Low-temperature, high-growth-rate ALD of SiO_2 using aminodisilane precursor

摘要

In the present study, SiO2 was deposited using the atomic layer deposition (ALD) with a 1,2-bis(diisopropylamino)disilane (BDIPADS) precursor. The use of this precursor exhibited a higher growth rate and lower initial growth temperature than the use of diisopropylaminosilane (DIPAS) did. The ALD reaction using BDIPADS produced SiO2 with excellent quality owing to the self-catalytic reaction between the amine ligand and O-3; therefore, the SiO2 film has no impurities. When the growth temperature was increased gradually, the stoichiometry and density of SiO2 were improved also because the reaction between surface adsorbate species was nearly complete. ALD SiO2 exhibited a higher dielectric constant than the bulk SiO2 did, from the metal-oxide-semiconductor capacitor, because of the incorporated hydroxyl groups in the film. Furthermore, the etching characteristics were modulated by changing the growth temperature to ensure that the film can be used as a hard mask for lithography. From the DFT calculation, high reaction energy between the BDIPADS and Si-OH was observed. Moreover, the Si-Si cleavage results in the existence additional reaction sites, such as amine group, allowing low-temperature growth and enhanced productivity. Therefore, the number of Si atoms in a molecule affects the growth rate and initial growth temperature to ensure that BDIPADS is a highly excellent precursor for the SiO2 deposition; therefore, its use can lead to a remarkably high productivity.