共查询到20条相似文献,搜索用时 594 毫秒
1.
《Superlattices and Microstructures》1995,18(1):1-8
The forward delay time (τF) of heterojunction bipolar transistors (HBTs) is calculated using a hybrid model of carrier transport. A rigorous quantum-mechanical treatment of electron tunneling and thermionic emission across the spike at the emitter-base junction is used to determine the energy of the electron flux injected into the base region. This flux is used as an initial distribution in a regional Monte Carlo simulator to model electron transport from base to sub-collector. In this paper, we estimate the base transit time using the impulse response technique and the collector delay time using the expression of Laux and Lai (IEEE Electron Device Letters, 11, 174, 1990). Improvements to the hybrid model proposed here to reduce some of the discrepancies between measured and calculated values of ƒτ for some InAlAs/InGaAs and InP/InGaAs structures reported in the literature are discussed. 相似文献
2.
《Superlattices and Microstructures》1994,15(4):373-376
We report an investigation of ballistic electron transport in GaAs/AlGaAs p-i-n single barrier structures with magnetic fields of up to 14T applied parallel to the tunneling direction (B//z). The energy distribution and relaxation processes of the non-equilibrium electron population injected into the p-doped collector from the Landau levels of the emitter accumulation layer are studied by means of electroluminescence (EL) spectroscopy. The observation of emitter Landau level structure in the ballistic electron EL spectra shows that the 2D to 3D tunneling process is elastic. In addition to the ballistic electron EL, cross-barrier recombination between the electron and hole accumulation layers is observed. This allows a precise determination of the initial energy distribution of the injected electrons. 相似文献
3.
《Superlattices and Microstructures》1995,18(1):9-19
This paper describes a numerical approach to the modeling of PNP HBTs in the InP-based materials systems (InP/InGaAs and InAlAs/InGaAs). Initial device analysis was achieved in the drift-diffusion limit by self-consistent numerical solution of the Poisson, carrier continuity and conductor equations subject to the device's geometry and boundary conditions imposed by the device's biasing. Simulation results are compared with the available experimental results and good agreement is found. For the InP/InGaAs and InAlAs/InGaAs heterojunctions, the valence band discontinuities are larger than for the AlGaAs/GaAs system so grading of the emitter-base junction and tunneling effects are important. For completeness, nonclassical effects were also considered. For the emitter-base junctions, hole tunneling was considered, particularly at low forward bias. The inverse dependence of the hole tunneling on effective mass was found to lead to significantly more light hole than heavy hole tunneling in calculating the emitter injection current. In addition, since very narrow base regions (25-35 nm) can be employed while keeping the base spreading resistance low due to the electron's higher mobility, ballistic hole transport should also be considered. 相似文献
4.
《Superlattices and Microstructures》2001,30(2):111-117
In this work, an improved InGaP/GaAs heterostructure-emitter bipolar transistor (HEBT) with an InGaP wide-bandgap collector is investigated. In the emitter–base region, the thin narrow bandgap n-type GaAs layer is sandwiched between a wide-bandgap N-type InGaP confinement layer and a narrow-bandgap p-type GaAs base layer. In the collector–base structure, an undoped 30 Å-thick GaAs spacer and a heavily doped 30 Å-thick GaAs are inserted between the base and collector. Due to the absence of a potential spike both at the base–emitter and base–collector junctions, the studied device shows lower offset and saturation voltages. In addition, not only are the excellent current–voltage characteristics observed, but also the undesired effects, e.g. the electron blocking effect, are completely eliminated. 相似文献
5.
P. A. Tchertchian C. J. Wagner T. J. Houlahan
Jr. B. Li D. J. Sievers J. G. Eden 《等离子体物理论文集》2011,51(10):889-905
Coupling electron‐hole (e–‐ h+) and electron‐ion plasmas across a narrow potential barrier with a strong electric field provides an interface between the two plasma genres and a pathway to electronic and photonic device functionality. The magnitude of the electric field present in the sheath of a low temperature, nonequilibrium microplasma is sufficient to influence the band structure of a semiconductor region in immediate proximity to the solid‐gas phase interface. Optoelectronic devices demonstrated by leveraging this interaction are described here. A hybrid microplasma/semiconductor photodetector, having a Si cathode in the form of an inverted square pyramid encompassing a neon microplasma, exhibits a photosensitivity in the ~420–1100 nm region as high as 3.5 A/W. Direct tunneling of electrons into the collector and the Auger neutralization of ions arriving at the Si surface appear to be facilitated by an n ‐type inversion layer at the cathode surface resulting from bandbending by the microplasma sheath electric field. Recently, an npn plasma bipolar junction transistor (PBJT), in which a low temperature plasma serves as the collector in an otherwise Si device, has also been demonstrated. Having a measured small signal current gain hfe as large as 10, this phototransistor is capable of modulat‐ing and extinguishing the collector plasma with emitter‐base bias voltages <1 V. Electrons injected into the base when the emitter‐base junction is forward‐biased serve primarily to replace conduction band electrons lost to the collector plasma by secondary emission and ion‐enhanced field emission in which ions arriving at the base‐collector junction deform the electrostatic potential near the base surface, narrowing the potential barrier and thereby facilitating the tunneling of electrons into the collector. Of greatest significance, therefore, are the implications of active, plasma/solid state interfaces as a new frontier for plasma science. Specifically, the PBJT provides the first opportunity to control the electronic properties of a material at the boundary of, and interacting with, a plasma. By specifying the relative number densities of free (conduction band) and bound (valence band) electrons at the base‐collector interface, the PBJT's emitter‐base junction is able to dictate the rates of secondary electron emission (including Auger neutralization) at the semiconductor‐plasma interface, thereby offering the ability to vary at will the effective secondary electron emission coefficient for the base surface (© 2011 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim) 相似文献
6.
《Superlattices and Microstructures》2003,33(4):209-216
We report on new InGaP/AlGaAs/GaAs composite emitter heterojunction bipolar and phototransistors (CEHBTs/CEHPTs) with a low turn-on voltage. The composite emitter comprised of the digital graded superlattice emitter and the InGaP sub-emitter is used to smooth out potential spike associated with the emitter–base heterojunction and to obtain a low emitter–base turn-on voltage. A fabricated CEHBT exhibits a small offset voltage of 55 mV and a low turn-on voltage of 0.83 V with a dc current gain as high as 150. In case of a CEHPT’s collector–emitter characteristics with base floating, optical gains increase with increasing input optical power. Furthermore, the collector current saturation voltage is small due to a low turn-on voltage. We obtain an optical gain larger than 6.83 with a collector current saturation voltage smaller than 0.5 V. On the other hand, performance results of a CEHPT with two- and three-terminal configuration were investigated and compared. 相似文献
7.
High-Speed InGaAs/InP Double Heterostructure Bipolar Transistor with High Breakdown Voltage 总被引:3,自引:0,他引:3
下载免费PDF全文
![点击此处可从《中国物理快报》网站下载免费的PDF全文](/ch/ext_images/free.gif)
e design and fabricate an InGaAs/InP double heterostructure bipolar transistor (DHBT). The spike of the conduction band discontinuity between InGaAs base and InP collector is successfully eliminated by insertion of an InGaAs layer and two InGaAsP layers. The current gain cutoff frequency and maximum oscillation frequency are as high as 155 and 144GHz. The breakdown voltage in common-emitter configuration is more than 7V. The high cutoff frequency and high breakdown voltage make high-speed andhigh-power circuits possible 相似文献
8.
《Superlattices and Microstructures》1995,17(3):253
An electron self-energy effect on a graded-gap heterojunction bipolar transistor at T=0 is considered. It is found that two competing mechanisms affect the collector current vs. emitter base bias voltage relations: (I) threshold voltage lowering for electron injection from emitter to base improves it: while (II) a decelerating field on injected minority carriers in the base degrades it. In a sufficiently large built-in field in the graded-gap base, negative transconductance appears as a result of the effect (I). 相似文献
9.
10.
We present a combined scanning tunneling microscopy and ballistic electron emission microscopy study of electron transport across an epitaxial Pb/Si(111) interface. Experiments with a self-assembled Pb nanoscale wedge reveal the phenomenon of confinement-enhanced interfacial transport: a proportional increase of the electron injection rate into the semiconductor with the frequency of electron oscillations in the Pb quantum well. 相似文献
11.
A “capacitor” model of the hysteresis is developed using the self-consistent calculation of the tunneling current in a w-GaN/AlGaN(0001) double-barrier structure. In the framework of this model, the current jumps and changes in the potential
and the electric field in the structure upon transition from one branch of the current loop to the other branch are considered
a result of the recharging of two joined capacitors with the plates located at the positions of the extrema of variations
in the electron density in the regions of the emitter, the quantum well, and the collector. It is demonstrated that, when
the external and internal fields in the quantum well compensate for each other, the tunneling current is sharply and irreducibly
switched to the characteristics of the other resonance and forms a wide hysteresis loop so that, in the branches of this loop,
the charge is redistributed between the quantum well and the collector. If the fields coincide with each other, there arises
a narrow “singleresonance” hysteresis loop, which is accompanied by the transfer of the electron charge from the emitter to
the collector. The developed model leads to agreement with the results of the self-consistent calculations and provides an
illustrative interpretation of the complex electron tunneling processes.
Original Russian Text ? A.N. Razzhuvalov, S.N. Grinyaev, 2009, published in Fizika Tverdogo Tela, 2009, Vol. 51, No. 1, pp.
168–177. 相似文献
12.
Nonmonotonic bias voltage dependence of the magnetocurrent in GaAs-based magnetic tunnel transistors
Magnetic tunnel transistors are used to study spin-dependent hot electron transport in thin CoFe films and across CoFe/GaAs interfaces. The magnetocurrent observed when the orientation of a CoFe base layer moment is reversed relative to that of a CoFe emitter, is found to exhibit a pronounced nonmonotonic variation with electron energy. A model based on spin-dependent inelastic scattering in the CoFe base layer and strong electron scattering at the CoFe/GaAs interface, resulting in a broad electron angular distribution, can well account for the variation of the magnetocurrent in magnetic tunnel transistors with GaAs(001) and GaAs(111) collectors. 相似文献
13.
High-Breakdown-Voltage Submicron InGaAs/InP Double Heterojunction Bipolar Transistor with ft=170GHz and fmax=253GHz
下载免费PDF全文
![点击此处可从《中国物理快报》网站下载免费的PDF全文](/ch/ext_images/free.gif)
The layer structure of InGaAs/InP double heterojunction bipolar transistor (DHBT) is designed to enhance the frequency performance and breakdown voltage. The composition-graded base structure is used to decrease the base transit time. The InGaAs setback layer and two highly doped InGaAsP layers are used to eliminate the conduction band spike of the collector. The submicron-emitter InGaAs/InP DHBT is fabricated successfully. The base contact resistance is greatly decreased by optimization of contact metals. The breakdown voltage is more than 6V. The current gain cutoff frequency is as high as 170GHz and the maximum oscillation frequency reached 253GHz. The DHBT with such high performances can be used to make W-band power amplifier. 相似文献
14.
《Superlattices and Microstructures》1988,4(6):697-700
A mathematical formalism for use in the study of the temperature dependence of Tsu-Esaki tunneling currents is developed. The discussion includes recently discovered corrections to the Tsu-Esaki tunneling current calculation. These corrections involve emitter and collector electron density effects. The tunneling current is fully amenable to numerical calculation, but some calculations can be facilitated by analytic techniques. An operator technique of Blankenbecler is illustrated and used to generate low temperature series expansions for the tunneling current and emitter-collector electron densities. 相似文献
15.
A mathematical formalism for use in the study of the temperature dependence of Tsu-Esaki tunneling currents is developed. The discussion includes recently discovered corrections to the Tsu-Esaki tunneling current calculation. These corrections involve emitter and collector electron density effects. The tunneling current is fully amenable to numerical calculation, but some calculations can be facilitated by analytic techniques. An operator technique of Blankenbecler is illustrated and used to generate low temperature series expansions for the tunneling current and emitter-collector electron densities. 相似文献
16.
V. M. Lobanov 《Technical Physics》2005,50(11):1485-1489
The height of an extra low-energy maximum in the energy distribution of electrons tunneling from crystalline carbon fibers
and carbon nanotubes is studied as a function of emitter heating and emitter rotation relative to the energy analyzer axis.
The relationships found are related to emission from electron states on the surface of the reconstructed nanocrystals and
nanotubes. 相似文献
17.
We demonstrate a mesoscopic spin polarizer/analyzer system that allows the spin polarization of current from a quantum point contact in a large in-plane magnetic field to be measured. A transverse electron focusing geometry is used to couple current from an emitter point contact into a collector point contact. At large in-plane fields, with the point contacts biased to transmit only a single spin (g70% are found for both emitter and collector at 300 mK and 7 T in-plane field. 相似文献
18.
Michelle S. Meruvia Ivo A. Hümmelgen Rosamaria W.C. Li Jonas Gruber 《Solid State Communications》2006,139(1):27-30
We report the development of a hybrid semiconductor-metal-semiconductor permeable-base transistor in vertical architecture. This transistor has a p-type silicon collector, a thin tin layer as base and a magnetoresistive conjugated polymer, poly(9,9-dioctyl-1,4-fluorenylenevinylene), as emitter material. The transistor transport characteristics are dependent on the applied magnetic field and the base transport factor for positive charge carriers is nearly ideal, independently of the magnetic field in the investigated range. 相似文献
19.
Yu. N. Khanin E. E. Vdovin L. Eaves A. Patane M. Henini 《Bulletin of the Russian Academy of Sciences: Physics》2007,71(8):1127-1129
Tunneling transport through a one-barrier GaAs/(AlGa)As/GaAs heterostructure containing self-assembled InAs quantum dots has been investigated at low temperatures. An anomalous increase in the tunneling current through quantum dots in magnetic fields oriented both parallel and perpendicular to the current is observed. This increase is a manifestation of the Fermi-edge singularity in the current as a result of the interaction of a tunneling electron with the electron gas in the emitter. 相似文献
20.
S. Oda S.Y. Huang M.A. Salem D. Hippo H. Mizuta 《Physica E: Low-dimensional Systems and Nanostructures》2007,38(1-2):59
Monodispersed silicon nanocrystals show novel electrical and optical characteristics of silicon quantum dots, such as single-electron tunneling, ballistic electron transport, visible photoluminescence and high-efficiency electron emission.Single-electron memory effects have been studied using a short-channel MOSFET incorporating Si quantum dots as a floating gate. Surface nitridation of Si nanocrystal memory nodes extends the charge-retention time significantly. Single-electron storage in individual Si dots has been evaluated by Kelvin probe force microscopy.Photoluminescence and electron emission are observed for surface-oxidized silicon nanocrystals. Efficiency of the no-phonon-assisted transition increases with decreasing core Si size. Electron emission efficiency as high as 5% has been achieved for the Si-nanocrystal-based cold electron emitter devices. The non-Maxwellian energy distribution of emitted electrons suggests that the mechanism of electron emission is due to ballistic transport through arrays of surface-oxidized Si nanocrystals. Combined with the ballistic electron emission, the quasi-direct light emission properties can be used for developing Si-based lasers. 相似文献