Methyl-terminated Si(111) surface was successfully fabricated using a photochemical grafting technique. This methylated surface was formed by illuminating visible light onto a hydrogen-terminated Si(111) surface that was immersed in a Grignard-tetrahydrofuran solution. It had an oxide-inhibiting property and atomically flat surface. In addition, the water contact angle improved with grafting parameters such as illumination time and light intensity and went as high as (89.0 +/- 0.80)degrees. This improvement was associated with the increase in the fraction of the silicon surface grafted with methyl groups.