Patent ID: 6232165
Filing Date: 2001-05-15
Classification: H01L

Abstract:
A method for forming a semiconductor device having a buried guard ring, comprising:forming a plurality of shallow trenches in a substrate;providing a first photoresist over said substrate;patterning and defining said photoresist;implanting said substrate with a dopant to form said buried guard ring for sinking charged carriers, said buried guard ring extending underneath at least one of said plurality of shallow trenches;removing said photoresist;oxidizing said substrate to grow oxides inside said plurality of shallow trenches to form a plurality of shallow trench isolations;forming an MOS device over said substrate, including the steps ofimplanting a first dose of dopants to form spaced-apart regions, andforming a gate structure including a gate electrode and a gate insulator having spacer oxides, andimplanting a second dose of dopants into said buried guard ring and said spaced-apart regions, said second dose of dopants being more concentrated than said first dose of dopants.