Formation of isolation layer over trench capacitor

摘要

A method for controlling isolation layer thickness in trenches for semiconductor devices includes the steps of providing a trench (14) having a conductive material (24) formed therein, forming a liner (36) on sidewalls of the trench above the conductive material, depositing a selective oxide deposition layer (40) on the conductive material and the sidewalls, the selective oxide deposition layer selectively growing at an increased rate on the conductive material (24) than on the liner (36) of the sidewalls and a top surface (43) and removing the selective oxide deposition layer except for a portion in contact (42) with the conductive material (24) to form an isolation layer on the conductive material in the trench. The present invention advantageously employs a sub-atmospheric chemical vapor deposition (SACVD) process to deposit an oxide within the deep trench where the sidewalls have been lined with a nitride layer. The SACVD oxide is an ozone activated TEOS process which grows selectively at a deposition rate of about 5 times greater on silicon than on nitride.