Evaluation of deposition charactristics of hydrogenated amorphous carbon films using cumene plasma chemical vapor deposition

Hydrogenated amorphous carbon (a-C:H) films are crucial for semiconductor hard masks due to their durability. This study explores high-density, low-stress a-C:H film deposition using plasma chemical vapor deposition (CVD) with cumene (C9H12) as an unconventional precursor, compared to methane (CH4) and acetylene (C2H2). Deposition characteristics were evaluated based on precursor concentration, reactor pressure, and self-bias voltage, with Raman spectroscopy used for structural analysis. Films deposited using cumene exhibited superior properties, with mass density varying from 1.0 to 2.0 g/cm³ depending on self-bias voltage. At lower voltages (60–230 V), the films were polymer-like with high hydrogen content, while at higher voltages (580–1100 V), they were hard with lower hydrogen content. Methane and acetylene films showed a narrower density range (1.4–2.0 g/cm³). These results suggest that film structure can be effectively tuned via self-bias voltage, primarily influenced by molecular carbon content rather than precursor species, highlighting cumene’s potential for advanced applications.