Equivalent series resistance

About: Equivalent series resistance is a research topic. Over the lifetime, 5335 publications have been published within this topic receiving 83362 citations. The topic is also known as: ESR.

Effects of gamma-ray irradiation on interface states and series-resistance characteristics of BiFeO3 MOS capacitors

Abstract: The effects of radiation on the electrical-interface-state density ( D it ) and series resistance ( R s ) characteristics of BiFeO 3 MOS capacitors were studied in this work. To study the response of MOS devices to gamma irradiation over a range of doses, MOS samples were irradiated using a Co-60 gamma-ray source from 0.5 to 16 grays at a dose rate of 0.0030 Gy/s. C – V and G / ω – V measurements were recorded prior to and after irradiation at high (1 MHz) frequency. The effects of the radiation were determined from analysis of the C – V and G / ω – V curves. A slightly decrease in the R s values with increasing irradiation dose was observed. The total interface-state density was found to decrease because of the reordering and restructuring of radiation-induced defects in the MOS capacitors. The experimental results indicate that the electrical R s and D it characteristics of BiFeO 3 MOS capacitors depend on the gamma-irradiation dose, and the calculated densities of the interface states are on the order of 10 11 eV −1 cm −2 . However, the calculated D it values are not high enough to pin the Fermi level of the Si substrate and thereby corrupt device operation over the given dose range.

Analysis of different forward current–voltage behaviours of Al implanted 4H-SiC vertical p–i–n diodes

Abstract: In this work different experimental current–voltage behaviours of several Al implanted 4H-SiC p–i–n diodes are investigated by means of numerical simulations in a wide range of currents and temperatures. Some devices for which recombination and tunneling are the dominant current processes at all biases are classified as “leaky” diodes. The well behaved diodes, instead, show good rectifying characteristics with a current conduction due to tunneling below 1.7 V, recombination between 1.7 V and 2.5 V, and diffusion processes above 2.5 V. At higher current regimes, a series resistance in excess of 1 mΩ cm 2 becomes the main current limiting factor. Depending on the relative weight between the contact resistances and the internal diode resistance, different temperature dependencies of the current are obtained. A good agreement between numerical and measured data is achieved employing temperature-dependent carrier lifetime and mobility as fitting parameters.

Current drive enhancement by using high-permittivity gate insulator in SOI MOSFET's and its limitation

Abstract: Speed enhancement effects by using a high-permittivity gate insulator in SOI MOSFETs and its limitation were investigated by a two-dimensional device simulator and circuit simulator. The SOI structure is suitable to have excellent current drive by using a high-permittivity gate insulator. Although the gate capacitance increases as a function of its dielectric constant, the current drive does not increase proportionally due to the inversion capacitance. According to the simulation results of the delay time, when the pulse waveforms driven by a CMOS inverter are propagated through 1 mm-long interconnects, the delay time significantly reduces at a dielectric constant value of around 25 (Ta/sub 2/O/sub 5/). Thus, it is worthwhile using Ta/sub 2/O/sub 5/ for gate insulator to achieve high-speed operation. Furthermore, the reduction of source parasitic series resistance is a key issue to realize the highest current drive by using a high-permittivity gate insulator in SOI MOSFET.

High-Performance Chirped Electrode Design for Cat's Eye Retro-Reflector Modulators

Abstract: Modulating retro-reflector (MRR) systems typically use large area surface-normal modulators with large lateral current flow. Frequency response is limited by the resistance capacitance time constant. In cat's eye MRRs, only a small percentage of the modulator area is illuminated at a time. Uniform resistance to each part of the modulator is desired to decrease location dependence of frequency response. A novel "chirped" grid electrode was designed to balance semiconductor sheet resistance and metal line resistance components of the series resistance. Measured rise/fall times across the device showed good uniformity

Loss Analysis of Monocrystalline CdTe Solar Cells With 20% Active-Area Efficiency

Abstract: We report a monocrystalline CdTe/MgCdTe double-heterostructure solar cell with an a-Si:H hole contact and an ITO/SiO x electrode stack. Similar designs have achieved high open-circuit voltages, but low short-circuit current densities and fill factors have limited the cell efficiencies. We investigate the origin of these losses, and, in addressing some of them, achieve a maximum total-area efficiency of 18.5% and active-area efficiency of 20.3% measured under AM1.5G illumination. Additional cells have been measured with open-circuit voltages of up to 1.11 V, while still maintaining respectable fill factors and no rollover. The lack of rollover, either before or after open circuit, confirms the potential of this approach to reach very high efficiencies. The optical losses within the device are quantified and analyzed across the spectrum to determine if there exists potential for increased current generation through a reduction in parasitic absorption. In addition, fitting the current–voltage characteristic reveals that the leading cause of the less-than-ideal fill factor is series resistance, which contributes a 7% absolute loss.