Room-Temperature Atomic Layer Deposition of Aluminum Silicate for Molecule Sorption

Abstract

A room-temperature atomic layer deposition (RT-ALD) of aluminum silicate for molecule sorption is developed using trimethylaluminum (TMA) and trismethylaminosilane (TDMAS) using a plasma excited humidified argon. The aluminum-silicate is a main material of zeolites that is used for cation sorption. If we achieved the aluminum silicate deposition on flexible films, we could expect the film used as a regenerable ion exchange filter. The schematic of ALD system is shown in Fig.1. TMA and TDMAS were introduced with mass flow controllers. A remote plasma system generating excited humidified argon was installed to the ALD chamber. The source gas for the oxidizing gas is a mixture of water vapor and argon. The plasma was generated in a glass tube with an induction coil with a frequency of 13.56 MHz and a RF power of 100 W. For the deposition, we repeated the cycle of TDMAS and TMA saturation and oxidizing gas treatment at RT. To control the aluminum to Si atomic ratio in the aluminum silicate, we adjusted the initial exposure of TDMAS. To confirm the Na sorption ability of the aluminum silicate film deposited by the present technology, we immersed the aluminum silicate coated Si sample in a 100 mM NaCl solution for 3h. The dried sample was evaluated by X-ray photoelectron spectroscopy. As shown in Fig. 2, the enhanced Na adsorption is confirmed. In the conference, we discuss the mechanism of Na sorption on the RT deposited aluminum silicate. Acknowledgements This work was partly supported by JSPS KAKENHI Grant Numbers 15H03536. It was also partly supported by JST-CREST Grant Number JPMJCR14F3, Japan. Figure 1