Physics-based analytical channel charge model of InxGa1-xAs/In0.52Al0.48As quantum-well field-effect transistors from subthreshold to strong inversion regimes

• Published in: IEEE journal of the Electron Devices Society 2022, Vol.10, p.1-1
• Main Authors: Jeong, Hyeon-Seok, Park, Wan-Soo, Jo, Hyeon-Bhin, Lee, In-Geun, Kim, Tae-Woo, Tsutsumi, Takuya, Sugiyama, Hiroki, Matsuzaki, Hideaki, Hahm, Sung-Ho, Lee, Jae-Hak, Kim, Dae-Hyun
• Format: Article
• Language: English
• Subjects: Analytical models; HEMTs; III-V semiconductor materials; In<italic xmlns:ali="http://www.niso.org/schemas/ali/1.0/" xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance">x Ga1-<italic xmlns:ali="http://www.niso.org/schemas/ali/1.0/" xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance">x As/In0.52Al0.48As QW FETs; Integrated circuit modeling; Inversion regime; InxGa1-xAs/In0.52Al0.48As QW FETs; Logic gates; MODFETs; Near-threshold regime; Semiconductor device modeling; Subthreshold regime; two-dimensional electron-gate density (<italic xmlns:ali="http://www.niso.org/schemas/ali/1.0/" xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance">n ₂-<italic xmlns:ali="http://www.niso.org/schemas/ali/1.0/" xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance">DEG ); Two-dimensional electron-gate density (n2-DEG)
• ISSN: 2168-6734
• DOI: 10.1109/JEDS.2022.3171437

This paper presents a physics-based analytical channel charge model for indium-rich InxGa1-xAs/In0.52Al0.48As quantum-well (QW) field-effect transistors (FETs) that is applicable from the subthreshold to strong inversion regimes. The model requires only seven physical/geometrical parameters, along with three transition coefficients. In the subthreshold regime, the conduction bands (EC) of all regions are flat with finite and symmetrical QW configurations. Since the Fermi-level (EF) is located far below EC, the two-dimensional electron-gas density (n2-DEG) should be minimal and can thus be approximated from Maxwell-Boltzmann statistics. In contrast, the applied gate bias lowers the EC of all structures in the inversion regime, yielding band-bending of an In0.52Al0.48As insulator and InxGa1-xAs QW channel. The dependency of the energy separation between EF and EC on the surface of the InxGa1-xAs QW channel upon VGS enables construction of the charge-voltage behaviors of InxGa1-xAs/In0.52Al0.48As QW FETs. To develop a unified, continuous and differentiable areal channel charge density (Qch) model that is valid from the subthreshold to strong inversion regimes, the previously proposed inversion-layer transition function is further revised with three transition coefficients of η,α and β in this work. To verify the proposed approach, the results of the proposed model are compared with those of not only the numerically calculated Qch from a one-dimensional (1D) Poisson-Schrodinger solver, but also the measured gate capacitance of a fabricated In0.7Ga0.3As QW metal-insulator-semiconductor FET with large gate length, yielding excellent agreement between the simulated and measured results.