Plasma-enhanced chemical vapor deposited (PECVD) silicon oxide (SiOx) thin films have been widely used in Micro/Nano Electro Mechanical Systems to form electrical and mechanical components. In this paper, we explore the use of nanoindentation techniques as a method of measuring equivalent stress-strain curves of the PECVD SiOx thin films. Four indenter tips with different geometries were adopted in our experiments, enabling its to probe the elastic, elasto-plastic, and fully plastic deformation regimes of the PECVD SiOx thin films. The initial yielding point (sigma(1)) and stationary yielding point (sigma(11))(_) are separately identified for the as-deposited and annealed PECVD SiOx thin films, as well as a standard fused quartz sample. Based on the experimental results, a shear transformation zone based amorphous plasticity theory is applied to depict the plastic deformation mechanism in the PECVD SiOx. (C) 2007 Elsevier B.V. All rights reserved.