Fermi-level pinning phenomena due to DX centers in AlGaAs/GaAs HEMT’s are analyzed using two-dimensional numerical simulation based on a drift-diffusion model. A DX center model is introduced assuming Fermi-Dirac statistics for ionized donor density with the aluminum mole fraction dependence of the deep-donor energy level. The calculated results reveal that the decrease in transconductance of A...

Ballistic-electron-emission microscopy (BEEM) is used to probe local conduction-band structure in strained Sil .xGq layers of pseudomorphic Sil-xGe#Si heterostmctires. The strain variation produced by a roughened Si l.xGex surface is seen as a variation of splitting between thresholds in BEEM spectroscopy. This splitting is directly related to the strain-induced conduction-band splitting in the...

First-principles calculations of the energetics of the In-terminated GaN~0001!, (0001I ), (101I 1), and (1011) surfaces indicate that In has a substantial effect on the relative energies of formation of these surfaces. Indium-induced changes in the surface energetics enable the formation of inverted hexagonal pyramid defects having (101I 1) facets at the termination of threading defects on the ...

The structure and magnetic properties of an InGaAs/Fe(3)Si superlattice in a cylindrical geometry are investigated by electron microscopy techniques, x-ray diffraction and magnetometry. To form a radial superlattice, a pseudomorphic InGaAs/Fe(3)Si bilayer has been released from its substrate self-forming into rolled-up microtubes. Oxide-free interfaces as well as areas of crystalline bonding ar...

A fully matched Ka-band wideband pseudomorphic highelectron-mobility transistor (PHEMT) 1-W monolithic millimeter-wave integrated circuit (MMIC) high-power amplifier (HPA) without any external circuit is developed. The two-stage HPAs are prepared on 2-mil GaAs substrates with a small chip size of 3.46 2.9 mm. At least 10-dB small-signal gain, 29.5 dBm P 1dB, 31-dBm Psat, and better than 12-dB o...

Spin-polarized field emissions from Fe pseudomorphic ultrathin films on W(001) surfaces are studied by density functional calculations. We found that nearly completely spin-polarized field emission currents can be realized in two and four Fe layers on W(001) and that these systems have the additional advantages of thermal stability and low work functions. The unusually high spin polarizations o...

This paper describes the design and realization of a high performance linear power amplifier in the 2.4GHz band for the IEEE 802.11b/g WLAN (Wireless Local Area Network) and ISM (Industrial Scientific and Medical) applications using a proprietary 0.5um enhancement-mode Pseudomorphic High-Electron-Mobility Transistor (e-pHEMT) technology. The amplifier exhibits a linear power output of 18.5dBm a...

In this paper, the metamorphic high electron mobility transistors (mHEMTs) are investigated numerically and compared with pseudomorphic high electron mobility transistors (pHEMTs). The two-dimensional device simulator, MEDICI, is used to solve the Poisson’s equation and the electron/hole current continuity equations. The influences of d-doping concentration and position, gate width, spacer thic...

As one of the approaches to improve p-HEMT, we studied effect misorientation GaAs substrates on surface morphology, structure, and electrical properties pseudomorphic heterostructures, as well parameters transistors based them. In a single technological cycle, heterostructures were formed vicinal with (100) orientation misoriented by 2 o (110) method MOCVD (MOCVD) in cycle. It has been establis...