ABSTRACTLaser ablation of semiconductors presents an increasing interest for both thin film growth and surface modification. We present herein a study of the damage produced in bulk silicon by nanoseconds UV laser pulses with energy above the melting threshold. This study is carried out with a Raman microprobe. Polarized microRaman was used to reveal the main changes in the melted and recrystallized volume. These changes were observed in the liquid/solid boundaries, where tensile stress due to the induced thermal wave is more important. The morphology of the melted region evidences matter accumulation at such a boundary.
AbstractRecently, thin films of polytetrafluroethylene (PTFE) have been grown using pulsed laser ablation of TeflonTM at 266 nm.1,2 To provide further insight into the growth mechanisms we have examined the neutral and charged particle emissions generated in vacuum by 0 - 3 J/cm2 pulses of 248 nm radiation incident on solid PTFE. Measurements include quadrupole and time-of-flight mass spectroscopy. We find in addition to the neutral monomer (C2F4), copious emissions of highly reactive neutral and charged radicals, e.g., CF2, CF3, CF, F, and Cx. A careful analysis of the fluence dependence of these products provides definitive evidence that their precursors are generated by a thermally driven unzipping reaction. Models for the production of the radical species with the observed energies (several eV) involving gas phase processes are presented. Implications for improving PTFE thin film growth will be discussed.
We developed a thin film growth with a radical-initiated cross-linking of vinyl groups in a layer-by-layer manner via molecular layer deposition (MLD). The cross-linked film exhibited improved properties like 12% higher density and enhanced stability compared to the non-cross-linked film.
Atomic layer deposition (ALD) is a thin film growth technique that uses self-limiting, sequential reactions localized at the growing film surface. It guarantees exceptional conformality on high-aspect-ratio structures and controllability...
Alkyl chain assisted thin film growth of 2,7-dioctyloxy-benzothienobenzothiophene