scholarly journals Carrier Transport Properties of GAN in High Electric Field

2019 ◽  
Vol 8 (3S) ◽  
pp. 88-93
Keyword(s):  
Electric Field ◽  
Transport Properties ◽  
Carrier Transport ◽  
Impact Ionization ◽  
Maximum Velocity ◽  
Ionization Rate ◽  
High Electric Field ◽  
Electric Field Increase ◽  
Valence Bands ◽  
The Impact

The Monte Carlo (MC) simulation of the carrier transport mechanisms including impact ionization at high electric field in GaN is presented. Two non-parabolic conduction and valence bands were considered for the simulation of transport properties of electron and hole respectively. The carriers’ drift velocity and energy are simulated as a function of applied electric field at room temperature. The maximum velocity of electron is 2.85 × 107 cm/s at 140 kV/cm. The velocity of electron is saturated at 2 × 107 cm/s at electric field greater than 300 kV/cm. In our work, the velocity of hole is 5 × 106 cm/s at 500 kV/cm. Electron energy increases as the electric field increase and fluctuated at electric field greater than 600 kV/cm when impact ionization occurred. The impact ionization rates are obtained by using modified Keldysh equation. The hole impact ionization rate is higher than that of electron. This work also shows higher electron impact ionization coefficient than that of hole at electric field greater than 4.04 MV/cm

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.

Theoretical Prediction of Zinc Blende Phase GaN Avalanche Photodiode Performance Based on Numerically Calculated Electron and Hole Impact Ionization Rate Ratio

1996 ◽  
Vol 423 ◽  
Author(s):  
J. Kolnik ◽  
I. H. Oguzman ◽  
K. F. Brennan ◽  
R. Wang ◽  
P. P. Ruden
Keyword(s):  
Electric Field ◽  
Applied Electric Field ◽  
Impact Ionization ◽  
Full Range ◽  
Avalanche Photodiode ◽  
Ionization Rate ◽  
Zinc Blende ◽  
Valence Bands ◽  
Impact Ionization Rate ◽  
Ionization Rates

AbstractIn this paper, we present the first calculations of the electron and hole initiated interband impact ionization rate in zinc blende phase GaN as a function of the applied electric field strength. The calculations are performed using an ensemble Monte Carlo simulator including the full details of the conduction and valence bands along with a numerically determined, wave-vector dependent interband ionization transition rate determined from an empirical pseudopotential calculation. The first four conduction bands and first three valence bands, which fully comprise the energy range of interest for device simulation, are included in the analysis. It is found that the electron and hole ionization rates are comparable over the full range of applied electric field strengths examined. Based on these calculations an avalanche photodiode, APD, made from bulk zinc blende GaN then would exhibit poor noise and bandwidth performance. It should be noted however, that the accuracy of the band structure employed and the scattering rates is presently unknown since little experimental information is available for comparison. Therefore, due to these uncertainties, it is difficult to unequivocally conclude that the ionization rates are comparable.

Ion-Induced Anomalous Charge Collection Mechanisms in SiC Schottky Barrier Diodes

2015 ◽  
Vol 821-823 ◽  
pp. 575-578 ◽  
Author(s):  
Takahiro Makino ◽  
Manato Deki ◽  
Shinobu Onoda ◽  
Norihiro Hoshino ◽  
Hidekazu Tsuchida ◽  
...  
Keyword(s):  
Electric Field ◽  
Schottky Barrier ◽  
Layer Thickness ◽  
Epitaxial Layer ◽  
Impact Ionization ◽  
Heavy Ion ◽  
Charge Collection ◽  
Static Electric Field ◽  
The Impact ◽  
Lower Electric Field

The charge induced in SiC-SBDs with different epi-layer thicknesses by ion incidence was measured to understand the mechanism of heavy-ion-induced anomalous charge collection in SiC-SBDs. SiC SBD of which epitaxial-layer thicknesses is close to ion range show larger anomalous charge collection than SBD with thicker epi-layer although the former one has lower electric field than the later one. The gains of collected charge from the SBDs suggest that the impact ionization under 0.16 - 0.18 MV/cm of the static electric field in depletion layer is not dominant mechanisms for the anomalous charge collection. It is suggested that the epitaxial-layer thickness and ion-induced transient high electric field are key to understand the anomalous charge collection mechanisms in SBDs.

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.

scholarly journals A Low Impact Ionization Rate Poly-Si TFT with a Current and Electric Field Split Design

Coatings ◽  
2019 ◽  
Vol 9 (8) ◽  
pp. 514 ◽  
Author(s):  
Feng-Tso Chien ◽  
Kuang-Po Hsueh ◽  
Zhen-Jie Hong ◽  
Kuan-Ting Lin ◽  
Yao-Tsung Tsai ◽  
...  
Keyword(s):  
Thin Film ◽  
Electric Field ◽  
Impact Ionization ◽  
Thin Film Transistor ◽  
Ionization Rate ◽  
Field Plate ◽  
Current Path ◽  
Plate Design ◽  
Impact Ionization Rate ◽  
A Current

In this study, a novel low impact ionization rate (low-IIR) poly-Si thin film transistor featuring a current and electric field split (CES) structure with bottom field plate (BFP) and partial thicker channel raised source/drain (RSD) designs is proposed and demonstrated. The bottom field plate design can allure the electron and alter the electron current path to evade the high electric field area and therefore reduce the device IIR and suppress the kink effect. A two-dimensional device simulator was applied to describe and compare the current path, electric field magnitude distributions, and IIR of the proposed structure and conventional devices. In addition, the advantages of a partial thicker channel RSD design are present, and the leakage current of CES-thin-film transistor (TFT) can be reduced and the ON/OFF current ratio be improved, owing to a smaller drain electric field.

Determination of the impact ionization rate of holes in tellurium at 77 K

1979 ◽  
Vol 55 (1) ◽  
pp. 197-202 ◽  
Author(s):  
Z. Dobrovolskis ◽  
W. Hoerstel ◽  
A. Krotkus
Keyword(s):  
Impact Ionization ◽  
Ionization Rate ◽  
Impact Ionization Rate ◽  
The Impact
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