scholarly journals Non Local Impact Ionization Effects in Semiconductor Devices

VLSI Design ◽  
1998 ◽  
Vol 6 (1-4) ◽  
pp. 291-297 ◽  
Author(s):  
Duilio Meglio ◽  
Corrado Cianci ◽  
Aldo Di Carlo ◽  
Paolo Lugli
Keyword(s):  
Carrier Transport ◽  
Impact Ionization ◽  
Semiconductor Devices ◽  
High Energy ◽  
Drift Diffusion ◽  
Non Local ◽  
Local Impact ◽  
Ionization Coefficients ◽  
The Impact ◽  
Space Effects

Impact ionization processes define the breakdown characteristics of semiconductor devices. An accurate description of such phenomenon, however, is limited to very sophisticated device simulators such as Monte Carlo. A new physical model for the impact ionization process is presented, which accounts for dead space effects and high energy carrier transport at a Drift Diffusion level. Such model allows to define universal impact ionization coefficients which are device-geometry independent. By using available experimental data these parameters have been calculated for In0.53Ga0.47As.

Comparison of drift–diffusion model and hydrodynamic carrier transport model for simulation of GaN-based IMPATT diodes

2019 ◽  
Vol 33 (13) ◽  
pp. 1950156 ◽  
Author(s):  
Xiusheng Li ◽  
Lin’an Yang ◽  
Xiaohua Ma
Keyword(s):  
Electric Field ◽  
Diffusion Model ◽  
Carrier Transport ◽  
Impact Ionization ◽  
Transport Model ◽  
Relaxation Effect ◽  
Drift Diffusion Model ◽  
Drift Diffusion ◽  
Impatt Diode ◽  
The Impact

This paper presents a numerical simulation of a Wurtzite-GaN-based IMPATT diode operating at the low-end frequency of terahertz range. Conventional classical drift–diffusion model is independent of the energy relaxation effect at high electric field. However, in this paper, a hydrodynamic carrier transport model including a new energy-based impact ionization model is used to investigate the dc and high-frequency characteristics of an IMPATT diode with a traditional drift–diffusion model as comparison. Simulation results show that the maximum rf power density and the dc-to-rf conversion efficiency are larger for conventional drift–diffusion model because it overestimates the impact ionization rate. Through hydrodynamic simulation we revealed that the impact ionization rates are seriously affected by the high and rapidly varied electric field and the electron energy relaxation effect, which lead to the rf output power density and the dc-to-rf conversion efficiency falls gradually, and a wider operation frequency band is obtained compared with the drift–diffusion model simulation at frequencies over 310 GHz.

Temperature Dependence of Hole Impact Ionization Coefficient in 4H-SiC Photodiodes

2009 ◽  
Vol 615-617 ◽  
pp. 311-314 ◽  
Author(s):  
W.S. Loh ◽  
J.P.R. David ◽  
B.K. Ng ◽  
Stanislav I. Soloviev ◽  
Peter M. Sandvik ◽  
...  
Keyword(s):  
Phonon Scattering ◽  
Impact Ionization ◽  
Positive Temperature Coefficient ◽  
Positive Temperature ◽  
Different Temperatures ◽  
Ionization Coefficients ◽  
Increasing Temperature ◽  
The Impact ◽  
Good Agreement ◽  
Ionization Rates

Hole initiated multiplication characteristics of 4H-SiC Separate Absorption and Multiplication Avalanche Photodiodes (SAM-APDs) with a n- multiplication layer of 2.7 µm were obtained using 325nm excitation at temperatures ranging from 300 to 450K. The breakdown voltages increased by 200mV/K over the investigated temperature range, which indicates a positive temperature coefficient. Local ionization coefficients, including the extracted temperature dependencies, were derived in the form of the Chynoweth expression and were used to predict the hole multiplication characteristics at different temperatures. Good agreement was obtained between the measured and the modeled multiplication using these ionization coefficients. The impact ionization coefficients decreased with increasing temperature, corresponding to an increase in breakdown voltage. This result agrees well with the multiplication characteristics and can be attributed to phonon scattering enhanced carrier cooling which has suppressed the ionization process at high temperatures. Hence, a much higher electric field is required to achieve the same ionization rates.

Determination of Impact Ionization Coefficients Measured from 4H Silicon Carbide Avalanche Photodiodes

2007 ◽  
Vol 556-557 ◽  
pp. 339-342 ◽  
Author(s):  
W.S. Loh ◽  
C. Mark Johnson ◽  
J.S. Ng ◽  
Peter M. Sandvik ◽  
Steve Arthur ◽  
...  
Keyword(s):  
Impact Ionization ◽  
Avalanche Photodiodes ◽  
Submicron Devices ◽  
Illuminating Light ◽  
Factor Data ◽  
Ionization Coefficients ◽  
P Type ◽  
Dark Currents ◽  
The Impact

Hole initiated avalanche multiplication characteristics of 4H-SiC avalanche photodiodes have been studied. The diodes had n+-n-p SiC epitaxial layers grown on a p-type substrate. These 1 mm2 devices had very low dark currents and exhibited sharp breakdown at voltages of approximately 500V. The diodes multiplication characteristics appeared to be identical when the wavelength of the illuminating light from the top varied from 288 to 325nm, implying that almost pure hole initiated multiplication was occurring. The multiplication factor data were modelled using a local multiplication model with impact ionization coefficients of 4H-SiC reported by various authors. The impact ionization coefficients extracted from submicron devices by Ng et al. were found to give accurate predictions for multiplication factors within the uncertainties of the doping levels. This result suggests that their ionization coefficients can be applied to thicker bulk 4H-SiC structures.

Mean multiplication gain and excess noise factor of GaN and Al0.45Ga0.55N avalanche photodiodes

2020 ◽  
Vol 92 (1) ◽  
pp. 10301
Author(s):  
Tat Lung Wesley Ooi ◽  
Pei Ling Cheang ◽  
Ah Heng You ◽  
Yee Kit Chan
Keyword(s):  
Electric Field ◽  
Impact Ionization ◽  
Avalanche Photodiodes ◽  
Monte Carlo Model ◽  
Noise Factor ◽  
Excess Noise ◽  
Excess Noise Factor ◽  
Multiplication Gain ◽  
Ionization Coefficients ◽  
The Impact

In this work, Monte Carlo model is developed to investigate the avalanche characteristics of GaN and Al0.45Ga0.55N avalanche photodiodes (APDs) using random ionization path lengths incorporating dead space effect. The simulation includes the impact ionization coefficients, multiplication gain and excess noise factor for electron- and hole-initiated multiplication with a range of thin multiplication widths. The impact ionization coefficient for GaN is higher than that of Al0.45Ga0.55N. For GaN, electron dominates the impact ionization at high electric field while hole dominate at low electric field whereas Al0.45Ga0.55N has hole dominate the impact ionization at higher field while electron dominate the lower field. In GaN APDs, electron-initiated multiplication is leading the multiplication gain at thinner multiplication widths while hole-initiated multiplication leads for longer widths. However for Al0.45Ga0.55N APDs, hole-initiated multiplication leads the multiplication gain for all multiplication widths simulated. The excess noise of electron-initiated multiplication in GaN APDs increases as multiplication widths increases while the excess noise decreases as the multiplication widths increases for hole-initiated multiplication. As for Al0.45Ga0.55N APDs, the excess noise for hole-initiated multiplication increases when multiplication width increases while the electron-initiated multiplication increases with the same gradient at all multiplication widths.

Lifetime Calculations of MOSFET’s Using Depth-Dependent Non-Local Impact Ionization

1993 ◽  
pp. 469-472
Author(s):  
M. J. van Dort ◽  
J. W. Slotboom ◽  
G. Streutker ◽  
P. H. Woerlee
Keyword(s):  
Impact Ionization ◽  
Non Local ◽  
Local Impact

Comprehensive Study of Impact Ionization Coefficients of 4H-SiC

2004 ◽  
Vol 815 ◽  
Author(s):  
T. Hatakeyama ◽  
T. Watanabe ◽  
K. Kojima ◽  
N. Sano ◽  
T. Shinohe ◽  
...  
Keyword(s):  
Electronic Structure ◽  
Impact Ionization ◽  
Avalanche Breakdown ◽  
Doping Density ◽  
Electric Field Dependence ◽  
Saturation Velocity ◽  
Large Anisotropy ◽  
Ionization Coefficients ◽  
The Impact ◽  
Comprehensive Study

AbstractThe electric field dependence and anisotropy of the impact ionization coefficients of 4H-SiC are investigated by means of the avalanche breakdown behavior of p+n diodes. The breakdown voltages as a function of doping density and the multiplication factors of a leakage current are obtained using p+n diode fabricated on (0001) and (1120) 4H-SiC epitaxial wafers. The obtained impact ionization coefficients show large anisotropy; the breakdown voltage of a p+n diode on (1120) wafer is 60% of that on (0001) wafer. We have shown that anisotropy of the impact ionization coefficients is attributable to the anisotropy of saturation velocity originated from the electronic structure of 4H-SiC.

scholarly journals In Situ Study of the Impact of Aberration-Corrected Electron-Beam Lithography on the Electronic Transport of Suspended Graphene Devices

Nanomaterials ◽  
2020 ◽  
Vol 10 (4) ◽  
pp. 666
Author(s):  
Naomi Mizuno ◽  
Fernando Camino ◽  
Xu Du
Keyword(s):  
Electron Beam ◽  
Electronic Transport ◽  
Electron Beam Lithography ◽  
High Energy ◽  
Suspended Graphene ◽  
Local Exposure ◽  
Non Local ◽  
The Impact ◽  
Aberration Corrected

The implementation of aberration-corrected electron beam lithography (AC-EBL) in a 200 keV scanning transmission electron microscope (STEM) is a novel technique that could be used for the fabrication of quantum devices based on 2D atomic crystals with single nanometer critical dimensions, allowing to observe more robust quantum effects. In this work we study electron beam sculpturing of nanostructures on suspended graphene field effect transistors using AC-EBL, focusing on the in situ characterization of the impact of electron beam exposure on device electronic transport quality. When AC-EBL is performed on a graphene channel (local exposure) or on the outside vicinity of a graphene channel (non-local exposure), the charge transport characteristics of graphene can be significantly affected due to charge doping and scattering. While the detrimental effect of non-local exposure can be largely removed by vigorous annealing, local-exposure induced damage is irreversible and cannot be fixed by annealing. We discuss the possible causes of the observed exposure effects. Our results provide guidance to the future development of high-energy electron beam lithography for nanomaterial device fabrication.

Temperature dependence of the impact ionization coefficients in GaAs, cubic SiC, and zinc-blende GaN

2003 ◽  
Vol 94 (1) ◽  
pp. 423-430 ◽  
Author(s):  
Louis Tirino ◽  
Michael Weber ◽  
Kevin F. Brennan ◽  
Enrico Bellotti ◽  
Michele Goano
Keyword(s):  
Temperature Dependence ◽  
Impact Ionization ◽  
Zinc Blende ◽  
Ionization Coefficients ◽  
The Impact
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