Short-chain aminosilanes, namely, bis(N,Ndimethylamino)dimethylsilane (DMADMS) and (N,Ndimethylamino)trimethylsilane (DMATMS), have been used as Si precursors for atomic layer deposition (ALD) of SiO 2 . In this work, the DMADMS and DMATMS Si precursors are utilized as inhibitors for area-selective ALD (AS-ALD). The inhibitors selectively adsorb on a SiO 2 surface but not on H− Si, so that SiO 2 becomes selectively deactivated toward subsequent ALD. The deactivation of the SiO 2 surface by the inhibitors was investigated using various experimental and theoretical methods, including surface potential measurements, spectroscopic ellipsometry, and X-ray photoelectron spectroscopy. Better inhibition was observed for ALD of Ru and Pt than for ALD of Al 2 O 3 and HfO 2 . Through quantum mechanical and stochastic simulations, the difference in the blocking ability for noble metal and metal oxide ALD by the aminosilane inhibitors could be attributed to the inherently partial surface coverage by the inhibitors at their saturation and the reactivity of the subsequent ALD precursors. As silane inhibitors can be easily integrated with vacuum-based processes to facilitate high volume manufacturing of upcoming electronic devices, the current study provides a potential approach for the utilization of AS-ALD in pattern fabrication inside 3D nanostructures.
Indium–gallium–zinc oxide (IGZO) films, deposited by sputtering at room temperature, still require activation to achieve satisfactory semiconductor characteristics. Thermal treatment is typically carried out at temperatures above 300 °C. Here, we propose activating sputter- processed IGZO films using simultaneous ultraviolet and thermal (SUT) treatments to decrease the required temperature and enhance their electrical characteristics and stability. SUT treatment effectively decreased the amount of carbon residues and the number of defect sites related to oxygen vacancies and increased the number of metal oxide (M–O) bonds through the decomposition-rearrangement of M–O bonds and oxygen radicals. Activation of IGZO TFTs using the SUT treatment reduced the processing temperature to 150 °C and improved various electrical performance metrics including mobility, on-off ratio, and threshold voltage shift (positive bias stress for 10,000 s) from 3.23 to 15.81 cm2/Vs, 3.96 × 107 to 1.03 × 108, and 11.2 to 7.2 V, respectively.
We investigated the use of high-pressure gases as an activation energy source for
amorphous indium-gallium-zinc-oxide (a-IGZO) thin film transistors (TFTs).
High-pressure annealing (HPA) in nitrogen (N2) and oxygen (O2)
gases was applied to activate a-IGZO TFTs at 100 °C at
pressures in the range from 0.5 to 4 MPa. Activation of the a-IGZO TFTs
during HPA is attributed to the effect of the high-pressure environment, so that the
activation energy is supplied from the kinetic energy of the gas molecules. We
reduced the activation temperature from 300 °C to
100 °C via the use of HPA. The electrical characteristics of
a-IGZO TFTs annealed in O2 at 2 MPa were superior to those
annealed in N2 at 4 MPa, despite the lower pressure. For
O2 HPA under 2 MPa at 100 °C, the
field effect mobility and the threshold voltage shift under positive bias stress
were improved by 9.00 to 10.58 cm2/V.s and 3.89 to
2.64 V, respectively. This is attributed to not only the effects of the
pressurizing effect but also the metal-oxide construction effect which assists to
facilitate the formation of channel layer and reduces oxygen vacancies, served as
electron trap sites.
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