Lateral effect of oxidation enhanced diffusion in silicon

The lateral enhancement of diffusion of the dopants in the unoxidized regions of silicon adjacent to the oxidation mask is studied. Experimental results agree well with the theoretical calculation which is an analytical soultion for two-dimensional diffusion equation for interstitial silicon atoms. Both experimental results and the theoretical calculation show that the extent of the lateral enhancement depends on the depth under the oxidation mask and that this enhancement extends longer lateral distance at the deeper junction. Because the range of the lateral enhacement is larger than VLSI device dimensions, this enhancement has significant effects on device characteristics.