The influence of substrate temperature during plasma-assisted atomic layer deposition (PAALD) of porous low-k SiOC(-H) thin films on p-type Si(100) substrates is reported. Dimethoxydimethylsilane and porogen were used as precursors, and the deposited films were then annealed at 425 °C for 1 hour in ambient N2 to remove the porogen. The optical, chemical, and electrical characteristics of the porous low-k SiOC(-H) film were investigated using ellipsometry, Fourier-transform infrared spectroscopy, and capacitance-voltage measurements, respectively. The refractive indices and the dielectric constants of porous low-k SiOC(-H) films showed remarkable decreases and increases with increasing substrate temperature up to 100 °C and greater than 150 °C, respectively. We also show that for substrate temperatures the open pores can be sealed by using a layer-by-layer deposition method. Furthermore, using PAALD, we developed a novel technique to deposit high-quality, porous low-k SiOC(-H) films and to seal open pores at relatively low substrate temperatures. © 2013 The Korean Physical Society.