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The effects of dielectric thin films on the performance of Ga N-based high-electron-mobility transistors(HEMTs) were reviewed in this work. Firstly, the nonpolar dielectric thin films which act as both the surface passivation layers and the gate insulators of the high-frequency Ga N-based high-electron-mobility transistors were presented. Furthermore, the influences of dielectric thin films on the electrical properties of two-dimensional electron gas(2DEG) in the Al Ga N/Ga N hetero-structures were analyzed. It was found that the additional in-plane biaxial tensile stress was another important factor besides the change in surface potential profile for the device performance improvement of the Al Ga N/Ga N HEMTs with dielectric thin films as both passivation layers and gate dielectrics. Then, two kinds of polar gate dielectric thin films, the ferroelectric LiNbO_3 and the fluorinated Al_2O_3,were compared for the enhancement-mode Ga N-based HEMTs, and an innovative process was proposed. At last,high-permittivity dielectric thin films were adopted as passivation layers to modulate the electric field and accordingly increase the breakdown voltage of Ga N-based HEMTs. Moreover, the polyimide embedded with Cr particles effectively increased the breakdown voltage of Ga Nbased HEMTs. Finally, the effects of high-permittivity dielectric thin films on the potential distribution in the driftregion were simulated, which showed an expanded electric field peak at the drain-side edge of gate electrode.
The effects of dielectric thin films on the performance of Ga N-based high-electron-mobility transistors (HEMTs) were reviewed in this work. High-frequency Ga N-based high-electron-mobility transistors were presented. The influences of dielectric thin films on the electrical properties of two-dimensional electron gas (2DEG) in the Al Ga N / Ga N hetero-structures were analyzed. It was found that the additional in-plane biaxial tensile stress was another important factor besides the change in surface potential profile for the device performance improvement of the Al Ga N / Ga N HEMTs with dielectric thin films as both passivation layers and gate dielectrics. Then, two kinds of polar gate dielectric thin films, the ferroelectric LiNbO 3 and the fluorinated Al 2 O 3, were compared for the enhancement-mode Ga N-based HEMTs, and an innovative process was proposed. At last, high-permittivity dielectric thin films were adopted as passivation layers to modulate the electric field and accordingly increase the breakdown voltage of Ga N-based HEMTs. Furthermore, the polyimide embedded with Cr particles efficiently increased the breakdown voltage of Ga Nbased HEMTs. Finally, the effects of high-permittivity dielectric thin films on the potential distribution in the drift region were simulated, which showed an expanded electric field peak at the drain-side edge of gate electrode.