• The Journal of Korean Institute of Communications and Information Sciences
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• v.24 no.10A
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• pp.1579-1587
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• 1999

Bias-dependent noise models of $0.2\mu\textrm{m}$ gate length P-HEMT's which are scalable with gate width are proposed. To predict S-parameters of the P-HEMT's the intrinsic parameters except for $\tau$ subtracted the offsets introduced in this paper are normalized to the gate width and then scaled. The small-signal model parameters are expressed as fitting functions of the drain current to $\textrm{I}_{dss}$ ratio and gate width. In addition, to estimate accurately noise parameters the noise temperature $\textrm{T}_{g}$ of the intrinsic resistance, the equivalent noise conductance $\textrm{G}_{ni}$ of the gate current noise source, and the equivalent noise conductance $\textrm{G}_{no}$ of the drain current noise source are adopted as the noise model parameters. The extracted values of $\textrm{T}_{g}$ are nearly independent of drain current and gate width and their average is around the ambient temperature. The extracted values of $\textrm{G}_{ni}$ are small enough to be neglected to the circuit characteristics. From the comparison of the noise model with only $\textrm{G}_{no}$ and that having $\textrm{T}_{g}$, $\textrm{G}_{ni}$ and $\textrm{G}_{no}$ to the measured data it is fund that even the former model is in good agreement with the measured noise parameters. Thus, from a practical point of view the noise model having only the drain current noise source is confirmed as a scalable bias-dependent model.

• ETRI Journal
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• v.31 no.3
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• pp.342-344
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• 2009

From a hydrodynamic device simulation for the pseudomorphic high electron mobility transistors (pHEMTs), we observe an increase of maximum extrinsic transconductance and a decrease of source-drain capacitances. This gives rise to an enhancement of the switching speed and isolation characteristics as the upper-to-lower planar-doping ratios (UTLPDR) increase. On the basis of simulation results, we fabricate single-pole-double-throw transmitter/receiver monolithic microwave integrated circuit (MMIC) switches with the pHEMTs of two different UTLPDRs (4:1 and 1:2). The MMIC switch with a 4:1 UTLPDR shows about 2.9 dB higher isolation and approximately 2.5 times faster switching speed than those with a 1:2 UTLPDR.

• Proceedings of the IEEK Conference
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• 1999.11a
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• pp.295-298
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• 1999

AlGaAs/InGaAs power P-HEMTS (Pseudo-morphic High Electron Mobility Transistors) with 1.0-${\mu}{\textrm}{m}$ gate length for PCS applications have been fabricated. We adopted single heterojunction P-HEMT structure with two Si-delta doped layer to obtain higher current density. It exhibits a maximum current density of 512㎃/mm, an extrinsic transconductance of 259mS/mm, and a gate to drain breakdown voltage of 12.0V, respectively. The device exhibits a power density of 657㎽/mm, a maximum power added efficiency of 42.1%, a linear power gain of 9.85㏈ respectively at a drain bias of 6.0V, gate bias of 0.6V and an operation frequency of 1.765㎓.

• JSTS:Journal of Semiconductor Technology and Science
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• v.13 no.4
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• pp.342-354
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• 2013

The aim of this work is to investigate and study the quantum effects in the modeling of nanoscale symmetric double-gate InAlAs/InGaAs/InP HEMT (High Electron Mobility Transistor). In order to do so, the carrier concentration in InGaAs channel at gate lengths ($L_g$) 100 nm and 50 nm, are modelled by a density gradient model or quantum moments model. The simulated results obtained from the quantum moments model are compared with the available experimental results to show the accuracy and also with a semi-classical model to show the need for quantum modeling. Quantum modeling shows major variation in electron concentration profiles and affects the device characteristics. The two triangular quantum wells predicted by the semi-classical model seem to vanish in the quantum model as bulk inversion takes place. The quantum effects thus become essential to incorporate in nanoscale heterostructure device modeling.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.18 no.6
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• pp.195-200
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• 2018

A W-band frequency octupler is implemented on 100-nm GaAs pHEMT process. The fabricated octupler can be used as a local oscillator or a signal source of W-band transceivers. Three common-source doublers are connected in cascade to multiply an input signal of 10.75 GHz to 83 GHz. A common-source amplifier is followed for each doubler to improve the conversion gain and suppress the unwanted harmonics. The fabricated octupler showes high output of more than 6 dBm in the 80 - 84 GHz band and achieved excellent spurious suppression performance over 20 dBc.

• Journal of the Institute of Electronics Engineers of Korea SD
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• v.48 no.11
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• pp.1-8
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• 2011

One of the most important parameters that limit maximum output power of transistor is breakdown. InAlAs/InGaAs/GaAs Metamorphic HEMTs (MHEMTs) have some advantages, especially for cost, compared with InP-based ones. However, GaAs-based MHEMTs and InP-based HEMTs are limited by lower breakdown voltage for output power even though they have good microwave and millimeter-wave frequency performance with lower minimum noise figure. In this paper, InAlAs/$In_xGa_{1-x}As$/GaAs MHEMTs are simulated and analyzed for breakdown. The parameters affecting breakdown are investigated in the fabricated 0.1-${\mu}m$ ${\Gamma}$-gate MHEMT device having the modulation-doped $In_{0.52}Al_{0.48}As/In_{0.53}Ga_{0.47}As$ heterostructure on the GaAs wafer using the hydrodynamic transport model of a 2D commercial device simulator. The impact ionization and gate field effect in the fabricated device including deep-level traps are analyzed for breakdown. In addition, Indium mole-fraction-dependent impact ionization rates are proposed empirically for $In_{0.52}Al_{0.48}As/In_xGa_{1-x}As$/GaAs MHEMTs.

• Journal of the Korean Vacuum Society
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• v.22 no.6
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• pp.335-340
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• 2013

This paper is for the simulation design to enhance the breakdown voltage of MHEMTs with an InP-etchstop layer. Gate-recess and channel structures has been simulated and analyzed for the breakdown of the MHEMT devices. The fully removed recess structure at the drain side of MHEMT shows that the breakdown voltage enhances from 2 V to almost 4 V as the saturation current at gate voltage of 0 V is reduced from 90 mA to 60 mA at drain voltage of 2 V. This is because the electron-captured negatively fixed charges at the drain-side interface between the InAlAs barrier and the $Si_3N_4$ passivation layers deplete the InGaAs channel layer more and thus decreases the electron current passing the channel layer and thus the impact ionization in the channel become smaller. In addition, the replaced InGaAs/InP composite channel with the same thickness in the same asymmetrically recessed structure increases the breakdown voltage to 5 V due to the smaller impact ionization and mobility of the InP layer at high drain voltage.

• Electrical & Electronic Materials
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• v.11 no.8
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• pp.19-24
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• 1998

• Proceedings of the Korean Vacuum Society Conference
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• 1995.02a
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• pp.39-40
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• 1995

• Proceedings of the Korean Vacuum Society Conference
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• 1996.06a
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• pp.46-47
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• 1996