Atmosphere-Regulated Conversion of Perhydropolysilazane (PHPS): Controlling Si-O-N Composition and Unveiling...

Area of Science:

• Materials Science
• Chemical Engineering
• Computational Chemistry

Background:

• Perhydropolysilazane (PHPS) is a key precursor for silica-based materials used in semiconductors.
• Its complex structure and sensitivity to atmosphere hinder understanding of its conversion mechanism to SiO_x/SiO_xN_y.

Purpose of the Study:

• To elucidate the atomistic mechanisms governing PHPS thermal conversion under different atmospheric conditions.
• To develop a reliable computational model for simulating PHPS conversion.

Main Methods:

• Development of a new Si/N/O/H ReaxFF parameter set.
• ReaxFF molecular dynamics (MD) simulations under various O₂/H₂O atmospheres.
• Coordination analysis of resulting structures.

Main Results:

• Distinct pathways for O₂ and H₂O: O₂ promotes SiO_x formation and surface passivation, while H₂O facilitates NH₃ release and Si-N bond cleavage.
• Si-N tetrahedra are sensitive to atmosphere; higher O₂ favors Si atoms bonded to four N atoms.
• The Si-O-N composition of PHPS-derived materials can be tuned by controlling the conversion atmosphere.

Conclusions:

• The study provides atomistic insights into PHPS conversion mechanisms.
• Findings offer practical guidance for optimizing processing and enhancing material performance.
• This work facilitates the rational design of high-performance inorganic functional materials from PHPS.