Peculiarities of Formation and Growth of Thin Polymer Plasma-Deposited Films

Special features of the formation and growth of polymer films, formed on steel under the effect of glow discharge in heptane were studied by means of atomic force microscopy, X-ray photoelectron spectroscopy and contact wetting angle. At low film thickness a thin sticky layer is formed, from which macromolecular cone-shaped formations protrude. With an increase in film thickness the sticky layer disappears and the number of cone-shaped formations increase and they eventually coalesce. As the surface coverage with cones increases the films become thicker and stronger. The cones are assumed to be the film growth sites, which arise during the relaxation of the film’s internal stresses. In addition these growth sites can form under the effect of the stresses from extended defects in the substrate.

Si(100) Nitridation by Remote Plasmas for Enhanced High-κ Gate Performance

ABSTRACTHafnium oxide is the leading high-κ candidate for next generation CMOS devices, however, it is plagued by problems such as a propensity to react with the Si(100) substrate, to crystallize, and to have fixed and trapped charges and low transistor mobilities. A remote N2/He plasma was used as a reactant during MOCVD with Hf (IV) t-butoxide which incorporates 6 at.% nitrogen located at the film-substrate interface and reduces the interdiffusion problem upon anneal [1]. A new process for pretreating the silicon wafer with a N2/He plasma was developed to improve nitrogen concentrations at the interface and reduce interdiffusion further. Films deposited with N2/He plasma and the pretreatment method were compared to O2/He plasma deposited films and N2/He plasma deposited films without the nitridation step. It is shown that a 16Å interface SiNx layer is sufficient to prevent reaction during a 1000°C Ar/O2 anneal at atmosphere and an intermediate annealing step is crucial for desired reduction in interdiffion. Thick films show some crystalline peaks by XRD which are suppressed using the N2 process. Electrical measurements on thick films show the pretreatment process results in the lowest leakage current density and the highest dielectric constant of 21.5.