Monte Carlo evaluation of GaN THz Gunn diodes

Lee, Wen Zhao; Ong, Duu Sheng; Choo, Kan Yeep; Yilmazoglu, Oktay; Hartnagel, H.L.

doi:10.1088/1361-6641/ac2b4d

Cited by 6 publications

(3 citation statements)

References 40 publications

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“…However, the operating frequency of the Gunn diode is generally higher than that of the IMPATT diode for the same device size. The Monte Carlo model predicts a GaN Gunn diode with a transit length of 500 nm capable of operating at frequencies up to 625 GHz with an estimated output power of 3.0 W. 44 Akhbar et al 45 proposed GaAs-based Gunn diodes with notch-δ-doped structures, which produces a current harmonic amplitude of 29.4 × 10 7 A/m 2 at a fundamental frequency of 262 GHz. Its second and third harmonic signals reach 512 and 769 GHz, respectively.…”

Section: G Comparison With Other Thz Sourcesmentioning

confidence: 99%

AlGaN/GaN bilateral IMPATT device by two-dimensional electron gas for terahertz application

Dai,

Li,

Gao

et al. 2024

Journal of Applied Physics

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A novel bilateral impact-ionization-avalanche-transit-time (BIMPATT) diode based on AlGaN/GaN two-dimensional electron gas is proposed in this article. The BIMPATT is compatible with the available GaN high electron mobility transistor (HEMT) manufacturing process and has a shorter actual electron transit distance than existing HEMT-like IMPATT (HIMPATT) diodes. Compared with the same-sized HIMPATT, the optimum frequency of BIMPATT rises from 320 to 420 GHz and possesses a far wider operating frequency band, especially in the near 0.9 THz range. The maximum DC-RF conversion efficiency rises from 12.9% to 17.6%. The maximum RF power of BIMPATT is 3.18 W/mm, which is similar to 3.12 W/mm of the HIMPATT. Furthermore, our simulation demonstrated that the characteristics of BIMPATT are significantly affected by the length of anode and the thickness of the AlGaN barrier layer. The effects of ohmic contact resistance and background impurities on BIMPATT are also taken into account. This paper provides a reference for the design and characteristics enhancement of the lateral IMPATT devices.

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Section: G Comparison With Other Thz Sourcesmentioning

confidence: 99%

AlGaN/GaN bilateral IMPATT device by two-dimensional electron gas for terahertz application

Dai,

Li,

Gao

et al. 2024

Journal of Applied Physics

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“…The motion of the ensemble carriers in the diode are successively calculated with a small-time step of 1 fs to enable the dynamic of the electrons to be modelled accurately. This allows for the calculation of the temporal and spatial characteristics of electron transport in the Gunn diodes, which includes details of electron velocity as well as electron energy distribution to be recorded as a function of position and time in the device [17]. The simulation of the EMC model is started with the configuration of the device structure using a 1D mesh size of 1 nm, where electrons are distributed according to the doping profile with more than 10 5 particles representing the thermally equilibrial electrons in the device.…”

Section: Monte Carlo Modelmentioning

confidence: 99%

Analysis of notch-δ-doped GaAs-based Gunn diodes

Akhbar¹,

Ong²

2022

J. Phys. D: Appl. Phys.

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The performances of GaAs-based Gunn diodes with a notch-δ-doped structure have been studied in this work. The δ-doped effect has been analysed using Monte Carlo modelling in terms of temporal evolution of current density, electric field profile, electron energy, mean velocity, and occupancy in Γ and higher valleys. The presence of a δ-doped layer after the notch caused a significant increase in the harmonic current amplitude of the device, where the growth of high field domain can be attributed to a slow electron track due to the well-known Gunn effect and an additional fast electron track which appears over a short time window when the domain is reaching the anode. An optimised GaAs notch-δ-doped structure with 700 nm device length including 100 nm notch and 5 nm δ-doped layer can generate signals at fundamental frequency of 262 GHz with a current harmonic amplitude of 29.4×107 A/m2, which is almost twice of that without δ-doped layer. Its second and third harmonic signals are found substantial reaching into the THz range of 512 GHz and 769 GHz.

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“…However, the small bandgap of such GaAs and InP based semiconductors is an intrinsic limitation for increasing the generated power. That is why with the recent advances in the growth of high quality GaN, thanks to its large bandgap and reasonable NDR, this semiconductor is becoming a promising candidate for the fabrication of high-power high-frequency Gunn diodes Simulations of GaN-based diodes indicate the possibility of achieving Gunn oscillations with frequencies above 500 GHz, faster than in traditional semiconductors due to the short relaxation time of GaN [7]- [12]. Furthermore, the NDR of GaN has been observed and indirect evidence of current oscillations has been obtained [13]- [15], which allows us to believe on the practical feasibility of high-power high-frequency GaN Gunn diodes.…”

Section: Introductionmentioning

confidence: 99%

A Deep Learning-Monte Carlo Combined Prediction of Side-Effect Impact Ionization in Highly Doped GaN Diodes

García-Sánchez

Rengel

Pérez

et al. 2023

IEEE Trans. Electron Devices

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The existence of leakage current pathways leading to the appearance of impact ionization and the potential device breakdown in planar Gunn GaN diodes is analyzed by means of a combined Monte Carlo-deep learning approach. Front-view (lateral) Monte Carlo simulations of the devices show the appearance of a high-field hotspot at the anode corner of the etched region, just at the boundaries between the dielectric, the GaN-doped layer, and the buffer. Thus, if the isolation created by the etched trenches is not complete, a relevant hot carrier population within the buffer is observed at sufficiently high applied voltages, provoking the appearance of a very significant number of impact ionizations and the consequent avalanche process before the onset of Gunn oscillations. A neural network trained from Monte Carlo simulations allows predicting with extremely good precision the breakdown voltage of the diodes depending on the doping of the GaN active layer, the permittivity of the isolating dielectric, and the lattice temperature. Low doping, high temperature and high permittivity provide larger operational voltages, which implies a tradeoff with the conditions required to achieve THz Gunn oscillations at low voltages.

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Monte Carlo evaluation of GaN THz Gunn diodes

Cited by 6 publications

References 40 publications

AlGaN/GaN bilateral IMPATT device by two-dimensional electron gas for terahertz application

AlGaN/GaN bilateral IMPATT device by two-dimensional electron gas for terahertz application

Analysis of notch-δ-doped GaAs-based Gunn diodes

A Deep Learning-Monte Carlo Combined Prediction of Side-Effect Impact Ionization in Highly Doped GaN Diodes

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