Method for annealing ultra-thin, high quality gate oxide layers using oxidizer/hydrogen mixtures

摘要

An embodiment of the present invention is a method of forming an ultra-thin dielectric layer, the method comprising the steps of: providing a substrate having a semiconductor surface; forming an oxygen-containing layer on the semiconductor surface; exposing the oxygen-containing layer to a nitrogen-containing plasma to create a uniform nitrogen distribution throughout the oxygen-containing layer; and re-oxidizing and annealing the layer to stabilize the nitrogen distribution, heal plasma-induced damage, and reduce interfacial defect density. This annealing step is selected from a group of four re-oxidizing techniques: Consecutive annealing in a mixture of H2 and N2 (preferably less than 20% H2), and then a mixture of O2 and N2 (preferably less than 20% O2); annealing by a spike-like temperature rise (preferably less than 1 s at 1000 to 1150° C.) in nitrogen-comprising atmosphere (preferably N2/O2 or N2O/H2); annealing by rapid thermal heating in ammonia of reduced pressure (preferably at 600 to 1000° C. for 5 to 60 s); annealing in an oxidizer/hydrogen mixture (preferably N2O with 1% H2) for 5 to 60 s at 800 to 1050° C.