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Silicon dioxide has been used as a primary gate dielectric material

Silicon dioxide has been used as a primary gate dielectric material in metal-oxide-semiconductor field effect transistors (MOSFETs) for over 30 years. However, as the dimension of MOSFET devices is scaled down to sub-0.1μm, higher dielectric constant materials are needed to allow the use of physically thicker gate dielectric with electrically equivalent oxide thickness (EOT). Also, amorphous structure material with highly stable interface on silicon is required. Among many high-k materials, hafnium silicate material is considered to be the most promising due to its thermodynamic stability in direct contact with silicon up to high temperatures. As a deposition process, Atomic layer deposition (ALD) is favoured to control the deposition process in an angstrom range. Since ALD is based on self-limiting reactions on the substrate surface, the growth rate depends only on the number of deposition cycles. Until now, several methods have been reported for ALD of hafnium silicate thin films. However, all these methods require the combination of a hafnium precursor with another silicon precursor, and a single precursor for hafnium silicate has been tried recently. Our previous work reported that a new ALD precursor HfCl2[N(SiMe3)2]2, which contains Si in ligands, can deposit hafnium silicate films using H2O as an oxidant. Still, the Si content in the film was relatively low. In the present work, two approaches were performed to increase Si content and improve the film properties. One uses hydrogen peroxide as a more potent oxidant than water, and the other uses tetra-n-butyl orthosilicate (TBOS, Si(OnBu)4) as an additional Si source. If you are looking for high quality, high purity and cost-effective silicon dioxide, or if you require the latest silicon dioxide price, please email contact mis-asia.

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