review and comparison of equations relating bulk lifetime and Surface Recombination Velocity to effective lifetime measured under flash lamp illumination
Solar Energy Materials and Solar Cells, 2003Co-Authors: Jed Brody, A Rohatgi, Alan RistowAbstract:Abstract Photoconductance measurements are frequently used to determine the minority-carrier effective lifetime ( τ eff ), from which the bulk lifetime ( τ b ) and Surface Recombination Velocity ( S ) must be extracted. The exact solution to the continuity equation is used to determine the conditions of validity for three approximate equations relating τ eff to τ b and S : the steady-state approximation, the transient approximation, and the widely used simple equation (1/ τ eff =1/ τ b +2 S / W ). We show that only the steady-state approximation matches the exact solution over the entire range of τ eff , when the lamp time constant is 2.3 ms. When τ eff >20 μs , all the equations give approximately the same result. However, when τ eff
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analytical approximation of effective Surface Recombination Velocity of dielectric passivated p type silicon
Solid-state Electronics, 2001Co-Authors: Jed Brody, A RohatgiAbstract:Abstract New analytical equations are derived to approximate the effective Surface Recombination Velocity ( S eff ) on p-type silicon for three different cases: low-level injection (LLI) with Surface hole concentration ( p s ) much greater than Surface electron concentration ( n s ) and with silicon charge ( Q Si ) due primarily to ionized acceptors, LLI with n s ≫ p s and Q Si due primarily to ionized acceptors, and high-level injection with n s ≫ p s and Q Si due primarily to mobile electrons. The three new equations predict the dependence of S eff on individual parameters such as injection level ( Δn ), doping level ( N A ), and fixed dielectric charge ( Q f ). The new equations complement a previously derived result (for LLI with n s ≫ p s and Q Si due primarily to mobile electrons) and together allow reasonable explanations to be given for all sections of all S eff vs. Δn and S eff vs. N A curves generated by a quasi-exact numerical method. The analytical approximations are compared with the full numerical solutions. Under appropriate conditions, the analytical approximations agree with the numerical solutions within a factor of 3. Guided by the analytical approximations, numerical solutions are fitted to two sets of experimental data: the injection level dependence of S eff for an oxide-passivated wafer; and the doping dependence of S eff for wafers passivated by plasma-enhanced chemical vapor deposited nitride (SiN x ), conventional furnace oxide (CFO), and the SiN x /CFO stack. The SiN x /CFO stack not only provides Surface passivation that is superior to either dielectric alone; it is also less doping dependent. The analytical approximations indicate that this suppressed doping dependence could be due to a lower interface state density or a higher fixed dielectric charge ( Q f ).
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modeling and characterization of interface state parameters and Surface Recombination Velocity at plasma enhanced chemical vapor deposited sio2 si interface
Journal of Applied Physics, 1994Co-Authors: K Yasutake, S K Pang, Z Chen, A RohatgiAbstract:The effective Surface Recombination Velocity (Seff) at plasma enhanced chemical vapor deposited (PECVD) SiO2/Si interface as a function of Surface band bending under illumination was obtained by combining the photoconductive voltage decay measurements with indium tin oxide gate bias voltage, metal‐oxide‐semiconductor‐capacitance voltage, measurements and theoretical calculations. The capture cross sections for electrons and holes are obtained for the first time for the PECVD SiO2/Si interface state. Theoretical calculations of Seff based on the interface parameters, including interface state density and cross sections for electron and hole, were performed to see the effects of the positive oxide charge density (Qox) on Seff. It is found that roughly a 10 times larger value of Qox compared to the midgap interface state density is required to reduce Seff below 10 cm/s for 5 Ω cm (100) p‐type Si. These results prove the potential of PECVD SiO2 for effective passivation of Si Surfaces for devices like solar c...
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plasma enhanced chemical vapor deposited oxide for low Surface Recombination Velocity and high effective lifetime in silicon
Journal of Applied Physics, 1993Co-Authors: Z Chen, S K Pang, K Yasutake, A RohatgiAbstract:It is shown that plasma‐enhanced chemical‐vapor deposition (PECVD) of thin SiO2 on Si wafers followed by rapid thermal annealing (RTA) can result in very high effective carrier lifetime (≳5 ms) and extremely low Surface Recombination Velocity (≤2 cm/s). Thin SiO2 (∼100 A) layers were prepared by direct PECVD at 250 °C and RTA was performed at 350 °C in forming gas. Detailed metal‐oxide‐semiconductor analysis and model calculations showed that such a low Recombination Velocity is the result of moderately high positive oxide charge (5×1011–1×1012 cm−2 ) and relatively low midgap interface‐state density (5×1010–1×1011 cm−2 eV−1). RTA was found to be superior to furnace annealing, and a forming gas ambient was better than a nitrogen ambient for achieving a very low Surface Recombination Velocity. Some degradation in the Surface Recombination Velocity or effective lifetime was observed. It is found that a PECVD SiN cap on top of the thin SiO2 not only suppressed this degradation but also enhanced the effective...
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plasma enhanced chemical vapor deposited oxide for low Surface Recombination Velocity and high effective lifetime in silicon
Journal of Applied Physics, 1993Co-Authors: Z Chen, S K Pang, K Yasutake, A RohatgiAbstract:It is shown that plasma‐enhanced chemical‐vapor deposition (PECVD) of thin SiO2 on Si wafers followed by rapid thermal annealing (RTA) can result in very high effective carrier lifetime (≳5 ms) and extremely low Surface Recombination Velocity (≤2 cm/s). Thin SiO2 (∼100 A) layers were prepared by direct PECVD at 250 °C and RTA was performed at 350 °C in forming gas. Detailed metal‐oxide‐semiconductor analysis and model calculations showed that such a low Recombination Velocity is the result of moderately high positive oxide charge (5×1011–1×1012 cm−2 ) and relatively low midgap interface‐state density (5×1010–1×1011 cm−2 eV−1). RTA was found to be superior to furnace annealing, and a forming gas ambient was better than a nitrogen ambient for achieving a very low Surface Recombination Velocity. Some degradation in the Surface Recombination Velocity or effective lifetime was observed. It is found that a PECVD SiN cap on top of the thin SiO2 not only suppressed this degradation but also enhanced the effective lifetime.
Z Chen - One of the best experts on this subject based on the ideXlab platform.
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modeling and characterization of interface state parameters and Surface Recombination Velocity at plasma enhanced chemical vapor deposited sio2 si interface
Journal of Applied Physics, 1994Co-Authors: K Yasutake, S K Pang, Z Chen, A RohatgiAbstract:The effective Surface Recombination Velocity (Seff) at plasma enhanced chemical vapor deposited (PECVD) SiO2/Si interface as a function of Surface band bending under illumination was obtained by combining the photoconductive voltage decay measurements with indium tin oxide gate bias voltage, metal‐oxide‐semiconductor‐capacitance voltage, measurements and theoretical calculations. The capture cross sections for electrons and holes are obtained for the first time for the PECVD SiO2/Si interface state. Theoretical calculations of Seff based on the interface parameters, including interface state density and cross sections for electron and hole, were performed to see the effects of the positive oxide charge density (Qox) on Seff. It is found that roughly a 10 times larger value of Qox compared to the midgap interface state density is required to reduce Seff below 10 cm/s for 5 Ω cm (100) p‐type Si. These results prove the potential of PECVD SiO2 for effective passivation of Si Surfaces for devices like solar c...
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plasma enhanced chemical vapor deposited oxide for low Surface Recombination Velocity and high effective lifetime in silicon
Journal of Applied Physics, 1993Co-Authors: Z Chen, S K Pang, K Yasutake, A RohatgiAbstract:It is shown that plasma‐enhanced chemical‐vapor deposition (PECVD) of thin SiO2 on Si wafers followed by rapid thermal annealing (RTA) can result in very high effective carrier lifetime (≳5 ms) and extremely low Surface Recombination Velocity (≤2 cm/s). Thin SiO2 (∼100 A) layers were prepared by direct PECVD at 250 °C and RTA was performed at 350 °C in forming gas. Detailed metal‐oxide‐semiconductor analysis and model calculations showed that such a low Recombination Velocity is the result of moderately high positive oxide charge (5×1011–1×1012 cm−2 ) and relatively low midgap interface‐state density (5×1010–1×1011 cm−2 eV−1). RTA was found to be superior to furnace annealing, and a forming gas ambient was better than a nitrogen ambient for achieving a very low Surface Recombination Velocity. Some degradation in the Surface Recombination Velocity or effective lifetime was observed. It is found that a PECVD SiN cap on top of the thin SiO2 not only suppressed this degradation but also enhanced the effective...
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plasma enhanced chemical vapor deposited oxide for low Surface Recombination Velocity and high effective lifetime in silicon
Journal of Applied Physics, 1993Co-Authors: Z Chen, S K Pang, K Yasutake, A RohatgiAbstract:It is shown that plasma‐enhanced chemical‐vapor deposition (PECVD) of thin SiO2 on Si wafers followed by rapid thermal annealing (RTA) can result in very high effective carrier lifetime (≳5 ms) and extremely low Surface Recombination Velocity (≤2 cm/s). Thin SiO2 (∼100 A) layers were prepared by direct PECVD at 250 °C and RTA was performed at 350 °C in forming gas. Detailed metal‐oxide‐semiconductor analysis and model calculations showed that such a low Recombination Velocity is the result of moderately high positive oxide charge (5×1011–1×1012 cm−2 ) and relatively low midgap interface‐state density (5×1010–1×1011 cm−2 eV−1). RTA was found to be superior to furnace annealing, and a forming gas ambient was better than a nitrogen ambient for achieving a very low Surface Recombination Velocity. Some degradation in the Surface Recombination Velocity or effective lifetime was observed. It is found that a PECVD SiN cap on top of the thin SiO2 not only suppressed this degradation but also enhanced the effective lifetime.
K Yasutake - One of the best experts on this subject based on the ideXlab platform.
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modeling and characterization of interface state parameters and Surface Recombination Velocity at plasma enhanced chemical vapor deposited sio2 si interface
Journal of Applied Physics, 1994Co-Authors: K Yasutake, S K Pang, Z Chen, A RohatgiAbstract:The effective Surface Recombination Velocity (Seff) at plasma enhanced chemical vapor deposited (PECVD) SiO2/Si interface as a function of Surface band bending under illumination was obtained by combining the photoconductive voltage decay measurements with indium tin oxide gate bias voltage, metal‐oxide‐semiconductor‐capacitance voltage, measurements and theoretical calculations. The capture cross sections for electrons and holes are obtained for the first time for the PECVD SiO2/Si interface state. Theoretical calculations of Seff based on the interface parameters, including interface state density and cross sections for electron and hole, were performed to see the effects of the positive oxide charge density (Qox) on Seff. It is found that roughly a 10 times larger value of Qox compared to the midgap interface state density is required to reduce Seff below 10 cm/s for 5 Ω cm (100) p‐type Si. These results prove the potential of PECVD SiO2 for effective passivation of Si Surfaces for devices like solar c...
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plasma enhanced chemical vapor deposited oxide for low Surface Recombination Velocity and high effective lifetime in silicon
Journal of Applied Physics, 1993Co-Authors: Z Chen, S K Pang, K Yasutake, A RohatgiAbstract:It is shown that plasma‐enhanced chemical‐vapor deposition (PECVD) of thin SiO2 on Si wafers followed by rapid thermal annealing (RTA) can result in very high effective carrier lifetime (≳5 ms) and extremely low Surface Recombination Velocity (≤2 cm/s). Thin SiO2 (∼100 A) layers were prepared by direct PECVD at 250 °C and RTA was performed at 350 °C in forming gas. Detailed metal‐oxide‐semiconductor analysis and model calculations showed that such a low Recombination Velocity is the result of moderately high positive oxide charge (5×1011–1×1012 cm−2 ) and relatively low midgap interface‐state density (5×1010–1×1011 cm−2 eV−1). RTA was found to be superior to furnace annealing, and a forming gas ambient was better than a nitrogen ambient for achieving a very low Surface Recombination Velocity. Some degradation in the Surface Recombination Velocity or effective lifetime was observed. It is found that a PECVD SiN cap on top of the thin SiO2 not only suppressed this degradation but also enhanced the effective...
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plasma enhanced chemical vapor deposited oxide for low Surface Recombination Velocity and high effective lifetime in silicon
Journal of Applied Physics, 1993Co-Authors: Z Chen, S K Pang, K Yasutake, A RohatgiAbstract:It is shown that plasma‐enhanced chemical‐vapor deposition (PECVD) of thin SiO2 on Si wafers followed by rapid thermal annealing (RTA) can result in very high effective carrier lifetime (≳5 ms) and extremely low Surface Recombination Velocity (≤2 cm/s). Thin SiO2 (∼100 A) layers were prepared by direct PECVD at 250 °C and RTA was performed at 350 °C in forming gas. Detailed metal‐oxide‐semiconductor analysis and model calculations showed that such a low Recombination Velocity is the result of moderately high positive oxide charge (5×1011–1×1012 cm−2 ) and relatively low midgap interface‐state density (5×1010–1×1011 cm−2 eV−1). RTA was found to be superior to furnace annealing, and a forming gas ambient was better than a nitrogen ambient for achieving a very low Surface Recombination Velocity. Some degradation in the Surface Recombination Velocity or effective lifetime was observed. It is found that a PECVD SiN cap on top of the thin SiO2 not only suppressed this degradation but also enhanced the effective lifetime.
S K Pang - One of the best experts on this subject based on the ideXlab platform.
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modeling and characterization of interface state parameters and Surface Recombination Velocity at plasma enhanced chemical vapor deposited sio2 si interface
Journal of Applied Physics, 1994Co-Authors: K Yasutake, S K Pang, Z Chen, A RohatgiAbstract:The effective Surface Recombination Velocity (Seff) at plasma enhanced chemical vapor deposited (PECVD) SiO2/Si interface as a function of Surface band bending under illumination was obtained by combining the photoconductive voltage decay measurements with indium tin oxide gate bias voltage, metal‐oxide‐semiconductor‐capacitance voltage, measurements and theoretical calculations. The capture cross sections for electrons and holes are obtained for the first time for the PECVD SiO2/Si interface state. Theoretical calculations of Seff based on the interface parameters, including interface state density and cross sections for electron and hole, were performed to see the effects of the positive oxide charge density (Qox) on Seff. It is found that roughly a 10 times larger value of Qox compared to the midgap interface state density is required to reduce Seff below 10 cm/s for 5 Ω cm (100) p‐type Si. These results prove the potential of PECVD SiO2 for effective passivation of Si Surfaces for devices like solar c...
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plasma enhanced chemical vapor deposited oxide for low Surface Recombination Velocity and high effective lifetime in silicon
Journal of Applied Physics, 1993Co-Authors: Z Chen, S K Pang, K Yasutake, A RohatgiAbstract:It is shown that plasma‐enhanced chemical‐vapor deposition (PECVD) of thin SiO2 on Si wafers followed by rapid thermal annealing (RTA) can result in very high effective carrier lifetime (≳5 ms) and extremely low Surface Recombination Velocity (≤2 cm/s). Thin SiO2 (∼100 A) layers were prepared by direct PECVD at 250 °C and RTA was performed at 350 °C in forming gas. Detailed metal‐oxide‐semiconductor analysis and model calculations showed that such a low Recombination Velocity is the result of moderately high positive oxide charge (5×1011–1×1012 cm−2 ) and relatively low midgap interface‐state density (5×1010–1×1011 cm−2 eV−1). RTA was found to be superior to furnace annealing, and a forming gas ambient was better than a nitrogen ambient for achieving a very low Surface Recombination Velocity. Some degradation in the Surface Recombination Velocity or effective lifetime was observed. It is found that a PECVD SiN cap on top of the thin SiO2 not only suppressed this degradation but also enhanced the effective...
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plasma enhanced chemical vapor deposited oxide for low Surface Recombination Velocity and high effective lifetime in silicon
Journal of Applied Physics, 1993Co-Authors: Z Chen, S K Pang, K Yasutake, A RohatgiAbstract:It is shown that plasma‐enhanced chemical‐vapor deposition (PECVD) of thin SiO2 on Si wafers followed by rapid thermal annealing (RTA) can result in very high effective carrier lifetime (≳5 ms) and extremely low Surface Recombination Velocity (≤2 cm/s). Thin SiO2 (∼100 A) layers were prepared by direct PECVD at 250 °C and RTA was performed at 350 °C in forming gas. Detailed metal‐oxide‐semiconductor analysis and model calculations showed that such a low Recombination Velocity is the result of moderately high positive oxide charge (5×1011–1×1012 cm−2 ) and relatively low midgap interface‐state density (5×1010–1×1011 cm−2 eV−1). RTA was found to be superior to furnace annealing, and a forming gas ambient was better than a nitrogen ambient for achieving a very low Surface Recombination Velocity. Some degradation in the Surface Recombination Velocity or effective lifetime was observed. It is found that a PECVD SiN cap on top of the thin SiO2 not only suppressed this degradation but also enhanced the effective lifetime.
Serge Luryi - One of the best experts on this subject based on the ideXlab platform.
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extremely low Surface Recombination Velocity in gainassb algaassb heterostructures
Applied Physics Letters, 2005Co-Authors: C A Wang, D A Shiau, D Donetsky, S Anikeev, G Belenky, Serge LuryiAbstract:Low Surface Recombination Velocity is critical to the performance of minority carrier devices. Minority carrier lifetime in double heterostructures (DHs) of 0.53-eV p-GaInAsSb confined with 1.0-eV p-AlGaAsSb, and grown lattice-matched to GaSb, was measured by time-resolved photoluminescence. The structures were designed to be dominated by the heterointerface while minimizing the contribution of photon recycling to minority carrier lifetime. Surface Recombination Velocity as low as 30cm∕s for DHs was achieved. This value is over an order of magnitude lower than that reported in previous studies.
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effect of growth interruption on Surface Recombination Velocity in gainassb algaassb heterostructures grown by organometallic vapor phase epitaxy
Journal of Crystal Growth, 2004Co-Authors: C A Wang, D A Shiau, D Donetsky, S Anikeev, G Belenky, Serge LuryiAbstract:Abstract The effects of growth interruption on interfacial quality of GaInAsSb/AlGaAsSb heterostructures grown by organometallic vapor-phase epitaxy are reported. In situ reflectance monitoring and ex situ characterization by high-resolution X-ray diffraction, 4 K photoluminescence (PL), and time-resolved PL indicate that GaInAsSb is extremely sensitive to growth interruption time as well as the ambient atmosphere during interruption. By optimizing the growth switching sequence, Surface Recombination Velocity as low as 30 cm/s was achieved for GaInAsSb/AlGaAsSb double heterostructures.
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effect of growth interruption on Surface Recombination Velocity in gainassb algaassb heterostructures grown by organometallic vapor phase epitaxy
Other Information: PBD: 29 Apr 2004, 2004Co-Authors: C A Wang, D A Shiau, D Donetsky, S Anikeev, G Belenky, Serge LuryiAbstract:The effects of growth interruption on the quality of GaInAsSb/AlGaAsSb heterostructures grown by organometallic vapor phase epitaxy are reported. In-situ reflectance monitoring and ex-situ characterization by high-resolution x-ray diffraction, 4K photoluminescence (PL), and time-resolved PL indicate that GaInAsSb is extremely sensitive to growth interruption time as well as the ambient atmosphere during interruption. By optimizing the interruption sequence, Surface Recombination Velocity as low as 20 cm/s was achieved for GaInAsSb/AlGaAsSb double heterostructures.