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Arnost Neugroschel

Bio: Arnost Neugroschel is an academic researcher from University of Florida. The author has contributed to research in topics: Bipolar junction transistor & Common emitter. The author has an hindex of 26, co-authored 94 publications receiving 2035 citations.


Papers
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TL;DR: In this paper, a direct-current currentvoltage measurement technique of interface and oxide traps on oxidized silicon is demonstrated using the gate-controlled parasitic bipolar junction transistor of a metaloxide-silicon field effect transistor in a p/n junction isolation well.
Abstract: A direct-current current-voltage (DCIV) measurement technique of interface and oxide traps on oxidized silicon is demonstrated It uses the gate-controlled parasitic bipolar junction transistor of a metal-oxide-silicon field-effect transistor in a p/n junction isolation well to monitor the change of the oxide and interface trap density The dc base and collector currents are the monitors, hence, this technique is more sensitive and reliable than the traditional ac methods for determination of fundamental kinetic rates and transistor degradation mechanisms, such as charge pumping >

182 citations

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TL;DR: In this article, the authors explore both qualitatively and quantitatively the mechanism of the improved current gain in bipolar transistors with polysilicon emitter contacts and make estimates about upper bounds on transport parameters in the principal regions of the devices.
Abstract: This paper presents the results of an experimental study designed to explore both qualitatively and quantitatively the mechanism of the improved current gain in bipolar transistors with polysilicon emitter contacts. Polysilicon contacts were deposited and heat treated at different conditions. The electrical properties Were measured using p-n junction test structures that are much more sensitive to the contact properties than are bipolar transistors. A simple phenomenological model was used to correlate, the structural properties with electrical measurements. Possible transport mechanisms are examined and estimates are made about upper bounds on transport parameters in the principal regions of the devices. The main conclusion of this study is that the minority-carrier transport in the polycrystalline silicon is dominated by a highly disordered layer at the polysilicon-monosilicon interface characterized by very low minority-carrier mobility. The effective recombination velocity at the n+polysilicon-n+monosilicon interface was found to be a strong function of fabrication conditions. The results indicate that the recombination velocity can be much smaller than 104cm/s.

82 citations

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TL;DR: In this article, the authors derived expressions for the position dependence of the excess minority-carrier density and for relevant recombination currents for quasi-neutral regions of semiconductor devices with position-dependent composition.
Abstract: For quasi-neutral regions of semiconductor devices with position-dependent composition, we have derived expressions for the position dependence of the excess minority-carrier density and for relevant recombination currents To make the development concrete, we study nonuniformly and heavily doped emitter regions of silicon p-n junction devices The expressions developed differ from those previously advanced in that they are in the form of a multiple integral series, yielding, by truncation, many different orders of approximation Correspondences exist between some of the different orders of approximation and various solutions previously obtained All of the mechanisms relating to hole and electron transport in position-dependent heavily doped semiconductors are accounted for in the new expressions These mechanisms include bandgap narrowing, majority-carrier degeneracy, Auger recombination lifetime, etc To assess the accuracy of the various orders of approximation, we compare their predictions with a numerical solution We determine that the simplest approximation, which contains only one term of the integral series, is accurate to within about 5 percent of the numerical solution for thin emitters (∼02 µm) provided the surface recombination velocity is less than 105cm/s It thus applies directly to bipolar transistors with polysilicon contacts, and to surface-passivated solar cells This new solution, which we call the zeroth-order or quasi-neutral quasi-equilibrium approximation, is simpler than solutions previously put forward If the emitter junction is deep or the contact is ohmic, the higher-order approximations provide whatever accuracy is needed We separate the emitter recombination current into charge and a characteristic time, enabling the calculation of the contribution of emitter to capacitance and to delay in the time domain or phase shift in the frequency domain

75 citations

Journal ArticleDOI
TL;DR: The polysilicon-back solar cells as discussed by the authors showed improvements in red spectral response (RSR) and open-circuit voltage, and a decrease in effective surface recombination velocity S is responsible for this improvement.
Abstract: We report the first use of a (silicon)/(heavily doped polysilicon)/(metal) structure to replace the conventional high-low junction or back-surface-field (BSF) structure, of silicon solar cells. Compared with BSF and back-ohmic-contact (BOC) control slimples, the polysilicon-back solar cells, show improvements in red spectral response (RSR) and open-circuit voltage. Measurement reveals that a decrease in effective surface recombination velocity S is responsible for this improvement. Decreased S results for n-type (Si:As) polysilicon, consistent with past findings for bipolar transistors, and for p-type (Si:B) polysilicon, reported here for the first time. Though the present polysilicon-back solar cells are far from optimal, the results suggest a new class of designs for high efficiency silicon solar cells. Detailed technical reasons are advanced to support this view.

67 citations

Journal ArticleDOI
TL;DR: In this article, the degradation of the common-emitter forward current gain h/sub FE/ of submicron silicon npn bipolar transistors at low reverse emitter-base junction applied voltage is caused by primary hot holes of the n/sup +//p emitter tunneling current rather than secondary hot electrons generated by the hot holes or thermally generated hot electrons.
Abstract: Experimental evidences are given which demonstrate that degradation of the common-emitter forward current gain h/sub FE/ of submicron silicon npn bipolar transistors at low reverse emitter-base junction applied voltage is caused by primary hot holes of the n/sup +//p emitter tunneling current rather than secondary hot electrons generated by the hot holes or thermally-generated hot electrons. Experiments also showed similar kinetic energy dependence of the generation rate of oxide/silicon interface traps by primary hot electrons and primary hot holes. Significant h/sub FE/ degradation was observed at stress voltages less than 2.4 V.

65 citations


Cited by
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TL;DR: A local mobility function, set up in terms of a simple Mattiessen's rule, provides a careful description of MOSFET operation in a wide range of normal (or gate) electric fields.
Abstract: A semiempirical model for carrier mobility in silicon inversion layers is presented. The model, strongly oriented to CAD (computer-aided design) applications, is suitable for two-dimensional numerical simulations of nonplanar devices. A local mobility function, set up in terms of a simple Mattiessen's rule, provides a careful description of MOSFET operation in a wide range of normal (or gate) electric fields, channel impurity concentrations of between 5*10/sup 14/ cm/sup -3/ and 10/sup 17/ cm/sup -3/ for the acceptor density of states and 6*10/sup 14/ cm/sup -3/ and 3*10/sup 17/ cm/sup -3/ for the donor density of states; and temperatures between 200 K and 460 K. Best-fit model parameters are extracted by comparing the calculated drain conductance with a very large set of experimental data points. >

697 citations

Journal ArticleDOI
TL;DR: In this paper, a passivated rear contact is used to replace point contact passivation schemes for high-efficiency n-type crystalline silicon solar cells, which is based on an ultra-thin tunnel oxide (SiO2) and a phosphorus-doped silicon layer.

556 citations

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TL;DR: The silicon-germanium heterojunction bipolar transistor (SiGe HBT) as mentioned in this paper is the first practical bandgap-engineered device to be realized in silicon and has achieved state-of-the-art performance.
Abstract: The silicon-germanium heterojunction bipolar transistor (SiGe HBT) is the first practical bandgap-engineered device to be realized in silicon. SiGe HBT technology combines transistor performance competitive with III-V technologies with the processing maturity, integration levels, yield, and hence, cost commonly associated with conventional Si fabrication. In the ten-and-one-half years since the first demonstration of a functional transistor, SiGe HBT technology has emerged from the research laboratory, entered manufacturing on 200-mm wafers, and is poised to enter the commercial RF and microwave market. State-of-the-art SiGe HBT's can deliver: (1) f/sub T/ in excess of 50 GHz; (2) f/sub max/ in excess of 70 GHz; (3) minimum noise figure below 0.7 dB at 2.0 GHz; (4) 1/f noise corner frequencies below 500 Hz; (5) cryogenic operation; (6) excellent radiation hardness; (7) competitive power amplifiers; and (8) reliability comparable to Si. A host of record-setting digital, analog, RF, and microwave circuits have been demonstrated in the past several years using SiGe HBT's, and recent work on passives and transmission lines on Si suggest a migratory path to Si-based monolithic microwave integrated circuits (MMIC's) is possible. The combination of SiGe HBT's with advanced Si CMOS to form an SiGe BiCMOS technology represents a unique opportunity for Si-based RF system-on-a-chip solutions. This paper reviews state-of-the-art SiGe HBT technology and assesses its potential for current and future RF and microwave systems.

479 citations

Journal ArticleDOI
TL;DR: In this article, a parameterization for band-to-band Auger recombination in silicon at 300 K was proposed, which accurately fits the available experimental lifetime data for arbitrary injection level and arbitrary dopant density, for both n-type and p-type dopants.
Abstract: A parameterization for band-to-band Auger recombination in silicon at 300 K is proposed. This general parameterization accurately fits the available experimental lifetime data for arbitrary injection level and arbitrary dopant density, for both n-type and p-type dopants. We confirm that Auger recombination is enhanced above the traditional free-particle rate at both low injection and high injection conditions. Further, the rate of enhancement is shown to be less for highly injected intrinsic silicon than for lowly injected doped silicon, consistent with the theory of Coulomb-enhanced Auger recombination. Variations on the parameterization are discussed.

470 citations

Journal ArticleDOI
D.B.M. Klaassen1
TL;DR: In this paper, the authors presented a physics-based analytical model that unifies the descriptions of majority and minority carrier mobility and that includes screening of the impurities by charge carriers, electron-hole scattering and clustering of impurities.
Abstract: In Part I we presented the first physics-based analytical model that unifies the descriptions of majority and minority carrier mobility and that includes screening of the impurities by charge carriers, electron-hole scattering and clustering of impurities. Here the model is extended to include the full temperature dependence of both majority and minority carrier mobility. Based on our model and experimental data on the minority carrier diffusion length as a function of temperature, the temperature dependence of the carrier lifetime is determined. The model is especially suited for device simulation purposes, because the carrier mobility is given as an analytical function of the donor, acceptor, electron and hole concentrations and of the temperature.

442 citations