INFLUENCE OF DENSITY, OCCUPANCY AND LOCATION OF ELECTRON TRAPS ON SHOT NOISE IN NONDEGENERATE QUASIBALLISTIC TRANSPORT

2002 ◽  
Vol 02 (03) ◽  
pp. L243-L251 ◽  
Author(s):  
B. G. VASALLO ◽  
J. MATEOS ◽  
D. PARDO ◽  
T. GONZÁLEZ
Keyword(s):  
Monte Carlo ◽  
Active Region ◽  
Shot Noise ◽  
Noise Level ◽  
Current Fluctuations ◽  
Potential Minimum ◽  
Ensemble Monte Carlo ◽  
Poisson Solver ◽  
Monte Carlo Simulator ◽  
Ballistic Case

An ensemble Monte Carlo simulator self-consistently coupled with a Poisson solver is used to study the influence of the density, occupancy and location of electrons traps on the current fluctuations in nondegenerate quasiballistic structures. Transport and noise are found to depend significantly on the density and location of the traps. In particular, the presence of traps increases the noise level as compared with the purely ballistic case. The nonuniformity of the trap occupancy profiles along the active region of the structures affects markedly (specially for low trap densities) the dependence of shot noise on the applied voltage. The location of the traps with respect to the potential minimum appearing in the structures because of the presence of space charge determines their influence on the noise level, fact which can be of help to identify the trap position.

scholarly journals Monte Carlo Investigation of Shot-noise Suppression in Nondegenerate Ballistic and Diffusive Transport Regimes

2000 ◽  
Vol 53 (1) ◽  
pp. 3 ◽  
Author(s):  
L. Reggiani ◽  
A. Reklaitis ◽  
T. González ◽  
J. Mateos ◽  
D. Pardo ◽  
...  
Keyword(s):  
Monte Carlo ◽  
Active Region ◽  
Inelastic Scattering ◽  
Shot Noise ◽  
Noise Suppression ◽  
Signal To Noise Ratio ◽  
Diffusive Transport ◽  
Poisson Solver ◽  
Diffusive Regime ◽  
Shot Noise Suppression

We review recent theoretical investigations of shot-noise suppression in nondegenerate semiconductor structures surrounded by two contacts acting as thermal reservoirs. Calculations make use of an ensemble Monte Carlo simulator self-consistently coupled with a one-dimensional Poisson solver. By taking the doping of the injecting contacts and the applied voltage as variable parameters, the influence of elastic and inelastic scattering as well as of tunneling between heterostructures in the active region is investigated. In the case of a homogeneous structure at T = 300 K the transition from ballistic to diffusive transport regimes under different contact injecting statistics is analysed and discussed. Provided significant space-charge effects take place inside the active region, long-range Coulomb interaction is found to play an essential role in suppressing shot noise at applied voltages much higher than the thermal value. In the elastic diffusive regime, momentum space dimensionality is found to modify the suppression factor γ, which within numerical uncertainty takes values respectively of about ⅓, ½ and 0·7 in the 3D, 2D and 1D cases. In the inelastic diffusive regime, shot noise is suppressed to the thermal value. In the case of single and multiple barrier non-resonant heterostructures made by GaAs/AlGaAs at 77 K, the mechanism of suppression is identified in the carrier inhibition to come back to the emitter contact after having been reflected from a barrier. This condition is realised in the presence of strong inelastic scattering associated with emission of optical phonons. At increasing applied voltages for a two-barrier structure, shot noise is suppressed up to about a factor of 0·50 in close analogy with the corresponding resonant barrier-diode. For an increasing number of barriers, shot noise is found to be systematically suppressed to a more significant level by following approximately a 1/(N + 1) behaviour, N being the number of barriers. This mechanism of suppression is expected to conveniently improve the signal-to-noise ratio of these devices.

Multi-Subband Ensemble Monte Carlo Simulator for Nanodevices in the End of the Roadmap

2020 ◽  
pp. 438-445 ◽  
Author(s):  
Carlos Sampedro ◽  
Cristina Medina-Bailon ◽  
Luca Donetti ◽  
Jose Luis Padilla ◽  
Carlos Navarro ◽  
...  
Keyword(s):  
Monte Carlo ◽  
Ensemble Monte Carlo ◽  
Monte Carlo Simulator

scholarly journals Implementation of Band-to-Band Tunneling Phenomena in a Multisubband Ensemble Monte Carlo Simulator: Application to Silicon TFETs

2017 ◽  
Vol 64 (8) ◽  
pp. 3084-3091 ◽  
Author(s):  
Cristina Medina-Bailon ◽  
Jose L. Padilla ◽  
Carlos Sampedro ◽  
Cem Alper ◽  
Francisco Gamiz ◽  
...  
Keyword(s):  
Monte Carlo ◽  
Tunneling Phenomena ◽  
Ensemble Monte Carlo ◽  
Band To Band Tunneling ◽  
Monte Carlo Simulator

MONTE-CARLO SIMULATION OF ULTRA-THIN FILM SILICON-ON-INSULATOR MOSFETs

2013 ◽  
Vol 22 (01) ◽  
pp. 1350001
Author(s):  
FRANCISCO GÁMIZ ◽  
CARLOS SAMPEDRO ◽  
LUCA DONETTI ◽  
ANDRES GODOY
Keyword(s):  
Monte Carlo ◽  
Ground Plane ◽  
Silicon On Insulator ◽  
Slab Thickness ◽  
Short Channel ◽  
Fully Depleted ◽  
Ensemble Monte Carlo ◽  
Soi Devices ◽  
Monte Carlo Simulator ◽  
The Impact

State-of-the-Art devices are approaching to the performance limit of traditional MOSFET as the critical dimensions are shrunk. Ultrathin fully depleted Silicon-on-Insulator transistors and multi-gate devices based on SOI technology are the best candidates to become a standard solution to overcome the problems arising from such aggressive scaling. Moreover, the flexibility of SOI wafers and processes allows the use of different channel materials, substrate orientations and layer thicknesses to enhance the performance of CMOS circuits. From the point of view of simulation, these devices pose a significant challenge. Simulations tools have to include quantum effects in the whole structure to correctly describe the behavior of these devices. The Multi-Subband Monte Carlo (MSB-MC) approach constitutes today's most accurate method for the study of nanodevices with important applications to SOI devices. After reviewing the main basis of MSB-MC method, we have applied it to answer important questions which remain open regarding ultimate SOI devices. In the first part of the chapter we present a thorough study of the impact of different Buried OXide (BOX) configurations on the scaling of extremely thin fully depleted SOI devices using a Multi-Subband Ensemble Monte Carlo simulator (MS-EMC). Standard thick BOX, ultra thin BOX (UTBOX) and UTBOX with ground plane (UTBOX+GP) solutions have been considered in order to check their influence on short channel effects (SCEs). The simulations show that the main limiting factor for downscaling is the DIBL and the UTBOX+GP configuration is the only valid one to downscale SGSOI transistors beyond 20 nm channel length keeping the silicon slab thickness above the theoretical limit of 5 nm, where thickness variability and mobility reduction would play an important role. In the second part, we have used the multisubband Ensemble Monte Carlo simulator to study the electron transport in ultrashort DGSOI devices with different confinement and transport directions. Our simulation results show that transport effective mass, and subband redistribution are the main factors that affect drift and scattering processes and, therefore, the general performance of DGSOI devices when orientation is changed

Optimisation and parallelisation of a 2D MOSFET multi-subband ensemble Monte Carlo simulator

2012 ◽  
Vol 27 (4) ◽  
pp. 483-492 ◽  
Author(s):  
Raúl Valín ◽  
Carlos Sampedro ◽  
Natalia Seoane ◽  
Manuel Aldegunde ◽  
Antonio Garcia-Loureiro ◽  
...  
Keyword(s):  
Monte Carlo ◽  
Ensemble Monte Carlo ◽  
Monte Carlo Simulator
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