In this study, we investigate the effects of electron temperature T
e on the production of nanoparticles by using the grid-biasing method in hollow-typed magnetron radio frequency (RF) CH4/H2 plasma. We find that nanoparticles are produced in low-T
e plasma. On the other hand, thin film depositions, such as nanowalls, are mainly observed and almost no nanoparticles are created in high-T
e plasma. This implies that a reduction in the CH2/CH3 radical ratio is important for producing nanoparticles, together with a reduction in sheath potential in front of the substrate. The change in electron temperature in plasma has a marked effect on film quality.