Characterization of Low-k Dielectric SiCOH Films Deposited with Decamethylcyclopentasiloxane and Cyclohexane

Abstract

Ultra low-k dielectric SiCOH films were deposited with decamethylcyclopentasiloxane (DMCPSO, C10H30O5Si5) and cyclohexane (C6H12) precursors by plasma-enhanced chemical vapor deposition at the deposition temperature between 25 and 200 degrees C and their chemical composition and deposition kinetics were investigated in this work. Low dielectric constants of 1.9-2.4 were obtained due to intrinsic nanoscale pores originating from the relatively large ring structure of DMCPSO and to the relatively large fraction of carbon contents in cyclohexane. Three different deposition regions were identified in the temperature range. Deposition rates increased with temperature below 40 degrees C and decreased as temperature increased to 75 degrees C with apparent activation energies of 56 kJ/mol x K at < 40 degrees C, -26 kJ/mol x K at 40-100 degrees C, respectively. In the temperature region of 40-100 degrees C hydrocarbon deposition and decomposition process compete each other and decomposition becomes dominant, which results in apparent negative activation energy. Deposition rates remain relatively unaffected with further increases of temperature above 100 degrees C. FTIR analysis and deposition kinetic analysis showed that hydrocarbon deposition is the major factor determining chemical composition and deposition rate. The hydrocarbon deposition dominates especially at lower temperatures below 40 degrees C and Si-O fraction increases above 40 degrees C. We believe that dielectric constants of low-k films can be controlled by manipulating the fraction of deposited hydrocarbon through temperature control.

Density functional theory study on the full ALD process of silicon nitride thin film deposition via BDEAS or BTBAS and NH3

“…A chemically active precursor allows the deposition to be carried out at a relatively low temperature. Recently, [14][15][16][17][18][19][20][21][22][23][24][25] aminosilanes providing breadth of structural variations have been proposed as Si precursors for the ALD process of SiO 2 thin film deposition, which would be more desirable than chlorosilanes from safety and operability perspectives. Among those Si precursors, bis(diethylamino)silane (BDEAS) and bis(tertiarybutylamino)silane (BTBAS) have been used as suitable Si precursors for the deposition of SiO 2 thin films through the ALD technique, as they can be deposited in a wide temperature range of 100-400 1C with a high deposition rate, as well as having good thermal stability.…”

Atomic layer deposition of silicon oxide films using bis(dimethylaminomethylsilyl)trimethylsilylamine and ozone: first-principles and experimental study

“…ALD using DTDN-2H2 shows a growth rate of 1.34 Å per cycle at 400 1C, which is significantly higher than 0.55 Å per cycle at the same temperature using tris-DMAS with one Si atom. 17 Higher growth rates of B2 Å per cycle were reported using tetrakis(ethylamino)silane (TEAS), 14 because the molecule consists of a monoalkylamido ligand with less steric hindrance than the dialkylamido ligand. This is the same reason why the chloride precursors showed high growth rates.…”

“…A variety of aminosilane compounds with different dialkylamido ligands have also been extensively studied as chlorinefree silicon precursors. They showed low-temperature deposition reactions with a small amount of precursor as compared with silicon chlorides, 13,14 which is mainly due to the high reactivity of the alkylamido ligand toward surface hydroxyl groups. 15 Therefore, ALD processes using diisopropylaminosilane (DIPAS, SiH 3 (N i Pr 2 )), bis(diethylamino)silane (BDEAS, SiH 2 (NEt 2 ) 2 ), or tris(dimethylamino)silane (tris-DMAS, SiH(NMe 2 ) 3 ) were adopted in semiconductor manufacturing.…”