In this paper, the authors have investigated the structural and electrical properties of thin film of Al2O3 deposited by radio-frequency sputtering and plasma enhanced atomic layer deposition (PEALD) technique. Different deposition and process parameters for the sputtered and PEALD Al2O3 films were chosen to investigate their effect on the structural and electrical characteristics of the film. X-ray diffraction result shows the dominant peak of Al2O3 in both the cases at 2θ = 56° indicating (312) film orientation. Multiple angle analysis of sputtered and PEALD Al2O3 film shows a refractive index in the range of 1.70–1.74 and 1.65–1.69, respectively. Electrical characteristics indicate that the device fabricated by PEALD and annealed at 425 °C shows the positive flatband voltage of 3.5 V and improved leakage behavior as compared to the film deposited by sputtering.

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In this article, we report the structural and electrical properties of metal-ferroelectric-high k dielectric-silicon (MFeIS) gate stack for non-volatile memory applications. Thin film of sputtered SrBi 2 Nb 2 O 9 (SBN) was used as ferroelectric material on 5-15 nm thick high-k dielectric (Al 2 O 3 ) buffer layer deposited using plasma-enhanced atomic layer deposition (PEALD). The effect of annealing on structural and electrical properties of SBN and Al 2 O 3 films was investigated in the temperature range of 350-1000 • C. X-ray diffraction results of the SBN and Al 2 O 3 show multiple phase changes with an increase in the annealing temperature. Multiple angle ellipsometry data show the change in the refractive index (n) of SBN film from 2.0941 to 2.1804 for non-annealed to samples annealed at 600 • C. For Al 2 O 3 film, n < 1.7 in the case of PEALD and n > 1.7 for sputtered film was observed. The leakage current density in MFeIS structure was observed to two orders of magnitude lower than metal/ferroelectric/silicon (MFeS) structures. Capacitance-voltage (C-V) characteristics for the voltage sweep of −10 to 10 V in dual mode show the maximum memory window of 1.977 V in MFeS structure, 2.88 V with sputtered Al 2 O 3 and 2.957 V with PEALD Al 2 O 3 in the MFeIS structures at the annealing temperature of 500 • C.

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We report the simulation of high-efficiency c-silicon Passivated Emitter Rear Contact (PERC) type solar cell structure with rear side passivated with HfO2 as a passivating material. Variation in the half length of pyramid has been carried out to investigate its effect on the solar cell electrical characteristics such as fill factor (FF), open circuit voltage (Voc) and efficiency. Aluminum back Surface Field (Al-BSF) and PERC type solar cell with Al2O3 passivation layer structures were also modeled for comparison. Effect of variation in passivation layer (HfO2) thickness (10 and 15 nm) and permittivity (k = 14 and 25) on the solar cell electrical characteristics has been investigated. Result shows the efficiency improvement in the PERC solar cell with HfO2 passivation layer by 0.5941% and 0.983% as compared to the Al-BSF and PERC with Al2O3 passivation layer at 8 μm pyramid half length. Increased series resistance and reduced FF has been observed with the incorporation of passivation layer at the solar cell structure. Negligible effect of passivation layer thickness has been observed on the solar cell electrical parameters whereas the permittivity value does have significant effect.