Ge-Channel Thin-Film Transistor with Schottky Source/Drain Fabricated by Low-Temperature Processing

概要

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The fabrication of Ge-channel thin-film transistors (TFTs) with Schottky source/drain (S/D) contacts was investigated. First, the annealing characteristics of Ni/c-Ge stacked structures were examined. NiGe/$n$-Ge Schottky contacts ($\phi_{\text{Bn}}=0.51$ eV, $n=1$) with a low reverse leakage current [$(2--5)\times 10^{-2}$ A/cm2] were obtained at 200–300 °C. Second, the electrical characteristics of Al/SiO2/c-Ge metal–oxide–semiconductor (MOS) structures were investigated, in which SiO2 films were formed by plasma-enhanced chemical vapor deposition at 250 °C. The MOS structures were proven acceptable for device operation. On the basis of the obtained results, TFTs with NiGe Schottky S/D contacts were fabricated using poly-Ge/quartz substrates. The maximum processing temperature was 500 °C in the solid-phase crystallization of a-Ge films. The TFTs showed good $ p$-channel operation characteristics with a mobility of ${\sim}100$ cm2 V-1 s-1 without showing kink effects. This is a great advantage for the realization of high-performance TFTs for system-in-displays.
Published by the Japan Society of Applied Physics through the Institute of Pure and Applied Physicsの論文
2007-03-30