TY - JOUR
T1 - Density functional theory study on the modification of silicon nitride surface by fluorine-containing molecules
AU - Chowdhury, Tanzia
AU - Hidayat, Romel
AU - Kim, Hye Lee
AU - Mayangsari, Tirta Rona
AU - Cho, Seongjae
AU - Park, Sangjoon
AU - Jung, Jongwan
AU - Lee, Won Jun
N1 - Publisher Copyright:
© 2021 Elsevier B.V.
PY - 2021/7/15
Y1 - 2021/7/15
N2 - Gaseous fluorine-containing molecules are crucial for controlled etching in semiconductor industries. This work presents the first-principle density functional theory (DFT) study on the modification of silicon nitride surface by fluorine-containing gases such as HF, CF4, CHF3, CH2F2, and CH3F. The reactions were modeled and simulated by assuming that the silicon nitride surface was exposed to a single fluorine-containing molecule to form different resulting surface groups and byproducts. For all fluorine-containing molecules, the SiF* formation was expected to be spontaneous. For the CHxF4−x (x = 0 to 3) molecules, the formation of SiNHCHxF3−x* was also predicted as an exothermic reaction. In the case of CH3F only, the activation energy (EA) for the SiF* formation was 0.98 eV, which is significantly lower than 2.03 eV for the SiNHCH3* formation. For the other CHxF4−x molecules, the activation energies for the formation of SiNHCHxF3−x* and SiF* were approximately the same. For the SiF* formation, CH3F showed the lowest EA value on the silicon nitride surface, whereas HF showed the lowest EA value on the silicon oxide surface. The selective fluorination of silicon nitride with CH3F was explained using the absence of fluorine in the CH3 after the dissociation of a fluorine atom and the basicity of the silicon nitride surface. These findings imply that with a good selection of a fluorine-containing gas, SiF* can be selectively produced on a specific surface.
AB - Gaseous fluorine-containing molecules are crucial for controlled etching in semiconductor industries. This work presents the first-principle density functional theory (DFT) study on the modification of silicon nitride surface by fluorine-containing gases such as HF, CF4, CHF3, CH2F2, and CH3F. The reactions were modeled and simulated by assuming that the silicon nitride surface was exposed to a single fluorine-containing molecule to form different resulting surface groups and byproducts. For all fluorine-containing molecules, the SiF* formation was expected to be spontaneous. For the CHxF4−x (x = 0 to 3) molecules, the formation of SiNHCHxF3−x* was also predicted as an exothermic reaction. In the case of CH3F only, the activation energy (EA) for the SiF* formation was 0.98 eV, which is significantly lower than 2.03 eV for the SiNHCH3* formation. For the other CHxF4−x molecules, the activation energies for the formation of SiNHCHxF3−x* and SiF* were approximately the same. For the SiF* formation, CH3F showed the lowest EA value on the silicon nitride surface, whereas HF showed the lowest EA value on the silicon oxide surface. The selective fluorination of silicon nitride with CH3F was explained using the absence of fluorine in the CH3 after the dissociation of a fluorine atom and the basicity of the silicon nitride surface. These findings imply that with a good selection of a fluorine-containing gas, SiF* can be selectively produced on a specific surface.
KW - Density functional theory (DFT)
KW - Fluorination reaction
KW - Selectivity
KW - Silicon
KW - Silicon nitride
KW - Silicon oxide
UR - http://www.scopus.com/inward/record.url?scp=85103269733&partnerID=8YFLogxK
U2 - 10.1016/j.apsusc.2021.149481
DO - 10.1016/j.apsusc.2021.149481
M3 - Article
AN - SCOPUS:85103269733
SN - 0169-4332
VL - 554
JO - Applied Surface Science
JF - Applied Surface Science
M1 - 149481
ER -