Dynamic Monte Carlo study of isolated-gate InAs/AlSb HEMTs

Abstract

In this work, by means of Monte Carlo simulations, the static and dynamic behavior of isolated-gate InAs/AlSb high electron mobility transistors (Sb-HEMTs) has been studied and compared with experimental results. The influence of the existence of a native oxide under the gate, the value of the surface charges in the gate recess and the possible variation of electron sheet carrier density, ns, has been studied. A decrease in the gate-source capacitance, transconductance and intrinsic cutoff frequency is observed because of the presence of the native oxide, while changes in the value of the surface charges in the recess only introduce a threshold voltage shift. The increase of ns shifts the maximum of the transconductance and intrinsic cutoff frequency to higher values of drain current and improves the agreement with the experimental results.

Relaxation dynamics and residual strain in metamorphic AlSb on GaAs

“…Second, metamorphic layers are most often not 100% free of strain, but as AlSb has a slightly larger lattice parameter than GaSb (6.1355 Å vs 6.0959 Å , 0.6%), it would, in principle, be possible to grow strain free GaSb on top of metamorphic AlSb if a small compressive strain remains in the AlSb. Metamorphic AlSb is also being actively studied for the fabrication of high electron mobility transistors [6][7][8] and mid infrared laser sources. 9 The sample was epitaxially grown on GaAs (001) by solid source molecular beam epitaxy.…”

Monte Carlo study of the noise performance of isolated-gate InAs HEMTs

“…Second, a V GS shift of 0.03 V has been included. This shift is related to i) the possible volume charges within the oxide, ii) the semiconductor-metal work function difference (both not considered in the simulations), and ii) the possible shift introduced by variations on σ recess [5]. Fig.…”

“…Once the experimental DC behavior has been reproduced by MC simulations, the small signal equivalent circuit (SSEC) parameters have been obtained for V DS =0.2 V [5]. MC results for SSEC parameters have been extracted from the Y-parameters calculated by Fourier analysis of the transistor current response to voltage steps applied at the gate and drain contacts [9].…”

“…The noise results will be presented for a device with 100 m width. This work has been partially supported by the Dirección General de Investigación (MICINN) and FEDER through Project TEC2010-15413 and by the Consejería de Educación, Junta de Castilla y León through Projects SA019A08 and GR270) 3 , has been considered in the simulations after testing different values of the dielectric constant and thickness of the native oxide [5].…”

“…Previously, in order to validate our simulator, the experimental measurements of DC characteristics and small signal equivalent circuit have been reproduced with our model [5]. For this work, an ensemble MC simulator self-consistently coupled with a two-dimensional Poisson solver [4,6] properly adapted to work with narrow band-gap channel HEMTs [7] has been used.…”