• Title/Summary/Keyword: Design of Epitaxial layers

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Optimization Study on the Epitaxial Structure for 100nm-Gate MHEMTs with InAlAs/InGaAs/GaAs Heterostructure (InAlAs/InGaAs/GaAs 100 nm-게이트 MHEMT 소자의 에피 구조 최적화 설계에 관한 연구)

  • Son, Myung-Sik
    • Journal of the Semiconductor & Display Technology
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    • v.10 no.4
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    • pp.107-112
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    • 2011
  • This paper is for improving the RF frequency performance of a fabricated 100nm ${\Gamma}$-gate MHEMT, scaling down vertically for the epitaxy-structure layers of the device. Hydrodynamic simulation parameters are calibrated for the fabricated MHEMT with the modulation-doped $In_{0.52}Al_{0.48}As/In_{0.53}Ga_{0.47}$As heterostructure grown on the GaAs substrate. With these calibrated parameters, simulations for the vertically-scaled epitaxial layers of the device are performed and analyzed for DC/RF characteristics, including the quantization effect due to the thickness reduction of InGaAs channel layer. A newly designed epitaxy-structure device shows higher extrinsic transconductance, $g_m$ of 1.556 S/mm, and higher frequency performance, $f_T$ of 222.5 GHz and $f_{max}$ of 849.6 GHz.

Study on the Breakdown Simulation for InAlAs/InGaAs/GaAs MHEMTs with an InP-etchstop Layer (InP 식각정지층을 갖는 InAlAs/InGaAs/GaAs MHEMT 소자의 항복 특성 시뮬레이션에 관한 연구)

  • Son, Myung Sik
    • Journal of the Semiconductor & Display Technology
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    • v.11 no.2
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    • pp.53-57
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    • 2012
  • This paper is for accurately simulating the breakdown of MHEMTs with an InP-etchstop layer. 2D-Hydrodynamic simulation parameters are investigated and calibrated for the InP-epitaxy layer. With these calibrated parameters, simulations are performed and analyzed for the breakdown of devices with an InP-etchstop layer. In the paper, the impact-ionization coefficients, the mobility degradation due to doping concentration, and the saturation velocity for InP-epitaxy layer are newly calibrated for more accurate breakdown simulation.

Simulation Study on the Breakdown Enhancement for InAlAs/InGaAs/GaAs MHEMTs with an InP-Etchstop Layer (InP 식각정지층을 갖는 InAlAs/InGaAs/GaAs MHEMT 소자의 항복 전압 개선에 관한 연구)

  • Son, Myung Sik
    • Journal of the Semiconductor & Display Technology
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    • v.12 no.3
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    • pp.23-27
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    • 2013
  • This paper is for enhancing the breakdown voltage of MHEMTs with an InP-etchstop layer. Gate-recess structures has been simulated and analyzed for the breakdown of the devices with the InP-etchstop layer. The fully removed recess structure in the drain side of MHEMT shows that the breakdown voltage enhances from 2V to almost 4V and that the saturation current at gate voltage of 0V is reduced from 90mA to 60mA at drain voltage of 2V. This is because the electron-captured negatively fixed charges at the drain-side interface between the InAlAs barrier layer and the $Si_3N_4$ passivation layer deplete the InGaAs channel layer more and thus decreases the electron current passing the channel layer. In the paper, the fully-recessed asymmetric gate-recess structure at the drain side shows the on-breakdown voltage enhancement from 2V to 4V in the MHEMTs.

Simulation Study on the Breakdown Characteristics of InGaAs/InP Composite Channel MHEMTs with an InP-Etchstop Layer (InP 식각정지층을 갖는 MHEMT 소자의 InGaAs/InP 복합 채널 항복 특성 시뮬레이션)

  • Son, Myung Sik
    • Journal of the Semiconductor & Display Technology
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    • v.12 no.4
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    • pp.21-25
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    • 2013
  • This paper is for enhancing the breakdown voltage of MHEMTs with an InP-etchstop layer. The fully removed recess structure in the drain side of MHEMT shows that the breakdown voltage enhances from 2 V to 4 V in the previous work. This is because the surface effect at the drain side decreases the channel current and the impact ionization in the channel at high drain voltage. In order to increase the breakdown voltage at the same asymmetric gate-recess structure, the InGaAs channel structure is replaced with the InGaAs/InP composite channel in the simulation. The simulation results with InGaAs/InP channel show that the breakdown voltage increases to 6V in the MHEMT as the current decreases. In this paper, the simulation results for the InGaAs/InP channel are shown and analyzed for the InGaAs/InP composite channel in the MHEMT.