T.H. Glisson

Velocity‐field characteristics of GaAs with Γc6‐Lc6‐Xc6 conduction‐band ordering

This paper describes Monte Carlo calculations of velocity‐field characteristics for GaAs using the recent experimental conduction‐band ordering of Aspnes, which places the Lc6(111) conduction‐band minima lower in energy than the Xc6(100) minima. These calculations use intervalley deformation potentials which give the best fit to recent high‐field drift velocity measurements, and at the same time give good agreement with accepted peak velocity and threshold field values.This paper describes Monte Carlo calculations of velocity‐field characteristics for GaAs using the recent experimental conduction‐band ordering of Aspnes, which places the Lc6(111) conduction‐band minima lower in energy than the Xc6(100) minima. These calculations use intervalley deformation potentials which give the best fit to recent high‐field drift velocity measurements, and at the same time give good agreement with accepted peak velocity and threshold field values.

Alloy scattering and high field transport in ternary and quaternary III–V semiconductors☆

Abstract A technique is described for the estimation of the influence of random potential alloy scattering on the high field transport properties of quaternary III–V semiconductors obtained by Monte Carlo simulation. The approach is based on an extension of a theoretical model for scattering in the ternary alloys. The magnitude of the scattering potential is an important parameter in alloy scattering, and three proposed models for calculating this potential are discussed. These are the energy bandgap difference, the electron affinity difference, and the heteropolar energy difference for the appropriate binary compounds. The technique is used in the Monte Carlo method to study the influence of alloy scattering on the transport properties of III–V quaternary alloys. The results of this study are used in a device model to estimate device parameters for FETs.

Energy bandgap and lattice constant contours of iii–v quaternary alloys

Energy band gap and lattice constant contours are presented for the nine quaternary alloys formed from Al, Ga, In and P, As, Sb. The quaternary bandgaps were obtained using an interpolation formula proposed by Moonet al. The quater nary lattice constants were obtained by use of a linear interpolation technique using the binary lattice constants as boundary values.

Velocity‐field characteristics of Ga1−xInxP1−yAsy quaternary alloys

The electron drift‐velocity–electric‐field relationship has been calculated for the Ga1−xInxP1−yAsy quaternary alloy using the Monte Carlo method. Emphasis has been placed on the compositional range for which the alloy is lattice matched to GaAs and InP. These calculations suggest that this quaternary offers promise as a material for microwave semiconductor devices, including field‐effect transistors and transferred electron devices.The electron drift‐velocity–electric‐field relationship has been calculated for the Ga1−xInxP1−yAsy quaternary alloy using the Monte Carlo method. Emphasis has been placed on the compositional range for which the alloy is lattice matched to GaAs and InP. These calculations suggest that this quaternary offers promise as a material for microwave semiconductor devices, including field‐effect transistors and transferred electron devices.

Monte Carlo calculation of the velocity‐field relationship for gallium nitride

The Monte Carlo technique has been used to calculate the velocity‐field relationship for GaN. The calculation has included polar optical scattering, acoustic scattering, piezoelectric scattering, and ionized impurity scattering. The electron mobility has also been evaluated at low fields as a function of impurity concentration.

Energy bandgap and lattice constant contours of iii-v quaternary alloys of the form Ax By Cz D or ABx Cy Dz

Energy bandgap and lattice constant contours are presented for the six quaternary alloys formed from Al, Ga, In and P, As, Sb, with compositions of the form Ax By C(1−y). D or ABx Cy D1−x−y . The quaternary bandgaps and lattice constants were obtained using an interpolation formula proposed by the present authors.

Velocity‐field relationship of InAs‐InP alloys including the effects of alloy scattering

The drift velocity–electric field relationship for the ternary alloy InAs1−xPx has been studied by the Monte Carlo methd. Random potential alloy scattering has been included in the calculations, along with polar optical scattering, intervalley scattering, acoustic scattering, piezoelectric scattering, and ionized impurity scattering. The low‐field electron mobility has also been calculated throughout the compositional range for the alloy.

Monte Carlo simulation of real‐space electron transfer in GaAs‐AlGaAs heterostructures

The Monte Carlo method has been used to simulate electron transport in GaAs/AlGaAs heterostructures with an electric field applied parallel to the heterojunction interface. The simulations indicate that a unique physical mechanism for negative differential conductivity is provided by such layered heterostructures, which is analogous in many respects to the Gunn effect. This mechanism has been termed ’’real‐space electron transfer’’ since it involves the transfer of electrons from a high‐mobility GaAs region to an adjacent low‐mobility AlGaAs region as the applied electric field intensity is increased. The simulations further indicate that the important details of the resulting velocity‐field characteristics for these layered heterostructures can be controlled primarily through material doping densities, layer thicknesses, and the material properties of the individual layers. Thus, the phenomenon of real‐space electron transfer potentially provides the ability to ’’engineer’’ those basic material propertie...

Negative resistance and peak velocity in the central (000) valley of III–V semiconductors☆

Abstract The negative resistance in III–V materials such as GaAs at large electric fields is generally recognized as arising from the transfer of electrons from the central (000) valley to higher lying minima in the conduction band. Monte Carlo transport studies show that the negative resistance effect is still present in III–V materials when the valley spacing is increased to large values (> 0.5 eV) and even present when the higher minima are eliminated entirely from the calculations. This negative resistance arises from basic transport properties of the central valley. Studies are presented of the basic negative resistance effect in the central valley of III–V materials as well as studies of Al1−xInxAs (x ∼ 0.75) and Ga1−xInxAs (x ∼ 0.6) which are two specific materials where the negative resistance effect is due predominantly to the central valley.

Transient transport in central-valley-dominated ternary III–V alloys

Abstract This paper describes results of an ensemble Monte Carlo study of ballistic transport and velocity overshoot in Al 0.25 In 0.75 As and Ga 0.4 In 0.6 As. Velocity overshoot in these materials is limited primarily by transport properties of the central valley. The transfer of carriers into higher-lying energy valleys occurs only after velocity overshoot has subsided. Instantaneous conduction-band occupancies, carrier positions, and carrier velocities are given as functions of time for electric field intensities of 10 and 40 kV/cm. These curves show that transient velocities exceed steady-state values by as much as 27 to one, that these transients persist over distances ranging from 0.22 to 0.79 μm, and that average velocities during velocity overshoot are as large as 5.6 × 10 7 cm/sec. These results have important implications for submicron-device applications of these materials.