Effect of the T-gate on the performance of recessed HEMTs. A Monte Carlo analysis

Abstract

A microscopic study of 0.1 µm recessed gate δ-doped AlInAs/GaInAs HEMTs has been performed by using a semiclassical Monte Carlo device simulation. The geometry and layer structure of the simulated HEMT is completely realistic, including recessed gate and δ-doping configuration. The usual T-gate technology is used to improve the device characteristics by reducing the gate resistance. For first time we take into account in the Monte Carlo simulations the effect of the T-gate and the dielectric used to passivate the device surface, which affects considerably the electric field distribution inside the device. The measured I d -V ds characteristics of a real device are favourably compared with the simulation results. When comparing the complete simulation with the case in which Poisson equation is solved only inside the semiconductor, we find that even if the static I -V characteristics remain practically unchanged, important differences appear in the dynamic and noise behaviour, reflecting the influence of an additional capacitance.

THz operation of self-switching nano-diodes and nano-transistors

“…The transport model locally takes into account the effect of degeneracy and electron heating by using the rejection technique and the self-consistent calculation of the local electronic temperature and Fermi level 12 . The surface charges appearing at the boundaries of the semiconductors in contact with dielectrics are also considered in the model 13 . The validity of this approach has been checked in previous works by means of the comparison with experimental results of static characteristics, small signal behavior and noise performance of a 0.1 m gate AlInAs/InGaAs lattice matched HEMT.…”

Isolated-gate InAs/AlSb HEMTs: A Monte Carlo study

“…In order to compare the behaviour of SG and IG Sb-HEMTs we have used a semi-classical ensemble MC simulator self-consistently coupled with a 2D Poisson solver (4,5), adequately modified to properly model such narrow band-gap HEMTs (6). We will focus on biases lower than 0.3 V, where the dynamic behaviour of the transistors is expected to be optimal.…”

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

“…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.…”