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This paper investigates the feasibility of using a lanthanum oxide thin film (La2O3) with a high dielec-tric constant as a gate dielectric on GaAs pHEMTs to reduce gate leakage current and improve the gate to drain breakdown voltage relative to the conventional GaAs pHEMT.An E/D mode pHEMT in a single chip was real-ized by selecting the appropriate La2O3 thickness.The thin La2O3 film was characterized:its chemical composition and crystalline structure were determined by X-ray photoelectron spectroscopy and X-ray diffraction,respectively.La2O3 exhibited good thermal stability after post-deposition annealing at 200,400 and 600°C because of its high binding-energy (835.6 eV).Experimental results clearly demonstrated that the La2O3 thin film was thermally stable.The DC and RF characteristics of Pt/La2O3/Ti/Au gate and conventional Pt/Ti/Au gate pHEMTs were examined.The measurements indicated that the transistor with the Pt/La2O3/Ti/Au gate had a higher breakdown voltage and lower gate leakage current.Accordingly,the La2O3 thin film is a potential high-k material for use as a gate dielectric to improve electrical performance and the thermal effect in high-power applications.
This paper investigates the feasibility of using a lanthanum oxide thin film (La2O3) with a high dielec-tric constant as a gate dielectric on GaAs pHEMTs to reduce gate leakage current and improve the gate to drain breakdown voltage relative to the conventional GaAs pHEMT. An E / D mode pHEMT in a single chip was real-ized by selecting the appropriate La2O3 thickness.The thin La2O3 film was characterized: its chemical composition and crystalline structure were determined by X-ray photoelectron spectroscopy and X-ray diffraction, respectively. La2O3 exhibited good thermal stability after post-deposition annealing at 200,400 and 600 ° C because of its high binding-energy (835.6 eV). Experimental results show that the La2O3 thin film was thermally stable. The DC and RF characteristics of Pt / La2O3 / Ti / Au gate and conventional Pt / Ti / Au gate pHEMTs were examined. The measurements indicated that the transistor with the Pt / La2O3 / Ti / Au gate had a higher breakdown voltage and lower gate lea kage current.Accordingly, the La2O3 thin film is a potential high-k material for use as a gate dielectric to improve electrical performance and the thermal effect in high-power applications.