Robust SiO2 gate dielectric thin films prepared through plasma-enhanced atomic layer deposition involving di-sopropylamino silane (DIPAS) and oxygen plasma: Application to amorphous oxide thin film transistors

초록

DIPAS (di-isopropylamino silane, H3Si[N(C3H7)(2)]) and O-2 plasma were employed, using plasma-enhanced atomic layer deposition (PEALD), to deposit silicon oxide to function as the gate dielectric at low temperature, i.e., below 200 degrees C. The superior amorphous SiO2 thin films were deposited through the self-limiting reactions of atomic layer deposition with a deposition rate of 0.135 nm/cycle between 125 and 200 degrees C. PEALD-based SiO2 thin layer films were applied to amorphous oxide thin film transistors constructed from amorphous In-Ga-Zn-O (IGZO) oxide layers, which functioned as channel layers in the bottom-gated thin film transistor (TFT) structure, with the aim of fabricating transparent electronics. The Si02 gate dielectric exhibited the highest TFT performance through the fabrication of heavily doped n-type Si substrates, with a saturation mobility of 16.42 cm(2)/Vs, threshold voltage of 2.95 V and large on/off current ratio of 3.69 x 10(8). Ultimately, the highly doped Si was combined with the ALD-based SiO2 gate dielectric layers, leading to a saturation mobility of 16.42 cm(2)/Vs, threshold voltage of 2.95 V, S-slope of 0.1944, and on/off current ratio of 3.69 x 10(8). Semi-transparent and transparent TFTs were fabricated and provided saturation mobilities of 22.18 and 24.29 cm(2)/Vs, threshold voltages of 4.18 and 2.17 V, S-slopes of 0.1944 and 0.1945, and on/off current ratios of 9.63 x 10(8) and 1.03 x 10(7), respectively.

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