We present our recent findings on the strong gettering effect of dielectric films for removing impurities from the silicon bulk. Iron was used as a model impurity in silicon to study the gettering effects. The iron concentration in silicon is found to be significantly reduced after annealing silicon wafers coated with either plasma-enhanced chemical vapour deposited (PECVD) silicon nitride (SiN x) films, or atomic layer deposited (ALD) aluminium oxide (Al 2 O 3) films. Both PECVD SiN x coated and ALD Al 2 O 3 coated silicon wafers demonstrate largely diffusion-limited iron reduction rates at around 400 o C, removing half of the bulk iron concentration within 30 min for a 160-µm thick silicon wafer with dielectric films on both sides. PECVD SiN x films are shown to achieve diffusion-limited gettering of iron at temperatures below 700 o C, meaning that 90% of iron can be gettered by the surface SiN x films within 5 min for a 260-µm silicon wafer, or within 2 min for a 160-µm wafer at 700ºC. Secondary ion mass spectrometry reveals that the gettering effect of PECVD SiN x films is caused by impurity segregation into the bulk of the SiN x films, and the gettering effect of ALD Al 2 O 3 films comes from impurity accumulation at the Al 2 O 3 /Si interfaces.