Polycrystalline silicon thin-film transistor utilizing self-assembled monolayer for crystallization

• We proposed self-assembled monolayer coating process with Ni-complex solution.
• Our process produced poly-Si thin-films with the gain size of 47 μm.
• A field effect mobility of the thin-film transistor reached around 100 cm2/Vs.
• Realization of low Ni contamination in the poly-Si yielded quite low off-current.

Crystallization employing an N-(2-aminoethyl)-3-aminopropyltrimethoxysilane self-assembled monolayer (AEAPS-SAM) to coordinate Ni metal catalyst was found to produce large grain poly-Si. A small concentration of Ni could be deposited controllably onto an AEAPS-SAM covered with Si by immersing it in Ni solution for 1–60 min. Larger grains and a lower Ni concentration in the poly-Si could be obtained by shorter immersion. Immersion for 1 min produced grains, as large as 47 μm and a Ni concentration as low as 7.4 × 1018 atoms/cm3. A poly-Si thin-film transistor fabricated with AEAPS-SAM poly-Si of 1 min immersion had a field-effect mobility of 98 cm2/(V s), which is one order of magnitude higher than that of a thin-film transistor fabricated without the AEAPS-SAM treatment.