Patent ID: 6140156
Filing Date: 2000-10-31
Classification: H01L

Abstract:
A method for fabrication of a photodiode comprising the steps of:providing a substrate;forming sequentially a pad oxide layer and a silicon nitride layer;patterning sequentially a silicon nitride layer, the pad oxide layer and the substrate to form an opening in the substrate;forming a spacer on a sidewall of the opening;forming a trench in the substrate using the spacer and the silicon nitride layer as a mask, wherein a width of the opening is wider than a width of the trench;forming an oxide plug to fill the trench and the opening;forming respectively a P-well region and an N-well region on two sides of the trench; andforming respectively an N+ type region and a P+ type region on two sides of the opening; wherein the N+ type region is located on the P-well region and the P+ type region is located on the N-well region, and only the N+ type region and the P+ type region respectively comprises corners at the junction between the N+ type region and P-well region and between the P+ type region and the N-well region so that a junction leakage current is avoided.