An analytical model of diffusion current in intrinsically gettered structures based on intentional contamination experiments

The authors used the results of intentional iron implants into bulk wafers with intrinsic gettering (IG) to develop an analytical model suitable for calculating the diffusion current in both bulk and epitaxial wafer structures. The model is used to compare the improvement in diffusion current an epitaxial wafer provides over a bulk wafer. For typical structures factor reductions in diffusion current of 10 to 100× are predicted when using epitaxial wafers. Iron incorporated into a MOSFET device during its fabrication was seen to be effectively removed from the device by the presence of an adjacent region of IG. More important is the observation that the gettered impurities reside close to the device in the IG region and still act to increase the diffusion current into the junction