WZ-GaN based Quasi-Read ATT diode: A novel high-power THz device with reduced parasitic resistance

doi:10.1109/EDSSC.2010.5713780

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WZ-GaN based Quasi-Read ATT diode: A novel high-power THz device with reduced parasitic resistance

Proceedings Article•DOI•

WZ-GaN based Quasi-Read ATT diode: A novel high-power THz device with reduced parasitic resistance

Moumita Mukherjee¹•Institutions (1)

University of Calcutta¹

01 Dec 2010-pp 1-4

TL;DR: In this paper, a simulation of the single drift region and Quasi-Read type hexagonal GaN-based IMPATT devices for Terahertz frequency operation was carried out.

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Abstract: Simulation investigation is carried out on the single drift region and Quasi-Read type hexagonal GaN based IMPATT devices for Terahertz frequency operation. It is observed that Quasi-Read GaN IMPATT may generate a RF power density of ∼43×1010 Wm−2 with an efficiency of 20%, whereas its flat profile counterpart is capable of delivering a power density of 31×1010 Wm−2 with an efficiency of 17%. The total parasitic series resistance, including the effects of ohmic contact resistances, has been found to be a major problem that reduces the RF power output of the THz IMPATTs significantly. The study reveals that the value of RS decreases by 30% as the doping profile of the diode changes from flat to Quasi-Read type with the incorporation of the charge bump. This study establishes the advantages of Quasi-Read type IMPATT over its flat profile counterpart to realize a high-power source in the THz regime.

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Journal Article•DOI•

Photosensitivity Analysis of Gallium Nitride and Silicon Carbide Terahertz IMPATT Oscillators: Comparison of Theoretical Reliability and Study on Experimental Feasibility

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Moumita Mukherjee, Nilratan Mazumder, S.K. Roy

01 Sep 2008-IEEE Transactions on Device and Materials Reliability

TL;DR: In this article, the performance of the terahertz-frequency (1.0 THz) characteristics of widebandgap (WBG) wurtzite (Wz)-GaN-and 4H-SiC-based p++nn++-type single-drift-region (SDR) impact avalanche transit time (IMPATT) devices (normal and photoilluminated) is compared through a simulation scheme.

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Abstract: Reliability of terahertz-frequency (~1.0 THz) characteristics of wide-bandgap (WBG) wurtzite (Wz)-GaN- and 4H-SiC-based p++nn++-type single-drift-region (SDR) impact avalanche transit time (IMPATT) devices (normal and photoilluminated) is compared through a simulation scheme. The simulation experiment reveals that an RF power density of 3.37 times 1011 W middotm-2 (efficiency of 18.2%) at around 1.126 THz may be realized from the optimized unilluminated GaN IMPATT device, whereas the unilluminated 4H-SiC IMPATT device is expected to generate an RF power density of 1.35 times 1011 W middotm-2 (efficiency of 9%) at 1.05 THz. However, the parasitic series resistance reduces the maximum exploitable power density from the terahertz devices. Under optical illumination, additional photogenerated carriers are created in the devices, and these carriers change the admittance and negative resistance properties of the terahertz IMPATT diodes. The performance modulation of the terahertz devices is simulated, and the results are compared in this paper. Under external radiation, the operating frequencies of the GaN- and SiC-based diodes are found to shift upward by 6.0 and 40.0 GHz, respectively, with degradation of maximum output-power density level and device negative resistance. The extensive simulation experiments establish that, although the photosensitivity of the 4H-SiC-based IMPATT device is better than its GaN counterpart, the overall terahertz performance of the unilluminated GaN IMPATT device is far better than the 4H-SiC-based device, particularly in terms of output power and efficiency. The simulation results and the proposed experimental methodology presented here can be used for realizing optically tuned WBG IMPATT oscillators for terahertz communication.

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56 citations

"WZ-GaN based Quasi-Read ATT diode: ..." refers background or methods in this paper

...The validity of this simulation method was reported earlier [1]....
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...A modified drift-diffusion simulation scheme, developed by the author, has been adopted for this purpose [1]....
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...Author has already predicted the prospects of SiC and GaN IMPATTs in the THz region [1]....
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...susceptance (B) plots), negative resistance and quality factor (-Q =B/-G) of the optimized GaN SDR diodes are determined by Gummel-Blue approach after satisfying the appropriate boundary conditions [1]....
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Journal Article•DOI•

Measurement of series resistance in IMPATT diodes

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M.G. Adlerstein¹, L.H. Holway, S.L.G. Chu•Institutions (1)

Raytheon¹

01 Feb 1983-IEEE Transactions on Electron Devices

TL;DR: In this paper, the electrical series resistance of an IMPATT diode was measured based on the oscillation threshold bias current of the diode in a standard circuit and applied to GaAs diodes near 40 GHz.

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Abstract: A new method is given for determining the electrical series resistance of an IMPATT diode. The measurement is based on observation of the oscillation threshold bias current for a diode in a standard circuit. The method is applied to GaAs diodes near 40 GHz. The values obtained are used to quantitatively explain other performance characteristics of the diodes.

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53 citations

"WZ-GaN based Quasi-Read ATT diode: ..." refers background or methods in this paper

...The diode total negative conductance (-G) and susceptance (B) is calculated from the following expressions: -G =-ZR / ((ZR) 2 + (ZX) (2)) and B = -ZX / ((ZR) 2 + (ZX) (2)) (1) -G and B are functions of RF voltage (VRF) and frequency (ω) such that the steady state condition for oscillation is given by [5]: g (ω) = – G (ω) – {B (ω)}(2) RS (ω) (2) where, g is load conductance....
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...The authors have evaluated RS from the admittance characteristics using the realistic analysis of Gummel-Blue and Adlerstein et al [5] without any drastic assumption....
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